ATL: LARRY - Advisories

[cycloneye]

BULLETIN
Tropical Depression Twelve Advisory Number 1
NWS National Hurricane Center Miami FL AL122021
800 PM CVT Tue Aug 31 2021

...NEW TROPICAL DEPRESSION FORMS IN THE EASTERN TROPICAL ATLANTIC...
...FORECAST TO INTENSIFY OVER THE NEXT COUPLE OF DAYS...


SUMMARY OF 800 PM CVT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...11.2N 21.1W
ABOUT 335 MI...535 KM SE OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 800 PM CVT (2100 UTC), the center of Tropical Depression Twelve
was located near latitude 11.2 North, longitude 21.1 West. The
depression is moving toward the west-northwest near 16 mph
(26 km/h). A turn toward the west is expected tonight, and a
westward motion at a faster forward speed is expected during the
next couple of days.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Strengthening is expected during the next couple of days and the
depression is expected to become a tropical storm tonight or on
Wednesday.

The estimated minimum central pressure is 1006 mb (29.71 inches).


HAZARDS AFFECTING LAND
----------------------
None.


NEXT ADVISORY
-------------
Next complete advisory at 200 AM CVT.

$$
Forecaster Beven

Tropical Depression Twelve Discussion Number 1
NWS National Hurricane Center Miami FL AL122021
800 PM CVT Tue Aug 31 2021

Satellite imagery, along with earlier scatterometer data, indicates
that the low pressure area over the eastern tropical Atlantic has
a well-defined circulation and sufficient organized convection to
be considered a tropical depression. Thus, advisories are being
initiated on Tropical Depression Twelve. The initial intensity is
set at 30 kt based on satellite intensity estimates from TAFB and
SAB as well as the scatterometer data.

The initial motion is a somewhat uncertain 285/14. A strong low-
to mid-level ridge to the north should cause the cyclone to move
westward at a faster forward speed for the next 36 h or so,
followed by a gradual turn toward the west-northwest and northwest
by the end of the period as the depression moves along the
southwest side of the ridge. There is some spread in the guidance
after 36-48 h, with the GFS and GFS ensemble mean showing a more
northward motion while the UKMET and the UKMET ensemble mean show a
more westward motion. The official forecast is near the middle of
the guidance envelope and is close to the HFIP corrected consensus
model, which is a little to the south of the other consensus models.

Conditions appear favorable for intensification during the next 72
h or so as the cyclone is in a moist environment with light shear
and warm sea surface temperatures. The intensity forecast thus
calls for the cyclone to become a tropical storm in 12 h or so and
reach hurricane strength in 48-60 h. By the end of the forecast
period, the forecast track takes the cyclone over slightly cooler
water and into a drier air mass. Based on this, the intensity
forecast calls for a slower development rate. The official
intensity forecast is in the middle of the intensity guidance, and
it is possibly conservative given that many of the global models
are showing the development of a large and powerful tropical
cyclone.

FORECAST POSITIONS AND MAX WINDS

INIT 31/2100Z 11.2N 21.1W 30 KT 35 MPH
12H 01/0600Z 11.6N 23.9W 35 KT 40 MPH
24H 01/1800Z 12.0N 27.5W 40 KT 45 MPH
36H 02/0600Z 12.1N 30.7W 50 KT 60 MPH
48H 02/1800Z 12.5N 33.7W 60 KT 70 MPH
60H 03/0600Z 13.3N 36.5W 70 KT 80 MPH
72H 03/1800Z 14.3N 39.0W 80 KT 90 MPH
96H 04/1800Z 16.5N 43.5W 85 KT 100 MPH
120H 05/1800Z 19.5N 47.5W 90 KT 105 MPH

$$
Forecaster Beven

[cycloneye]

Tropical Depression Twelve Discussion Number 2
NWS National Hurricane Center Miami FL AL122021
200 AM CVT Wed Sep 01 2021

Satellite images indicate that the depression is gradually becoming
better organized. An area of deep convection has been persisting
near the center, and banding features are beginning to take shape.
The latest Dvorak estimates from TAFB and SAB have increased to
2.5/35 kt, which would support upgrading the system to a tropical
storm. However, a recent ASCAT-B overpass around 2300 UTC showed
maximum winds in the 25-30 kt range in the northeastern quadrant,
and based on that data the initial intensity is held at 30 kt.

The tropical depression is moving fairly quickly to the
west-northwest at 17 kt. The track forecast reasoning appears
fairly straightforward. The cyclone is expected to move at a
relatively fast pace to the west or west-northwest during the next
couple of days as it remains on the south side of a strong mid-level
ridge. After that time, a decrease in forward speed and a gradual
turn to the northwest are expected as the system nears the
southwestern side of the ridge. Although most of the models agree
on the synoptic steering pattern, there is a fair amount of spread
from days 3 to 5 in how soon the northwestward turn will occur. The
NHC track forecast lies near the middle of the guidance envelope and
is a little to the north of the previous one based on the more
poleward initial position.

Since the system is expected to be over relatively warm water and in
an air mass of low wind shear and abundant moisture, steady
strengthening is expected during the next couple of days. The
depression is likely to become a tropical storm within the next 12
hours and a hurricane in 36 to 48 hours. Beyond a few days, an
increase in shear and drier air should slow the rate of
intensification. The NHC intensity forecast follows the trend of
the HCCA, IVCN, and IVDR models. In addition, the global models all
show the cyclone becoming fairly large toward the end of the
forecast period. The NHC forecast wind radii is larger than the
previous one, trending toward the radii consensus aid.


FORECAST POSITIONS AND MAX WINDS

INIT 01/0300Z 12.1N 23.2W 30 KT 35 MPH
12H 01/1200Z 12.6N 25.9W 40 KT 45 MPH
24H 02/0000Z 12.8N 29.2W 50 KT 60 MPH
36H 02/1200Z 13.2N 32.1W 60 KT 70 MPH
48H 03/0000Z 13.8N 35.1W 70 KT 80 MPH
60H 03/1200Z 14.5N 37.5W 80 KT 90 MPH
72H 04/0000Z 15.4N 40.1W 85 KT 100 MPH
96H 05/0000Z 18.0N 44.5W 90 KT 105 MPH
120H 06/0000Z 20.7N 47.9W 95 KT 110 MPH

$$
Forecaster Cangialosi

[cycloneye]

TCPAT2

BULLETIN
Tropical Storm Larry Advisory Number 3
NWS National Hurricane Center Miami FL AL122021
800 AM CVT Wed Sep 01 2021

...DEPRESSION STRENGTHENS INTO TROPICAL STORM LARRY OVER THE
EASTERN TROPICAL ATLANTIC...


SUMMARY OF 800 AM CVT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...12.3N 24.8W
ABOUT 175 MI...280 KM S OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 20 MPH...31 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 800 AM CVT (0900 UTC), the center of Tropical Storm Larry was
located near latitude 12.3 North, longitude 24.8 West. Larry is
moving toward the west near 20 mph (31 km/h). A westward to
west-northwestward motion is expected during the next couple of
days, followed by a turn to the northwest over the weekend.

Maximum sustained winds have increased to near 45 mph (75 km/h)
with higher gusts. Additional strengthening is forecast during the
next few days and Larry is forecast to become a hurricane by late
Thursday or Friday.

Tropical-storm-force winds extend outward up to 60 miles (95 km)
from the center.

The estimated minimum central pressure is 1003 mb (29.62 inches).


HAZARDS AFFECTING LAND
----------------------
None.


NEXT ADVISORY
-------------
Next complete advisory at 200 PM CVT.

$$
Forecaster Stewart

Tropical Storm Larry Discussion Number 3
NWS National Hurricane Center Miami FL AL122021
800 AM CVT Wed Sep 01 2021

Deep convection with cloud tops colder than -80C have increased over
and to the west of the low-level center since the previous advisory.
Subjective satellite intensity estimates at 0600 UTC from TAFB and
SAB were T2.5/35 kt and T3.0/45 kt, while the most recent objective
intensity estimates from UW-CIMSS are T2.8/41 kt from ADT and 37 kt
from SATCON. An average of these intensity estimates support
increasing the advisory intensity to 40 kt, making the cyclone
Tropical Storm Larry. In addition, 0300 UTC and 0700 UTC
observations from ship VRNF3, which recently passed through the
center of Larry, reported a pressure of 1006.8 mb and winds near 25
kt. These data were the basis for the estimated central pressure of
1003 mb, a pressure value that also supports an intensity of 40 kt.

Larry has turned more westward over the past several hours, and the
new motion estimate is 280/17 kt. Larry is expected to move around
the southern and southwestern periphery of the sprawling
Bermuda-Azores ridge for the next 5 days, resulting in a general
west motion for the next 36 hours or so, followed by a turn toward
the west-northwest on Friday, and a northwestward motion over the
weekend and continuing into early next week. There has been a
pronounced westward shift in the track guidance for this cycle, with
the greatest shift coming from the GFS model. Over the past 36
hours, the GFS has shifted its track westward by more than 500 nmi,
and even the latest shift still keeps the GFS model the easternmost
track forecast in the guidance suite. In contrast, the ECMWF and
UKMET models, which lie along the westernmost portion of the
guidance envelope, have been fairly stable. Owing to the westward
shift in the overall guidance envelope, and considering the GFS
solution as an outlier model, the new NHC forecast track has also
been shifted westward, and lies between the NOAA-HCCA
corrected-consensus model to the south, and the tightly packed TVCA
simple-consensus model and FSSE corrected-consensus model to the
north. Given the poor handling of the ridge to the north of Larry by
the GFS, subsequent NHC forecast tracks may have to be shifted
farther west.

Given the improved inner-core wind field based on earlier ASCAT wind
data and reports from ship VRNF3, along with warm sea-surface
temperatures of 28 deg C and light easterly to southeasterly
vertical shear of around 5 kt, steady strengthening is expected for
the next 24 hours or so. By 36 hours when Larry is expected to be a
hurricane and have a well-established and tighter inner-core wind
field and possibly an eye, rapid intensification is forecast, with
Larry becoming a major hurricane by 72 hour. This in large part due
to the massive equatorward upper-level outflow pattern that all
of the global and regional models are forecasting, which is the
same type of outflow pattern that recently occurred with Hurricane
Ida. The new official intensity forecast is above the previous
advisory forecast by about 10 kt at all forecast times, and
conservatively follows an average of the Decay-SHIPS, COAMPS-TC,
FSSE, and ECMWF models. This intensity forecast is near the upper
end of the guidance envelope and is above the other consensus
intensity models.


FORECAST POSITIONS AND MAX WINDS

INIT 01/0900Z 12.3N 24.8W 40 KT 45 MPH
12H 01/1800Z 12.5N 27.5W 50 KT 60 MPH
24H 02/0600Z 12.6N 30.6W 60 KT 70 MPH
36H 02/1800Z 13.1N 33.7W 70 KT 80 MPH
48H 03/0600Z 13.6N 36.8W 85 KT 100 MPH
60H 03/1800Z 14.4N 39.7W 95 KT 110 MPH
72H 04/0600Z 15.5N 42.0W 100 KT 115 MPH
96H 05/0600Z 18.2N 46.9W 105 KT 120 MPH
120H 06/0600Z 21.3N 50.6W 105 KT 120 MPH

$$
Forecaster Stewart

[cycloneye]

BULLETIN
Tropical Storm Larry Advisory Number 4
NWS National Hurricane Center Miami FL AL122021
200 PM CVT Wed Sep 01 2021

...LARRY STRENGTHENS AS IT MOVES QUICKLY WESTWARD THROUGH THE
EASTERN TROPICAL ATLANTIC...


SUMMARY OF 200 PM CVT...1500 UTC...INFORMATION
----------------------------------------------
LOCATION...12.3N 27.6W
ABOUT 275 MI...445 KM SW OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 22 MPH...35 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 200 PM CVT (1500 UTC), the center of Tropical Storm Larry was
located near latitude 12.3 North, longitude 27.6 West. Larry is
moving toward the west near 22 mph (35 km/h), and this general
motion should continue through Thursday. A gradual turn toward the
west-northwest and a decrease in forward speed is expected Thursday
night and Friday.

Maximum sustained winds are now near 50 mph (85 km/h) with higher
gusts. Additional strengthening is forecast, and Larry is expected
to become a hurricane on Thursday.

Tropical-storm-force winds extend outward up to 60 miles (95 km)
from the center.

The estimated minimum central pressure is 1001 mb (29.56 inches).


HAZARDS AFFECTING LAND
----------------------
None.


NEXT ADVISORY
-------------
Next complete advisory at 800 PM CVT.

$$
Forecaster Beven


Tropical Storm Larry Discussion Number 4
NWS National Hurricane Center Miami FL AL122021
200 PM CVT Wed Sep 01 2021

Satellite imagery this morning shows that Larry is becoming better
organized, with curved convective bands increasing around the
center. Various subjective and objective satellite intensity
estimates were in the 35-55 kt range around 12Z, and ASCAT data
near the time showed 40 kt winds. Based on increasing organization
since that time, the initial intensity is increased to 45 kt.

Larry is moving quickly westward, although there is some uncertainty
in the forward speed due to the possibility the center re-formed
during the night. The best estimate of the motion is 270/19 kt. As
noted in the previous advisory, the cyclone is expected to move
around the southern and southwestern periphery of the sprawling
Bermuda-Azores ridge for the next 5 days, resulting in a general
west motion for 24-36 h, followed by a turn toward the
west-northwest and, by 96-120 h, a turn toward the northwest. After
36 h, there is some spread in the track guidance, with the GFS
generally on the right side of the guidance envelope and the UKMET
on the left side, a spread often seen for westward-moving cyclones
south of the Bermuda-Azores high. Due to a more westerly initial
position, the guidance has shifted a little more to the west, and
the new forecast track is again shifted to the west of the previous
track. The new forecast lies a little to the south of the various
consensus models.

Conditions appear favorable for steady to rapid strengthening during
the next 48-60 h due to light shear, a moist environment, and sea
surface temperatures of 27-28C along the forecast track. The new
intensity forecast calls for Larry to become a hurricane in about 24
h and a major hurricane near 60 h. After that time, the global
models suggest the possibility of dry air entrainment, and by 120 h
there is likely to be moderate westerly shear over the cyclone.
Based on this forecast environment and the guidance trends, the
intensity forecast calls for little change in strength from 72-120
h. The new intensity forecast lies near the upper edge of the
intensity guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 01/1500Z 12.3N 27.6W 45 KT 50 MPH
12H 02/0000Z 12.4N 30.4W 55 KT 65 MPH
24H 02/1200Z 12.7N 33.4W 65 KT 75 MPH
36H 03/0000Z 13.2N 36.5W 75 KT 85 MPH
48H 03/1200Z 13.9N 39.2W 90 KT 105 MPH
60H 04/0000Z 15.0N 41.9W 100 KT 115 MPH
72H 04/1200Z 16.2N 44.6W 105 KT 120 MPH
96H 05/1200Z 19.0N 49.5W 105 KT 120 MPH
120H 06/1200Z 22.0N 52.5W 105 KT 120 MPH

$$
Forecaster Beven

[cycloneye]

Tropical Storm Larry Tropical Cyclone Update
NWS National Hurricane Center Miami FL AL122021
530 PM CVT Wed Sep 01 2021

...LARRY GETTING STRONGER OVER THE EASTERN ATLANTIC...

Recent satellite intensity estimates indicate that Larry's maximum
sustained winds have increased to near 65 mph (105 km/h), with
higher gusts.


SUMMARY OF 530 PM CVT...1830 UTC...INFORMATION
----------------------------------------------
LOCATION...12.4N 28.5W
ABOUT 330 MI...530 KM WSW OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...65 MPH...105 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 22 MPH...35 KM/H
MINIMUM CENTRAL PRESSURE...994 MB...29.35 INCHES

$$
Forecaster Beven

[cycloneye]

BULLETIN
Tropical Storm Larry Advisory Number 5
NWS National Hurricane Center Miami FL AL122021
800 PM CVT Wed Sep 01 2021

...LARRY STRENGTHENING QUICKLY AND NOW EXPECTED TO BECOME A
HURRICANE TONIGHT...


SUMMARY OF 800 PM CVT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...12.5N 29.4W
ABOUT 370 MI...595 KM WSW OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 22 MPH...35 KM/H
MINIMUM CENTRAL PRESSURE...991 MB...29.27 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 800 PM CVT (2100 UTC), the center of Tropical Storm Larry was
located near latitude 12.5 North, longitude 29.4 West. Larry is
moving toward the west near 22 mph (35 km/h), and this general
motion should continue through Thursday. A gradual turn toward the
west-northwest and a decrease in forward speed are expected Thursday
night and Friday.

Maximum sustained winds have increased to near 70 mph (110 km/h)
with higher gusts. Steady to rapid strengthening is forecast
during the next couple of days, and Larry is expected to become a
hurricane tonight and a major hurricane by Friday.

Tropical-storm-force winds extend outward up to 70 miles (110 km)
from the center.

The estimated minimum central pressure is 991 mb (29.27 inches).


HAZARDS AFFECTING LAND
----------------------
None.


NEXT ADVISORY
-------------
Next complete advisory at 200 AM CVT.

$$
Forecaster Beven



Tropical Storm Larry Discussion Number 5
NWS National Hurricane Center Miami FL AL122021
800 PM CVT Wed Sep 01 2021

Afternoon satellite imagery indicates that Larry continues to
become better organized, with visible imagery hinting at eye
formation and a partial SSM/IS overpass suggesting that a 37 GHz
convective ring is present around the center. Satellite intensity
estimates are now 65 kt from SAB and 55 kt from TAFB, and the
initial intensity is increased to 60 kt, which is a 30 kt increase
since this time yesterday satisfying the 24-h definition of rapid
intensification.

The initial motion is now 275/19 kt. Larry is expected to move
around the south and southwest sides of a subtropical ridge during
the next five days, with a general westward motion for 24-36 h,
followed by a turn toward the west-northwest and, by 96-120 h, a
turn toward the northwest. The spread in the track guidance after
36 h has decreased a little in the latest model runs. However, the
guidance envelope has again shifted a little to the west. The new
forecast track will also be shifted a little westward, and it lies
on the southern edge of the various consensus models.

Conditions appear favorable for additional rapid intensification
during at the next 36-48 h, and the intensity forecast now calls for
Larry to become a hurricane in less than 12 h and become a major
hurricane in about 48 h. Given current trends, this part of the
intensity forecast could be conservative. There is lower confidence
in the intensity forecast after 48 h. Larry is expected to
encounter somewhat increased shear, and around the 72 h point it is
expected to encounter some dry air. After 96 h, moderate shear is
forecast to continue, but the cyclone is expected to move into a
more moist air mass and over increasing sea surface temperatures.
On top of these factors, there is the good chance that Larry will
have fluctuations in intensity after it becomes a major hurricane
due to eyewall replacement cycles. The intensity guidance basically
keeps a steady intensity from 60-120 h, and the official forecast
follows that trend. However, this part of the intensity forecast is
in the middle of the guidance, and it is possible Larry could be
stronger than forecast during this time.


FORECAST POSITIONS AND MAX WINDS

INIT 01/2100Z 12.5N 29.4W 60 KT 70 MPH
12H 02/0600Z 12.6N 31.8W 70 KT 80 MPH
24H 02/1800Z 13.0N 34.9W 85 KT 100 MPH
36H 03/0600Z 13.7N 38.0W 95 KT 110 MPH
48H 03/1800Z 14.6N 40.9W 100 KT 115 MPH
60H 04/0600Z 15.6N 43.5W 105 KT 120 MPH
72H 04/1800Z 16.9N 46.2W 105 KT 120 MPH
96H 05/1800Z 19.5N 50.5W 105 KT 120 MPH
120H 06/1800Z 22.5N 54.0W 105 KT 120 MPH

$$
Forecaster Beven

[cycloneye]

BULLETIN
Tropical Storm Larry Advisory Number 6
NWS National Hurricane Center Miami FL AL122021
1100 PM AST Wed Sep 01 2021

...LARRY'S STRENGTHENING PAUSES, BUT INTENSIFICATION LIKELY TO
RESUME LATER TONIGHT AND THURSDAY...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...12.8N 30.9W
ABOUT 455 MI...735 KM WSW OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 21 MPH...33 KM/H
MINIMUM CENTRAL PRESSURE...991 MB...29.27 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Tropical Storm Larry was
located near latitude 12.8 North, longitude 30.9 West. Larry is
moving toward the west near 21 mph (33 km/h), and this general
motion should continue through Thursday night. A gradual turn
toward the west-northwest and a decrease in forward speed are
expected Friday and Friday night. A slightly slower west-
northwestward motion is expected on Saturday.

Maximum sustained winds remain near 70 mph (110 km/h) with higher
gusts. Steady to rapid strengthening is forecast during the next
couple of days, and Larry is expected to become a hurricane later
tonight or early Thursday, and a major hurricane Friday or Friday
night.

Tropical-storm-force winds extend outward up to 70 miles (110 km)
from the center.

The estimated minimum central pressure is 991 mb (29.27 inches).


HAZARDS AFFECTING LAND
----------------------
None.


NEXT ADVISORY
-------------
Next complete advisory at 500 AM AST.

$$
Forecaster Brown


Tropical Storm Larry Discussion Number 6
NWS National Hurricane Center Miami FL AL122021
1100 PM AST Wed Sep 01 2021

Larry's strengthening phase appears to have taken a pause this
evening. While an earlier 2055 UTC GMI microwave overpass indicated
that the low-level structure was fairly impressive with a tight
low-level eye-like feature, the deep convection waned briefly, but
has since returned in a band around the eastern portion of the
circulation. The various satellite-based intensity estimates
have an unusually large spread from about 45 to 75 kt this evening.
At the higher end of the estimates are UW/CIMSS ADT T-numbers of
T4.5 and at the lower end were scatterometer wind data showing peak
wind retrievals of about 45 kt. But given the small-inner core
seen in the microwave data, there is likely some undersampling
occuring with the ASCAT instrument. Subjective Dvorak data
T-numbers from both TAFB and SAB were T3.5 (55 kt), and the latest
SATCON estimate is 57 kt. The NHC initial intensity estimate leans
toward the subjective Dvorak numbers and SATCON, and therefore
remains at 60 kt, but there is larger-than-normal uncertainty
regarding the initial intensity at this time.

Larry is moving westward or 275/18 kt. The track forecast
philosophy has not changed this evening. Larry is expected to move
around the south and southwestern portion of a strong mid-level
ridge that is anchored over the east-central Atlantic. This should
steer the tropical cyclone steadily westward to west-northwestward
during the next few days, with a turn toward the northwest by days
4 and 5 as Larry nears the southwestern portion of the ridge. The
latest model envelope is largely unchanged through 120 hours, and
the updated official forecast is very similar to the previous
advisory. Although the track guidance is fairly tightly clustered
there are some differences in how fast Larry will move across the
tropical Atlantic, with the UKMET depicting the fastest forward
speed. The NHC track forecast is slightly slower than the consensus
aids to be in better agreement with the bulk of the guidance and
the GFS ensemble mean.

Conditions are expected to remain favorable for steady to rapid
strengthening. Despite the recent pause in intensification,
Larry is likely to resume strengthening later tonight, and the
short-term portion of the intensity forecast is unchanged from
before. Larry is forecast to become a hurricane by Thursday
morning, and a major hurricane in 36-48 hours. That portion of
the intensity forecast is in good agreement with the SHIPS guidance
and is supported by the global model guidance which significantly
deepen Larry over the next couple of days. After that time, there
are some mixed signals on the amount of shear over the system
with the GFS-based SHIPS guidance predicting moderate shear and some
dry air, while the ECMWF-based SHIPS model diagnoses more favorable
conditions. For now, the NHC intensity forecast shows a peak
slightly higher than before by 72 hours, and then indicates little
overall change in strength thereafter as some fluctuations in
intensity could occur due to eyewall replacement cycles. The latter
portion of the forecast is in best agreement with the HFIP corrected
consensus aid.


FORECAST POSITIONS AND MAX WINDS

INIT 02/0300Z 12.8N 30.9W 60 KT 70 MPH
12H 02/1200Z 13.0N 33.3W 70 KT 80 MPH
24H 03/0000Z 13.6N 36.5W 85 KT 100 MPH
36H 03/1200Z 14.2N 39.5W 95 KT 110 MPH
48H 04/0000Z 15.1N 42.2W 100 KT 115 MPH
60H 04/1200Z 16.2N 44.8W 105 KT 120 MPH
72H 05/0000Z 17.4N 47.3W 110 KT 125 MPH
96H 06/0000Z 20.1N 51.4W 110 KT 125 MPH
120H 07/0000Z 22.9N 55.0W 110 KT 125 MPH

$$
Forecaster Brown

[cycloneye]

Hurricane Larry Discussion Number 7
NWS National Hurricane Center Miami FL AL122021
500 AM AST Thu Sep 02 2021

Larry's cloud pattern has gradually become better organized, with
deep convection increasing in coverage and intensity near the
center and a banding-type eye trying to form. Upper-level outflow
is most prominent over the western and northern portions of the
circulation. A well-defined low-level eye was apparent on an
AMSR-2 image from a few hours ago. Dvorak final T- and Current
Intensity-numbers from both TAFB and SAB are 4.0/4.0, corresponding
to an intensity of 65 kt. Based on these estimates, Larry is
upgraded to a hurricane, the fifth of the 2021 Atlantic season.

The hurricane is moving just slightly north of west, or 280/17 kt.
There are no important changes to the track forecast scenario from
the previous advisory. Larry is likely to move along the southern
and southwestern periphery of a strong deep-layer subtropical high
pressure area over the east-central Atlantic during the next few
days. This should result in a gradual turn toward the
west-northwest during the next 48-72 hours. A turn toward the
northwest is likely in 4-5 days as the system approaches a weakness
in the ridge. The track models are fairly well clustered on this
future direction of motion with some differences in forward speed.
The official track forecast is quite similar to the previous one
and is also very close to the latest dynamical model consensus,
TVCA.

Larry is expected to remain in an environment conducive for
strengthening over the next few days, with marginally warm
SSTs, low vertical shear, and surrounded by broad-scale anticyclonic
upper-level flow. Therefore, strengthening is likely, and the
official forecast calls for Larry to become a major hurricane in 48
hours or so. Some fluctuations in intensity due to eyewall
replacements are possible around and after that time. Late in the
forecast period, slightly drier air in the environment could limit
further intensification. The official intensity forecast is close
to the latest NOAA corrected consensus, HCCA, guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 02/0900Z 13.0N 32.3W 65 KT 75 MPH
12H 02/1800Z 13.4N 34.7W 75 KT 85 MPH
24H 03/0600Z 14.0N 37.9W 85 KT 100 MPH
36H 03/1800Z 14.8N 40.9W 95 KT 110 MPH
48H 04/0600Z 15.8N 43.6W 100 KT 115 MPH
60H 04/1800Z 16.9N 46.1W 105 KT 120 MPH
72H 05/0600Z 18.3N 48.3W 110 KT 125 MPH
96H 06/0600Z 20.9N 52.1W 115 KT 130 MPH
120H 07/0600Z 23.8N 55.4W 110 KT 125 MPH

$$
Forecaster Pasch

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 8
NWS National Hurricane Center Miami FL AL122021
1100 AM AST Thu Sep 02 2021

...LARRY IS LARGER AND A BIT STRONGER...
...STEADY TO RAPID INTENSIFICATION LIKELY IN THE COMING DAYS...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...13.5N 34.2W
ABOUT 660 MI...1065 KM W OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 17 MPH...28 KM/H
MINIMUM CENTRAL PRESSURE...985 MB...29.09 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Hurricane Larry was located
near latitude 13.5 North, longitude 34.2 West. Larry is moving
toward the west near 17 mph (28 km/h). A gradual turn towards the
west-northwest with a decrease in forward speed are expected over
the next few days.

Maximum sustained winds have increased to near 80 mph (130 km/h)
with higher gusts. Steady to rapid strengthening is forecast during
the next couple of days, and Larry is expected to become a a major
hurricane by Friday night.

Hurricane-force winds extend outward up to 15 miles (30 km) from the
center. Recent satellite wind data indicates that the
tropical-storm-force wind radii are expanding and now extend outward
up to 160 miles (260 km).

The estimated minimum central pressure is 985 mb (29.09 inches).


HAZARDS AFFECTING LAND
----------------------
None.


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Papin


Hurricane Larry Discussion Number 8
NWS National Hurricane Center Miami FL AL122021
1100 AM AST Thu Sep 02 2021

Larry continues to gradually become better organized this morning,
with a small but cold CDO near the estimated center, and well
defined curved bands rotating completely around.
Unfortunately, there have not been any recent microwave
passes over the center in the last 6-9 hours. However, I
did receive a helpful ASCAT-B pass at 1128 UTC which indicated that
while the inner core remains quite small, the 34-kt wind radii have
expanded dramatically in all quadrants. The most recent Dvorak
subjective intensity estimates were both CI 4.0/65 kt from SAB and
TAFB. However, the objective intensity estimates from SATCON and
ADT are higher, at 70 kt and 77 kt respectively. Thus, the current
intensity of Larry was nudged upward to 70 kt for this advisory.

The hurricane's heading has changed little this morning, estimated
at 280/15 kt. There also remains little change to the forecast track
reasoning. A dominant mid-level ridge is located north of Larry
and should maintain the hurricane on a west to west-northwest
heading over the next 72 hours. The track guidance is in excellent
agreement over this time period. After 72 hours, a bit more track
guidance spread begins to take shape, which appears related to the
evolution of the the steering ridge orientation. For example, the
most recent GFS run begins a more pronounced rightward bend, as the
ridge becomes positioned northeast of the tropical cyclone. In
contrast, the ECMWF and a number of its left-leaning ensemble
members maintain more ridging directly north of Larry, keeping the
hurricane on a more leftward track with only a gradual bend to the
west-northwest and northwest. These differences notwithstanding, the
consensus aids has changed little from the previous forecast cycle,
and the NHC forecast track is nearly identical to the previous
track. This track lies very close to the HCCA consensus aid, which
favors a track solution a bit closer to the ECMWF versus the GFS.

Larry's environmental conditions appear very favorable for
additional intensification over the next 60-72 hours. In fact, the
primarily forecast challenge relates to how Larry's core structure
evolves over the next several days. Right now, the inner-core and
hurricane-force wind radii are very small relative to the expanding
tropical-storm-force wind field around the storm. Thus, it appears
likely that Larry will undergo some form of an eyewall replacement
cycle (ERC) in the next 12 to 24 hours, which may slow down the
short term intensification rate. However, once this cycle is
complete, very light easterly vertical wind shear between 2-8 kt,
abundant mid-level moisture, and sufficently warm sea-surface
temperatures between 27-28 C should favor steady to rapid
intensification. The latest NHC intensity forecast now calls for a
peak intensity of 120 kt in roughly 72 hours, which is a faster and
slightly higher peak than the prior forecast. Afterwards, the
guidance is a bit conflicted. The GFS-based SHIPS continues to
suggests low vertical wind shear through the end of the forecast
period. However, the ECMWF-based SHIPS shows much higher
southwesterly vertical wind shear beginning in 84 hours as Larry
also moves into a drier environment. It is also possible additional
ERCs may occur in the latter portion of this forecast, resulting in
additional intensity fluctuations. For these reasons, the intensity
forecast at the end of the period shows some modest weakening. This
intensity forecast is a bit higher than the HCCA corrected consensus
aid, but remains lower than some of the more aggressive guidance
(COAMPS-TC, the experimental HAFS-B).

FORECAST POSITIONS AND MAX WINDS

INIT 02/1500Z 13.5N 34.2W 70 KT 80 MPH
12H 03/0000Z 13.8N 36.7W 75 KT 85 MPH
24H 03/1200Z 14.4N 39.7W 85 KT 100 MPH
36H 04/0000Z 15.3N 42.6W 95 KT 110 MPH
48H 04/1200Z 16.5N 45.2W 105 KT 120 MPH
60H 05/0000Z 17.9N 47.6W 115 KT 130 MPH
72H 05/1200Z 19.2N 49.7W 120 KT 140 MPH
96H 06/1200Z 21.8N 53.1W 115 KT 130 MPH
120H 07/1200Z 24.6N 56.0W 110 KT 125 MPH

$$
Forecaster Papin

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 9
NWS National Hurricane Center Miami FL AL122021
500 PM AST Thu Sep 02 2021

...LARRY LIKELY TO BECOME A LARGE AND POWERFUL HURRICANE...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...13.7N 35.8W
ABOUT 765 MI...1235 KM W OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...985 MB...29.09 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Hurricane Larry was located
near latitude 13.7 North, longitude 35.8 West. Larry is moving
toward the west near 18 mph (30 km/h). A gradual turn towards the
west-northwest with a decrease in forward speed is expected over the
next few days. A turn to the northwest is then expected by early
next week.

Maximum sustained winds are near 80 mph (130 km/h) with higher
gusts. Significant to possibly rapid intensification is forecast
during the next couple of days, and Larry is expected to become a
major hurricane tomorrow night.

Hurricane-force winds extend outward up to 25 miles (35 km) from the
center and tropical-storm-force winds extend outward up to 160 miles
(260 km).

The estimated minimum central pressure is 985 mb (29.09 inches).


HAZARDS AFFECTING LAND
----------------------
None.


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Papin



Hurricane Larry Discussion Number 9
NWS National Hurricane Center Miami FL AL122021
500 PM AST Thu Sep 02 2021

This afternoon, Larry's appearance has evolved from a small central
dense overcast to a tightly coiled spiral banding pattern, with
these bands wrapping into the estimated center. I finally received a
useful SSMIS microwave overpass at 1857 UTC which provided evidence
that Larry could be undergoing an eyewall replacement cycle (ERC).
The imagery suggests a large outer eyewall is taking shape on the
low-level 37-GHz channel, while an inner eyewall fragment is still
seen on the mid-level 91-GHz channel. Despite these structural
changes, the 1800 UTC subjective Dvorak estimates from TAFB and SAB
were unchanged from this morning at CI 4.0/65 kt. In addition, the
latest objective intensity estimates from SATCON and ADT have only
varied slightly at 73 kt and 74 kt respectively. Taking a blend of
the subjective and objective estimates still yields 70 kt for this
advisory.

Larry continues to move just north of due west, with the latest
motion estimated at 280/16 kt. There is not much new to report with
the track reasoning, with a large mid-level ridge currently north of
Larry expected to steer the hurricane to the west or west-northwest
over the next 2-3 days. Over time, the ridge axis is forecast to
slowly shift further northeast of Larry's position, allowing the
hurricane to gradually gain a more rightward component of motion by
the end of the forecast period. In general, the track guidance
remains tightly clustered for the first 2-3 days. There was a
notable shift west in the latest 12z GFS deterministic track, while
the 12z ECMWF shifted ever so slightly right. A quick look at the
12z ECMWF ensemble guidance reveals that the deterministic run is a
bit to the northeast of the ensemble mean. The latest NHC track has
been shifted slightly to the south and west of the previous track,
following the reliable HFIP corrected consensus aid (HCCA) which
also shifted a bit south and west this cycle.

Once Larry completes the ongoing ERC, significant or even rapid
intensification is anticipated. The short-term intensity forecast
has been raised a bit more, since it appears more likely the present
ERC will finish in the next 6-12 h. The latest NHC intensity
forecast now makes Larry a major hurricane by tomorrow night, with
further intensification up to Category 4 intensity anticipated by
Sunday. Once again, there remains some discrepancy in the vertical
wind shear forecast between the GFS- and ECMWF-based SHIPS guidance,
with the ECMWF forecasting significantly more southwesterly shear
beyond 72 hours. Both guidance tools also indicate a decrease in
mid-level relative humidity which, if the shear materializes, could
disrupt Larry's inner core structure. Thus, the NHC intensity
forecast still shows gradual weakening from 72 to 120 hours. The
latest intensity forecast is just a hair above HCCA in the short
term, with the intensity forecast most closely following the latest
COAMPS-TC (CTCI) guidance in the first three days.

FORECAST POSITIONS AND MAX WINDS

INIT 02/2100Z 13.7N 35.8W 70 KT 80 MPH
12H 03/0600Z 14.0N 38.4W 80 KT 90 MPH
24H 03/1800Z 14.7N 41.3W 95 KT 110 MPH
36H 04/0600Z 15.7N 43.9W 105 KT 120 MPH
48H 04/1800Z 16.9N 46.3W 110 KT 125 MPH
60H 05/0600Z 18.3N 48.6W 120 KT 140 MPH
72H 05/1800Z 19.7N 50.6W 120 KT 140 MPH
96H 06/1800Z 22.2N 54.0W 115 KT 130 MPH
120H 07/1800Z 25.1N 57.0W 110 KT 125 MPH

$$
Forecaster Papin

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 10
NWS National Hurricane Center Miami FL AL122021
1100 PM AST Thu Sep 02 2021

...LARRY A LITTLE STRONGER...
...RISK OF RIP CURRENTS FROM LARRY'S SWELLS INCREASES FOR THE
LESSER ANTILLES ON SUNDAY...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...14.1N 37.5W
ABOUT 875 MI...1410 KM W OF THE SOUTHERNMOST CABO VERDE ISLANDS
ABOUT 1630 MI...2620 KM E OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 20 MPH...31 KM/H
MINIMUM CENTRAL PRESSURE...985 MB...29.09 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Hurricane Larry was located
near latitude 14.1 North, longitude 37.5 West. Larry is moving
toward the west near 20 mph (31 km/h), and this motion is expected
to continue through Friday morning. A turn toward the
west-northwest is expected later on Friday, followed by a turn
toward the northwest on Sunday.

Maximum sustained winds have increased to near 85 mph (140 km/h)
with higher gusts. Additional strengthening is forecast during the
next few days, and Larry could become a major hurricane by Friday
night.

Hurricane-force winds extend outward up to 25 miles (35 km) from the
center and tropical-storm-force winds extend outward up to 150 miles
(240 km).

The estimated minimum central pressure is 985 mb (29.09 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Larry are expected to reach the Lesser
Antilles on Sunday. These swells are likely to cause
life-threatening surf and rip current conditions. Please consult
products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 500 AM AST.

$$
Forecaster Berg




Hurricane Larry Discussion Number 10
NWS National Hurricane Center Miami FL AL122021
1100 PM AST Thu Sep 02 2021

A series of SSMIS microwave passes earlier this afternoon indicated
that Larry may have been starting an eyewall replacement. However,
the last pass at 2058 UTC suggested that the eyewall replacement
failed, with the western part of the outer eyewall being eroded,
possibly by some modest mid-level shear and some dry air, and the
tighter inner eyewall trying to re-establish itself. As a result,
the convective pattern has reverted back to a small Central Dense
Overcast. Subjective Dvorak intensity estimates are now T4.5/77 kt
from TAFB and T4.0/65 kt from SAB, and the latest objective
estimates range from 72 to 78 kt. Overall these numbers have risen
a bit, and Larry's maximum winds are now estimated to be 75 kt.

Larry continues moving toward the west but perhaps slightly faster
(280/17 kt). There is no change to the track forecast reasoning.
A fairly stagnant pattern consisting of a strong mid-level high
over the central Atlantic and broad-scale troughing over the
eastern United States and western Atlantic should persist through
the 5-day forecast period. Larry is therefore forecast to turn
toward the west-northwest on Friday and then take on a northwest
heading Sunday through Tuesday while it moves around the
southwestern periphery of the high. The updated NHC track forecast
lies right along the previous forecast and is very close to the
various consensus aids.

Low shear, gradually increasing sea surface temperatures, and the
potential for an upper-level outflow jet to form north of the
hurricane during the next 24-48 hours should support continued
strengthening. During the first 48 hours, the NHC forecast shows a
steady increase of 10 kt every 24 hours, close to the HCCA
consensus aids and near the top of the guidance envelope. By days
3 and 4, there continue to be indications that increasing westerly
or northwesterly shear could become a factor, and the NHC forecast
therefore shows a leveling off of the intensity, with some slight
weakening by the end of the forecast period. If Larry becomes a
strong hurricane, eyewall replacements would also be a possibility,
which would likely lead to difficult-to-forecast fluctuations in
intensity.

The leading swell front from Larry is expected to reach the Lesser
Antilles on Sunday, increasing the risk of life-threatening rip
currents and surf conditions on those islands early next week.
Large swells are likely to spread to areas surrounding the western
Atlantic later in the week as well.


FORECAST POSITIONS AND MAX WINDS

INIT 03/0300Z 14.1N 37.5W 75 KT 85 MPH
12H 03/1200Z 14.5N 39.9W 85 KT 100 MPH
24H 04/0000Z 15.3N 42.6W 95 KT 110 MPH
36H 04/1200Z 16.4N 45.2W 105 KT 120 MPH
48H 05/0000Z 17.6N 47.5W 115 KT 130 MPH
60H 05/1200Z 19.0N 49.7W 120 KT 140 MPH
72H 06/0000Z 20.4N 51.8W 120 KT 140 MPH
96H 07/0000Z 22.9N 55.0W 115 KT 130 MPH
120H 08/0000Z 25.9N 58.0W 110 KT 125 MPH

$$
Forecaster Berg

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 11
NWS National Hurricane Center Miami FL AL122021
500 AM AST Fri Sep 03 2021

...LARRY SLOWLY STRENGTHENING...
...RISK OF RIP CURRENTS AND HIGH SURF FROM LARRY'S SWELLS INCREASES
FOR THE LESSER ANTILLES ON SUNDAY...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...14.6N 38.9W
ABOUT 970 MI...1560 KM W OF THE SOUTHERNMOST CABO VERDE ISLANDS
ABOUT 1530 MI...2460 KM E OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 20 MPH...31 KM/H
MINIMUM CENTRAL PRESSURE...982 MB...29.00 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Hurricane Larry was located
near latitude 14.6 North, longitude 38.9 West. Larry is moving
toward the west-northwest near 20 mph (31 km/h) and this motion is
expected during the next few days. A turn to the northwest is
forecast by early next week.

Maximum sustained winds have increased to near 90 mph (150 km/h)
with higher gusts. Additional strengthening is forecast during the
next few days, and Larry could become a major hurricane by tonight.

Hurricane-force winds extend outward up to 25 miles (35 km) from the
center and tropical-storm-force winds extend outward up to 150 miles
(240 km).

The estimated minimum central pressure is 982 mb (29.00 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Larry are expected to reach the Lesser
Antilles on Sunday. These swells are likely to cause
life-threatening surf and rip current conditions. Please consult
products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Cangialosi


Hurricane Larry Discussion Number 11
NWS National Hurricane Center Miami FL AL122021
500 AM AST Fri Sep 03 2021

Larry continues to gradually become better organized. Satellite
images show a fairly compact central dense overcast feature with an
eye occasionally evident. Beyond the inner core, banding features
are gradually becoming more distinct, especially to the south of the
center. The latest Dvorak classifications at 0600 UTC was 4.5/77 kt
from TAFB and SAB, and based on those estimates and the improving
trend, the initial intensity is nudged upward to 80 kt.

Larry is moving west-northwestward at 17 kt. There has been no
change to the track forecast reasoning. A continued westward to
west-northwestward motion is expected on Friday and through the
weekend as the hurricane remains on the south side of a mid-level
ridge. By early next week, Larry is expected to slow down and turn
northwestward when it reaches the southwestern periphery of the
ridge. The models are in fairly good agreement, and the NHC track
forecast lies near the middle of the guidance envelope. This
forecast is largely an update of the previous one.

The environmental factors appear favorable for steady strengthening
during the next few days with wind shear remaining low and mid-level
moisture fairly high. The only slightly negative factor is
marginally warm 26-27 deg C waters that Larry will be moving over
during the next couple of days, which should prevent rapid
intensification. All of the models are in general agreement that
Larry will become a major hurricane in a day or so with continued
strengthening through day 3, and the NHC intensity forecast follows
suit. Some weakening is shown by the end of the forecast period
when the wind shear could increase a little. This forecast is very
similar to the previous one and lies near the high end of the
guidance envelope. It should be noted that eyewall replacement
cycles are possible, which could cause intensity fluctuations that
are challenging to predict.

The leading swell front from Larry is expected to reach the Lesser
Antilles on Sunday, increasing the risk of life-threatening rip
currents and high surf conditions on those islands early next week.
Large swells are likely to spread to areas surrounding the western
Atlantic later in the week as well.


FORECAST POSITIONS AND MAX WINDS

INIT 03/0900Z 14.6N 38.9W 80 KT 90 MPH
12H 03/1800Z 15.2N 41.1W 90 KT 105 MPH
24H 04/0600Z 16.2N 43.8W 100 KT 115 MPH
36H 04/1800Z 17.3N 46.2W 105 KT 120 MPH
48H 05/0600Z 18.6N 48.5W 115 KT 130 MPH
60H 05/1800Z 19.8N 50.5W 120 KT 140 MPH
72H 06/0600Z 21.1N 52.5W 120 KT 140 MPH
96H 07/0600Z 23.8N 55.8W 115 KT 130 MPH
120H 08/0600Z 27.1N 58.9W 110 KT 125 MPH

$$
Forecaster Cangialosi

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 12
NWS National Hurricane Center Miami FL AL122021
1100 AM AST Fri Sep 03 2021

...LARRY APPEARS POISED TO INTENSIFY FURTHER...
...RISK OF RIP CURRENTS AND HIGH SURF FROM LARRY'S SWELLS INCREASES
FOR THE LESSER ANTILLES BY SUNDAY...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...14.8N 40.7W
ABOUT 1090 MI...1750 KM W OF THE SOUTHERNMOST CABO VERDE ISLANDS
ABOUT 1410 MI...2270 KM E OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...981 MB...28.97 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Hurricane Larry was located
near latitude 14.8 North, longitude 40.7 West. Larry is moving
toward the west-northwest near 16 mph (26 km/h) and this motion is
expected to continue over the next few days. A turn to the
northwest is forecast by early next week.

Maximum sustained winds are near 90 mph (150 km/h) with higher
gusts. Additional strengthening is forecast during the
next few days, and Larry is forecast to become a major hurricane
this weekend.

Hurricane-force winds extend outward up to 30 miles (45 km) from the
center and tropical-storm-force winds extend outward up to 150 miles
(240 km).

The estimated minimum central pressure is 981 mb (28.97 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Larry are expected to reach the Lesser
Antilles on Sunday. These swells are likely to cause
life-threatening surf and rip current conditions. Please consult
products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Papin




Hurricane Larry Discussion Number 12
NWS National Hurricane Center Miami FL AL122021
1100 AM AST Fri Sep 03 2021

Larry continues to have the presentation of a hurricane that is
gradually becoming better organized. Its structure this morning
consists of well defined spiral banding around a somewhat asymmetric
central dense overcast. More recently, a warm spot appears to be
forming on both infrared and visible satellite channels which could
foreshadow the development of a better-defined eye, as hinted at on
an earlier 0934 UTC SSMIS microwave pass. The most recent subjective
Dvorak classifications at 1200 UTC were still CI 4.5/77 kt from TAFB
and SAB. Interestingly, the objective satellite estimates from ADT
and SATCON remain on the lower side, though these seem conservative
given the structural improvements seen on recent satellite images.
Favoring the subjective estimates, the initial intensity is being
maintained at 80 kt for this advisory.

Larry continues to move to the west-northwest at 285/14 kt. A
prominent mid-level ridge located to the north of the hurricane is
expected to continue this heading over the next 24 to 36 hours,
though with a gradual decrease in forward speed. As Larry continues
to move west-northwest, the ridge axis will gradually re-position to
the northeast of the tropical cyclone, providing an avenue for the
hurricane to begin gaining more latitude. Starting around 72 hours,
a bit more cross-track spread begins to emerge in the track
guidance, related to both how much ridging remains directly poleward
of Larry, and also the outer-core size of the tropical cyclone
itself. For example, the most recent GFS run shifts most of the
ridging to the east of Larry and also expands the outer radius of
cyclone dramatically, helping to widen the poleward weakness
allowing a more northward track by 120 hours. By contrast, the ECMWF
maintains a more compact hurricane in the mid-levels, and maintains
more mid-level ridging to the north of the cyclone. These
differences in the ECMWF allow a bit more of a westward track closer
to the Island of Bermuda. For now, the latest NHC track forecast is
in between these solutions, though with a slight preference towards
the ECMWF, which is also close to the latest HCCA consensus aid
forecast. This track forecast is quite similar to the previous
forecast. Given the track uncertainty by day 5, it is too soon to
determine what impacts Larry may pose to the Island of Bermuda, but
interests there should monitor updates in the forecast in the
subsequent days.

Larry remains embedded in a favorable environment for
intensification, with low vertical wind shear under 10 kt and a
sufficently moist mid-level environment. However, the hurricane has
had difficulty closing off its inner-core structure, which might be
preventing more rapid development from taking place. Assuming its
inner core becomes better established, Larry is expected to
intensity at a decent clip over the next 36-48 hours, and is
forecast to become a major hurricane this weekend with a peak
intensity of 120 kt by Monday. Afterwards, both the ECMWF-SHIPS
guidance and latest HWRF run suggest that westerly vertical wind
shear, from an upper-level mid-oceanic trough positioned northwest
of Larry, could begin to undercut the favorable upper-level
environment of the large tropical cyclone. Thus, some gradual
weakening is shown from days 3-5 in the NHC intensity forecast. This
latest forecast is quite similar to the previous one and is on the
upper-end of the guidance envelope, though still not as high as the
most recent COAMPS-TC and experimental HAFS-B runs. This intensity
forecast also does not account for possible eyewall replacement
cycles, which could cause additional intensity fluctuations that are
difficult to predict several days in advance.

Significant ocean swells generated by the large wind field of Larry
are expected to reach the Lesser Antilles on Sunday, increasing the
risk of life-threatening rip currents and high surf conditions on
those islands early next week. Large swells are likely to spread to
areas surrounding the western Atlantic later in the week as well.


FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 14.8N 40.7W 80 KT 90 MPH
12H 04/0000Z 15.4N 42.8W 90 KT 105 MPH
24H 04/1200Z 16.5N 45.3W 100 KT 115 MPH
36H 05/0000Z 17.6N 47.6W 110 KT 125 MPH
48H 05/1200Z 19.0N 49.8W 115 KT 130 MPH
60H 06/0000Z 20.2N 51.8W 120 KT 140 MPH
72H 06/1200Z 21.4N 53.6W 120 KT 140 MPH
96H 07/1200Z 24.2N 56.9W 115 KT 130 MPH
120H 08/1200Z 27.8N 60.0W 105 KT 120 MPH

$$
Forecaster Papin

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 13
NWS National Hurricane Center Miami FL AL122021
500 PM AST Fri Sep 03 2021

...LARRY INTENSIFIES INTO A CATEGORY 2 HURRICANE...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...15.0N 42.0W
ABOUT 1175 MI...1890 KM W OF THE SOUTHERNMOST CABO VERDE ISLANDS
ABOUT 1320 MI...2125 KM E OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...978 MB...28.88 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Hurricane Larry was located
near latitude 15.0 North, longitude 42.0 West. Larry is moving
toward the west-northwest near 16 mph (26 km/h) and this motion is
expected to continue over the weekend. A turn to the
northwest is forecast by early next week.

Maximum sustained winds have increased to near 100 mph (155 km/h)
with higher gusts. Additional strengthening is forecast during the
next few days, and Larry is forecast to become a major hurricane
this weekend.

Hurricane-force winds extend outward up to 35 miles (55 km) from the
center and tropical-storm-force winds extend outward up to 150 miles
(240 km).

The estimated minimum central pressure is 978 mb (28.88 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Larry are expected to reach the Lesser
Antilles on Sunday. Significant swells will likely reach Bermuda
and the eastern United States coastline after Labor Day. These
swells are likely to cause life-threatening surf and rip current
conditions. Please consult products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Papin




Hurricane Larry Discussion Number 13
NWS National Hurricane Center Miami FL AL122021
500 PM AST Fri Sep 03 2021

Over the course of the day, Larry's appearance has become more
impressive. The eye has been gradually becoming better defined on
visible satellite imagery as the center cloud top temperature has
been warming on the infrared channel. Several microwave passes have
been received since the last advisory. The most recent pass at 1900
UTC suggested the eye and surrounding eyewall convection is becoming
better defined, though still weaker on the east side. 1800
UTC subjective Dvorak classifications were still both CI 4.5/77 kt
from TAFB and SAB. However, the objective satellite estimates have
been rising quickly, with the most recent UW-CIMSS SATCON estimate
up to 84 kt. Thus, the NHC advisory intensity has been raised to 85
kt for this advisory, making Larry a category 2 hurricane.

Larry's motion has remained fairly steady to the west-northwest
throughout the day, at 285/14 kt. The latest track reasoning remains
unchanged, with Larry being steered to the west-northwest around the
southern periphery of an expansive mid-level ridge centered north
of the hurricane. This ridge axis will gradually become oriented to
the northeast of Larry with time, allowing the tropical cyclone to
gradually gain more latitude. Because the ridge is quite large, even
as its axis shifts eastward, a portion of the ridge will still
remain to the north of the storm. The end result is that Larry
should only slowly gain a more poleward component of motion as the
system also gradually slows down. While the track guidance spread
remains small for the first 48-60 hours of the forecast, a bit more
longitudinal spread becomes apparent thereafter, which appears
related to how much mid-level ridging remains poleward of the
cyclone. The latest 12z ECMWF run has a distinctly stronger ridge,
oriented more poleward in comparison to the 12z GFS run. Thus, it is
not surprising to see that the ECMWF track is a bit further west and
slower than the GFS. The latest NHC track forecast this cycle was
also adjusted a bit slower, following the TVCN and HCCA consensus
aids. However, it is interesting to note the latest 12z ECMWF
ensembles are even slower than this track forecast, and future
slower adjustments may be needed if these track solutions verify. It
remains too soon to determine what impacts Larry may pose to the
Island of Bermuda, but interests there should monitor updates in the
forecast in the subsequent days.

With the recent improvement in Larry's structure on satellite
imagery, the hurricane may be starting another rapid intensification
(RI) cycle, as suggested by the high RI probabilities given in the
DTOPS guidance. However, the earlier microwave data also suggested
that there were a lot of concentric bands outside of the primary
eyewall, and it is not out of the question that another eyewall
replacement cycle could begin in the next 24-36 hours. Instead
of attempting to forecast these often stochastic processes, the
latest NHC intensity forecast will instead show a healthy rate of
deepening over the next several days, now taking Larry to 120 kt in
48 hours. Afterwards, there still remain questions as to how much
the vertical wind shear will increase over Larry, with the
ECMWF-SHIPS indicating higher shear that could affect Larry's
inner-core structure, while the GFS-SHIPS showing much lower shear.
Warmer sea-surface temperatures also await the hurricane in the
60-96 hour period. Due to these competing factors, the intensity
forecast during this period will only show very gradual weakening.
The latest NHC intensity forecast remains on the high end of the
guidance, but still remains lower than the higher HAFS-B and
COAMPS-TC models. It should be noted that the majority of the
guidance also shows Larry becoming a very large hurricane, with a
significant expansion of the 34-, 50-, and 64-kt wind radii also
forecast.

Significant ocean swells generated by the increasingly large wind
field of Larry are expected to reach the Lesser Antilles on Sunday,
increasing the risk of life-threatening rip currents and high surf
conditions on those islands early next week. Large swells are likely
to spread to areas surrounding the western Atlantic later in the
week as well.

FORECAST POSITIONS AND MAX WINDS

INIT 03/2100Z 15.0N 42.0W 85 KT 100 MPH
12H 04/0600Z 15.8N 44.1W 95 KT 110 MPH
24H 04/1800Z 16.9N 46.5W 105 KT 120 MPH
36H 05/0600Z 18.1N 48.7W 110 KT 125 MPH
48H 05/1800Z 19.4N 50.8W 120 KT 140 MPH
60H 06/0600Z 20.7N 52.8W 120 KT 140 MPH
72H 06/1800Z 21.9N 54.5W 115 KT 130 MPH
96H 07/1800Z 24.7N 57.6W 115 KT 130 MPH
120H 08/1800Z 28.7N 60.5W 105 KT 120 MPH

$$
Forecaster Papin

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 14
NWS National Hurricane Center Miami FL AL122021
1100 PM AST Fri Sep 03 2021

...LARRY LUNGES TO MAJOR HURRICANE INTENSITY...
...DANGEROUS SURF AND RIP CURRENTS EXPECTED TO DEVELOP ALONG MANY
WESTERN ATLANTIC SHORES NEXT WEEK...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...15.5N 43.3W
ABOUT 1230 MI...1980 KM E OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...965 MB...28.50 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Hurricane Larry was located
near latitude 15.5 North, longitude 43.3 West. Larry is moving
toward the west-northwest near 16 mph (26 km/h), and this motion is
expected to continue through late Saturday. A motion toward the
northwest at a slower forward speed is forecast to begin Sunday
morning and continue through Tuesday.

Maximum sustained winds have increased to near 115 mph (185 km/h)
with higher gusts. Larry is a category 3 hurricane on the
Saffir-Simpson Hurricane Wind Scale. Additional strengthening is
forecast over the next day or two, and Larry is expected to remain
at major hurricane strength through the early part of next week.

Hurricane-force winds extend outward up to 35 miles (55 km) from the
center and tropical-storm-force winds extend outward up to 150 miles
(240 km).

The estimated minimum central pressure is 965 mb (28.50 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Larry are expected to reach the Lesser
Antilles on Sunday, and will continue to spread westward to
portions of the Greater Antilles, the Bahamas, and Bermuda Monday
and Tuesday. Significant swells will likely reach the eastern
United States coastline after Labor Day. These swells are likely to
cause life-threatening surf and rip current conditions. Please
consult products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 500 AM AST.

$$
Forecaster Berg




Hurricane Larry Discussion Number 14
NWS National Hurricane Center Miami FL AL122021
1100 PM AST Fri Sep 03 2021

Larry has had a distinct but slightly ragged 15 n mi wide eye
during the past few hours, while convective cloud tops within the
eyewall have been gradually cooling. Intensity estimates have
responded, somewhat significantly, to the improved structure, and
TAFB and SAB Dvorak fixes at 0000 UTC were T5.5/102 kt and T5.0/90
kt, respectively. In addition, objective UW-CIMSS ADT and SATCON
estimates are near 105 kt. Larry has become a major hurricane, the
third of the Atlantic season, with estimated 100-kt sustained winds.

The hurricane is located due south of a mid-tropospheric high
centered over the central Atlantic, and continues to move toward
the west-northwest (285/14 kt). Larry is generally expected to move
around the southwestern periphery of the high, turning northwestward
at a slower speed by Sunday and then north-northwestward by
Wednesday as a deep-layer trough moves eastward across the eastern
United States. There is fairly high confidence in the track
forecast, with model guidance showing a below- to near-normal amount
of spread through day 5. The new NHC track forecast is right along
the forecast from the previous advisory through day 3, and then
nudged slightly westward on days 4 and 5. It should be noted that a
few of the consensus aids, including HCCA, are still a little bit
west of the official forecast at day 5, which might portend
additional westward nudges in future advisories.

By strict definition, Larry hasn't quite rapidly intensified since
this time yesterday, but it has still strengthened quickly over
waters that are considered only marginally warm (26-27 degrees
Celsius). For the next couple of days, low shear, higher oceanic
heat content, and a more unstable environment should favor
additional intensification. However, there are still indications
that Larry could run into an environment of higher shear and less
upper-level divergence in 2-3 days as it approaches a
mid-/upper-level trough currently located north and northeast of
the Leeward Islands. In addition, internal processes within the
hurricane's core itself, such as eyewall replacement cycles, could
affect the intensity. In light of all these factors, the NHC
intensity forecast relies on persistence to show additional
strengthening during the next 36 hours, and then holds Larry steady
through 60 hours at an intensity that is near the upper end of the
guidance. Very gradual weakening is anticipated on days 3 through
5 while Larry heads in the direction of higher latitudes, yet the
hurricane is forecast to remain at major hurricane intensity for
the entire 5-day forecast period.

Significant ocean swells generated by Larry's growing wind field
are expected to reach the Lesser Antilles on Sunday, and then
spread westward to portions of the Greater Antilles, the Bahamas,
and Bermuda on Monday and Tuesday. These swells could cause
life-threatening rip currents and high surf conditions. Large
swells are also likely to spread to the east coast of the United
States by midweek.


FORECAST POSITIONS AND MAX WINDS

INIT 04/0300Z 15.5N 43.3W 100 KT 115 MPH
12H 04/1200Z 16.2N 45.3W 110 KT 125 MPH
24H 05/0000Z 17.4N 47.6W 115 KT 130 MPH
36H 05/1200Z 18.7N 49.7W 120 KT 140 MPH
48H 06/0000Z 20.0N 51.7W 120 KT 140 MPH
60H 06/1200Z 21.2N 53.6W 120 KT 140 MPH
72H 07/0000Z 22.4N 55.3W 115 KT 130 MPH
96H 08/0000Z 25.4N 58.5W 115 KT 130 MPH
120H 09/0000Z 29.5N 61.5W 105 KT 120 MPH

$$
Forecaster Berg

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 15
NWS National Hurricane Center Miami FL AL122021
500 AM AST Sat Sep 04 2021

...LARRY FORECAST TO REMAIN A MAJOR HURRICANE FOR SEVERAL DAYS...
...DANGEROUS SURF AND RIP CURRENTS EXPECTED TO DEVELOP ALONG MANY
WESTERN ATLANTIC SHORES NEXT WEEK...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...16.3N 44.6W
ABOUT 1140 MI...1830 KM E OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...965 MB...28.50 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Hurricane Larry was located
near latitude 16.3 North, longitude 44.6 West. Larry is moving
toward the west-northwest near 16 mph (26 km/h). A slightly slower
west-northwest to northwest motion is expected during the next few
days.

Maximum sustained winds are near 115 mph (185 km/h) with higher
gusts. Larry is a category 3 hurricane on the Saffir-Simpson
Hurricane Wind Scale. Strengthening is forecast over the next day
or two, and Larry is expected to remain at major hurricane strength
through the early part of next week.

Hurricane-force winds extend outward up to 35 miles (55 km) from the
center and tropical-storm-force winds extend outward up to 150 miles
(240 km).

The estimated minimum central pressure is 965 mb (28.50 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Larry are expected to reach the Lesser
Antilles on Sunday, and will continue to spread westward to
portions of the Greater Antilles, the Bahamas, and Bermuda Monday
and Tuesday. Significant swells will likely reach the eastern
United States coastline after Labor Day. These swells are likely to
cause life-threatening surf and rip current conditions. Please
consult products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Cangialosi


Hurricane Larry Discussion Number 15
NWS National Hurricane Center Miami FL AL122021
500 AM AST Sat Sep 04 2021

Larry's strengthening trend appears to have paused for the moment.
The hurricane has generally changed little during the past several
hours with the inner core still fairly symmetric, though cloud tops
are coldest to the south of the ragged eye. The outer bands are also
quite distinct, especially to the south of the center. The latest
Dvorak estimates still range from 90 to 110 kt, and based on that
data, the initial intensity is held at 100 kt.

The hurricane is moving west-northwestward, or 295 degrees, at 14
kt. Larry is expected to continue moving west-northwestward to
northwestward during the next few days as it remains steered by a
subtropical ridge to its northeast. By the middle of next week, a
turn to the north-northwest is forecast when the hurricane reaches
the western periphery of the ridge. The models are in fairly good
agreement, and the NHC track forecast lies fairly close to the HCCA
and TVCA consensus aids. Based on this forecast, Larry is expected
to be moving across the central Atlantic during the next several
days and approach Bermuda by the end of the forecast period.

Larry is expected to remain in generally favorable conditions for
strengthening during the next couple of days, with SSTs increasing
along the storm's track and vertical wind shear remaining fairly
low. The models suggest that there could be an increase in shear
early next week, and that combined with slightly drier and more
stable air should end the strengthening trend and likely cause some
weakening. It should be noted that eyewall replacement cycles are a
possibility at some point during the forecast period, and these can
cause intensity fluctuations that are difficult to predict.
Regardless of the details, Larry is expected to remain a major
hurricane during the next several days. The NHC intensity forecast
is just an update of the previous one and lies near the high end of
the model guidance.

Significant ocean swells generated by Larry's growing wind field
are expected to reach the Lesser Antilles on Sunday, and then
spread westward to portions of the Greater Antilles, the Bahamas,
and Bermuda on Monday and Tuesday. These swells could cause
life-threatening rip currents and high surf conditions. Large
swells are also likely to spread to the east coast of the United
States by midweek.


FORECAST POSITIONS AND MAX WINDS

INIT 04/0900Z 16.3N 44.6W 100 KT 115 MPH
12H 04/1800Z 17.2N 46.5W 110 KT 125 MPH
24H 05/0600Z 18.4N 48.6W 115 KT 130 MPH
36H 05/1800Z 19.7N 50.7W 120 KT 140 MPH
48H 06/0600Z 21.0N 52.6W 120 KT 140 MPH
60H 06/1800Z 22.0N 54.3W 115 KT 130 MPH
72H 07/0600Z 23.3N 56.0W 115 KT 130 MPH
96H 08/0600Z 26.1N 59.0W 110 KT 125 MPH
120H 09/0600Z 30.6N 62.0W 105 KT 120 MPH

$$
Forecaster Cangialosi

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 16
NWS National Hurricane Center Miami FL AL122021
1100 AM AST Sat Sep 04 2021

...LARRY LARGER AND A LITTLE STRONGER...
...DANGEROUS SURF AND RIP CURRENTS EXPECTED TO DEVELOP ALONG MANY
WESTERN ATLANTIC SHORES NEXT WEEK...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...16.8N 45.8W
ABOUT 1055 MI...1700 KM E OF THE LEEWARD ISLANDS
ABOUT 1600 MI...2570 KM SE OF BERMUDA
MAXIMUM SUSTAINED WINDS...125 MPH...205 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...958 MB...28.29 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Hurricane Larry was located
near latitude 16.8 North, longitude 45.8 West. Larry is moving
toward the west-northwest near 15 mph (24 km/h). A gradually slower
west-northwest to northwest motion is expected during the next few
days.

Maximum sustained winds have increased to near 125 mph (205 km/h)
with higher gusts. Larry is a category 3 hurricane on the
Saffir-Simpson Hurricane Wind Scale and additional strengthening is
forecast over the next day or two. Larry is expected to remain at
major hurricane strength through the early part of next week.

Hurricane-force winds extend outward up to 45 miles (75 km) from the
center and tropical-storm-force winds extend outward up to 160 miles
(260 km).

The estimated minimum central pressure is 958 mb (28.29 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Larry are expected to reach the Lesser
Antilles on Sunday, and will continue to spread westward to
portions of the Greater Antilles, the Bahamas, and Bermuda Monday
and Tuesday. Significant swells will likely reach the eastern
United States coastline after Labor Day. These swells are likely to
cause life-threatening surf and rip current conditions. Please
consult products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Papin


Hurricane Larry Discussion Number 16
NWS National Hurricane Center Miami FL AL122021
1100 AM AST Sat Sep 04 2021

Overnight and this morning, Larry appears to have gone through a
rather quick eyewall replacement cycle (ERC). The most recent 1000
UTC GMI microwave pass suggests that Larry now has a much larger eye
and surrounding eyewall, with less evidence of concentric bands as
noted yesterday. On geostationary satellite the larger eye is also
becoming apparent on visible and infrared channels, though some left
over inner eyewall debris remains. Consistent with the larger eye,
an ASCAT-B pass received at 1226 UTC indicated that the 34-, 50-,
and 64-kt wind radii have expanded with Larry this morning. While
the most recent SAB and TAFB subjective Dvorak intensity estimates
have remain at 90 kt and 100 kt respectively, the
objective estimates are higher, with an earlier UW-CIMSS SATCON
estimate up to 112 kt, though it has recently been adjusted lower.
With the eye beginning to clear out on the most recent satellite
images, I am favoring the higher objective estimates, bringing Larry
up to 110 kt for this advisory.

Larry's track has remained fairly steady toward the west-northwest,
but
just a touch slower and more poleward with the latest estimated
motion at 300/13 kt. This west-northwest motion is expected to
continue for the next several days with only a very gradual
poleward bend as Larry remains positioned to the south of an
expansive mid-level ridge extending westward ahead of Larry's
expected path. As has been the case the last several days, the
track guidance is in excellent agreement over the next 36-48 hours
with more spread becoming apparent thereafter. As discussed
yesterday, the increase in spread in the latter portion of the
forecast appears to be related to how much mid-level ridging stays
north of Larry. The ECMWF and its ensembles maintain more ridging
that results in a slower and more westward track, while the GFS and
its ensembles place more ridging east of Larry that results in a
faster more eastward track. The UKMET favors a solution closer to
the ECMWF while the Canadian favors a solution closer to the GFS.
For now, the latest NHC track has elected to remain close to the
HFIP corrected consensus approach (HCCA) which slightly favors the
ECMWF solution over the GFS. This latest track forecast is quite
similar to the previous one, but just a touch slower. Based on this
forecast, Larry will continue moving across the central Atlantic in
the coming days, and be approaching the latitude of Bermuda by the
end of the forecast period.

Conditions continue to remain favorable for additional
intensification over the next few days, with vertical wind shear
remaining under 10 kts, sea-surface temperatures gradually
increasing, and mid-level relatively humidity staying fairly moist.
However, by 48 hours, Larry will be impinging on the eastern edge of
a large upper-level mid-oceanic trough, which could result in an
increase in westerly vertical wind shear over the hurricane.
However, the models handle Larry's interaction with this synoptic
feature differently. The GFS suggests this upper-level trough will
fracture to the west fairly quickly, keeping a more favorable
upper-level pattern over Larry, while the ECMWF has a stronger
trough that takes longer to give way to Larry's upper-level outflow,
providing more westerly shear over the hurricane. Additional eyewall
replacement cycles are also possible in the coming days, which could
result in additional intensity fluctuations that are challenging to
predict ahead of time. For now, the latest NHC intensity forecast
keeps Larry intensifying over the next 24-36 hours, with only a very
gradual decay thereafter due to the somewhat less favorable
dynamical environment. The latest intensity forecast remains on the
high end of the guidance, noting that there still remain higher
outliers making Larry stronger than the 125 kt peak intensity
(HAFS-B, COAMPS-TC). Regardless of the details, Larry is expected to
remain a large major hurricane through the forecast period.

Significant ocean swells generated by Larry's growing wind field are
expected to reach the Lesser Antilles tomorrow, and then spread
westward to portions of the Greater Antilles, the Bahamas, and
Bermuda on Monday and Tuesday. These swells could cause
life-threatening rip currents and high surf conditions. Large
swells are also likely to spread to the east coast of the United
States by midweek.


FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 16.8N 45.8W 110 KT 125 MPH
12H 05/0000Z 17.7N 47.5W 115 KT 130 MPH
24H 05/1200Z 19.1N 49.6W 120 KT 140 MPH
36H 06/0000Z 20.3N 51.5W 125 KT 145 MPH
48H 06/1200Z 21.5N 53.2W 120 KT 140 MPH
60H 07/0000Z 22.6N 54.8W 120 KT 140 MPH
72H 07/1200Z 23.8N 56.4W 115 KT 130 MPH
96H 08/1200Z 27.0N 59.4W 110 KT 125 MPH
120H 09/1200Z 31.6N 62.0W 100 KT 115 MPH

$$
Forecaster Papin

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 17
NWS National Hurricane Center Miami FL AL122021
500 PM AST Sat Sep 04 2021

...LARRY IS A LARGE AND POWERFUL HURRICANE...
...DANGEROUS SURF AND RIP CURRENTS EXPECTED TO DEVELOP ALONG MANY
WESTERN ATLANTIC SHORES NEXT WEEK...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...17.4N 47.1W
ABOUT 970 MI...1560 KM E OF THE LEEWARD ISLANDS
ABOUT 1510 MI...2425 KM SE OF BERMUDA
MAXIMUM SUSTAINED WINDS...125 MPH...205 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...958 MB...28.29 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Hurricane Larry was located
near latitude 17.4 North, longitude 47.1 West. Larry is moving
toward the west-northwest near 14 mph (22 km/h). A somewhat slower
west-northwest to northwest motion is expected during the next few
days.

Maximum sustained winds are near 125 mph (205 km/h) with higher
gusts. Larry is a category 3 hurricane on the Saffir-Simpson
Hurricane Wind Scale. Some additional strengthening is forecast
over the next day or so, followed by some intensity fluctuations.
However, Larry is expected to remain at major hurricane strength
through the early part of next week.

Hurricane-force winds extend outward up to 45 miles (75 km) from the
center and tropical-storm-force winds extend outward up to 160 miles
(260 km).

The estimated minimum central pressure is 958 mb (28.29 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Larry are expected to reach the Lesser
Antilles on Sunday, and will continue to spread westward to
portions of the Greater Antilles, the Bahamas, and Bermuda Monday
and Tuesday. Significant swells will likely reach the eastern
United States coastline after Labor Day. These swells are likely to
cause life-threatening surf and rip current conditions. Please
consult products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Papin




Hurricane Larry Discussion Number 17
NWS National Hurricane Center Miami FL AL122021
500 PM AST Sat Sep 04 2021

Larry remains a formidable hurricane this afternoon. Both visible
and infrared satellite bands show the hurricane has a well-defined
and warm eye (greater than 10 C) surrounded by a cold ring of
eyewall convection (-60 to -70 C). An AMSR2 microwave pass received
at 1630 UTC showed the well-defined eye of Larry, though the 89 GHz
channel hinted that the eyewall was weaker on its eastern side.
Taking a look at the high-density atmospheric motion vectors (AMVs),
available thanks to a GOES-16 1-minute updating domain over Larry,
there is some restriction of Larry's outflow to the southwest.
Flight-level wind data from the NASA-DC8 aircraft conducting a
research mission around Larry also showed some light southwesterly
flow between 10-20 kt just a few degrees to the south and west of
the storm center. These data suggest that the upper-level wind
environment is not as pristine as earlier suggested by SHIPS
guidance, with the southwesterly flow likely restricting Larry's
outflow in that quadrant. The SAB/TAFB subjective Dvorak intensity
estimates are unchanged from this morning, and the latest UW-CIMSS
ADT and SATCON estimates have also plateaued in the 105-110 kt
range. Therefore, Larry was maintained as a 110 kt hurricane this
advisory.

Larry remains on a west-northwest track this afternoon, but a bit
slower at 300/12 kt. There has been little change to the track
philosophy over the next several days, as the guidance is in good
agreement that Larry will maintain a continued west-northwest
heading while gradually slowing down as it rounds the southern
periphery of a large mid-level ridge. However, there has been a
notable eastward shift in the track guidance in the short-term. The
latest ECMWF run, which had previously been on the southwest side of
the track guidance envelope, is now very similar or even a tad east
of the latest GFS run. This shift has also resulted in an eastward
adjustment in the consensus aids this afternoon. The latest NHC
track forecast was adjusted a bit to the right early on, but not as
far right as the HCCA and TVCA aids. After 72 hours, the track
guidance actually converges very close to the previous track
forecast, and few changes were needed after this time period. Based
on this forecast, Larry will continue moving across the central
Atlantic in the coming days, and be approaching Bermuda from the
southeast in the day 4 to 5 forecast period.

The existence of some light upper-level southwesterly flow ahead of
Larry today was bit of a surprise, since the SHIPS guidance from the
last few days suggested the shear-vector would be out of the east
and weak. Indeed, the latest ECMWF-SHIPS guidance now shows moderate
southwesterly vertical wind shear beginning earlier, and peaking
between 20-25 knots in 36 to 48 hours. While the GFS-SHIPS shear
remains much lower, given what I'm seeing from the latest
upper-level flow in front of Larry, the ECMWF seems closer to
correct. For this reason, the latest NHC intensity guidance now
shows a bit of weakening after 24 hours, when the shear magnitude is
expected to peak as the hurricane interacts with a large tropical
upper-tropospheric trough (TUTT) located to its northwest. However,
Larry has a large and vertically-deep circulation, and ultimately it
will win the battle against the more vertically shallow TUTT, which
is forecast to cut off and move away from the hurricane's expansive
upper-level outflow. By 60 hours, this change in the synoptic
pattern should once again reduce the vertical wind shear over Larry,
and it will have a chance to achieve a secondary peak between the
60-84 hour time-frame. However, eyewall replacement cycles could
also occur at any time over the next 2-5 days, providing additional
intensity fluctuations that make this a challenging intensity
forecast. The latest NHC intensity forecast is lower than the
previous one, but still remains higher than the latest HCCA
consensus aid. Regardless of the details, Larry is expected to
remain a large major hurricane over the next 3-4 days.

Key Messages:

1. Large swells generated by Larry are expected to first reach the
Lesser Antilles on Sunday and will spread to portions of the Greater
Antilles, the Bahamas, and Bermuda Monday and Tuesday. Significant
swells will likely reach the east coast of the United States and
Atlantic Canada around midweek. These swells will likely cause
life-threatening surf and rip current conditions, and beachgoers
and other interests along these coasts are urged to follow the
advice of lifeguards and local officials through the upcoming week.

2. Larry is forecast to approach Bermuda during the next several
days, possibly as a major hurricane, bringing a risk of strong
winds, heavy rainfall, and coastal flooding to the island by the
middle of next week. While it is too soon to determine the
magnitude of these hazards and potential impacts on Bermuda,
interests there should monitor changes to the forecast during the
next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 04/2100Z 17.4N 47.1W 110 KT 125 MPH
12H 05/0600Z 18.4N 48.6W 115 KT 130 MPH
24H 05/1800Z 19.8N 50.6W 120 KT 140 MPH
36H 06/0600Z 21.0N 52.3W 115 KT 130 MPH
48H 06/1800Z 22.2N 54.0W 110 KT 125 MPH
60H 07/0600Z 23.4N 55.6W 110 KT 125 MPH
72H 07/1800Z 24.7N 57.0W 115 KT 130 MPH
96H 08/1800Z 28.3N 59.9W 110 KT 125 MPH
120H 09/1800Z 33.4N 61.9W 95 KT 110 MPH

$$
Forecaster Papin

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 18
NWS National Hurricane Center Miami FL AL122021
1100 PM AST Sat Sep 04 2021

...DANGEROUS SURF AND RIP CURRENTS EXPECTED ALONG MANY WESTERN
ATLANTIC SHORES NEXT WEEK DUE TO LARRY'S LARGE SWELLS...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...18.0N 48.0W
ABOUT 910 MI...1465 KM E OF THE LEEWARD ISLANDS
ABOUT 1440 MI...2315 KM SE OF BERMUDA
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...958 MB...28.29 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the large eye of Hurricane Larry was
located near latitude 18.0 North, longitude 48.0 West. Larry is
moving toward the west-northwest near 14 mph (22 km/h). A turn
toward the northwest is expected overnight, with Larry maintaining
that heading at gradually slower speeds through Tuesday.

Maximum sustained winds are near 120 mph (195 km/h) with higher
gusts. Larry is a category 3 hurricane on the Saffir-Simpson
Hurricane Wind Scale. Little change in strength is forecast during
the next few days, although fluctuations in intensity will be
possible. Larry is expected to remain a major hurricane through
the middle of next week.

Hurricane-force winds extend outward up to 45 miles (75 km) from the
center and tropical-storm-force winds extend outward up to 160 miles
(260 km).

The estimated minimum central pressure is 958 mb (28.29 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Larry are expected to reach the Lesser
Antilles on Sunday, and will spread westward to portions of the
Greater Antilles, the Bahamas, and Bermuda Monday and Tuesday.
Significant swells will likely reach the east coast of the United
States and Atlantic Canada around midweek. These swells are
likely to cause life-threatening surf and rip current conditions.
Please consult products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 500 AM AST.

$$
Forecaster Berg




Hurricane Larry Discussion Number 18
NWS National Hurricane Center Miami FL AL122021
1100 PM AST Sat Sep 04 2021

Larry has developed a large eye this evening that is 40-45 n mi in
diameter, and the surrounding cloud tops have warmed somewhat.
There have been no microwave passes over the hurricane for quite
some time to assess its structure, but conventional satellite images
suggest that Larry has taken on some annular characteristics (and
the objective screening algorithm tagged it as marginally annular).
Dvorak CI numbers and objective estimates are all between 100-102
kt, so Larry's initial intensity is lowered slightly to 105 kt.

Larry's motion remains west-northwestward (300 degrees) at 12 kt.
The hurricane is expected to turn northwestward tonight or early
Sunday around the southwestern periphery of a mid-level high
centered over the central Atlantic, and then maintain that heading
with some decrease in forward speed through day 4. By day 5, Larry
should turn northward and accelerate between the high and an
approaching deep-layer trough over the eastern United States. The
updated NHC track forecast is largely unchanged from the previous
advisory and is of high confidence since there is lower-than-normal
spread among the track models. Larry is forecast to make its
closest approach to Bermuda in 4 to 5 days while it recurves around
the ridge, but despite the high-confidence forecast, there is still
uncertainty on how close that approach will be since several GEFS
and ECMWF ensemble members bring Larry's center very close to or
over the island. Even with a track east of the island, Larry will
be large enough to possibly cause some impacts on Bermuda.

Water vapor imagery shows some restriction to the outflow in the
southwestern quadrant, which could be indicative of some shear.
There continues to be some discrepancy among the models on how much
shear the hurricane will contend with as it approaches a
mid-/upper-level trough located north of the Leeward Islands. The
GFS keeps the shear over Larry fairly low since it's farther from
the trough, while the ECMWF increases the shear to moderate or
strong levels during the next 48 hours. If Larry reaches the area
of stronger shear, its intensity would obviously be adversely
affected. In terms of structure, significant re-intensification is
now less likely since Larry has such a large eye and an expanding
wind field. On the positive side, the hurricane will be moving
over gradually warmer waters for the next 3 days or so. Given
these conflicting factors, the updated NHC intensity forecast allows
for some slight restrengthening in the short term but then keeps
Larry's intensity steady for the next 3 days. Many of the intensity
models are even lower than what's shown in this forecast, so
additional adjustments may be required in future advisories.


Key Messages:

1. Large swells generated by Larry are expected to first reach the
Lesser Antilles on Sunday and will spread to portions of the Greater
Antilles, the Bahamas, and Bermuda Monday and Tuesday. Significant
swells will likely reach the east coast of the United States and
Atlantic Canada around midweek. These swells will likely cause
life-threatening surf and rip current conditions, and beachgoers
and other interests along these coasts are urged to follow the
advice of lifeguards and local officials through the upcoming week.

2. Larry is forecast to approach Bermuda during the next several
days, possibly as a major hurricane, bringing a risk of strong
winds, heavy rainfall, and coastal flooding to the island by the
middle of next week. While it is too soon to determine the
magnitude of these hazards and potential impacts on Bermuda,
interests there should monitor changes to the forecast during the
next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0300Z 18.0N 48.0W 105 KT 120 MPH
12H 05/1200Z 19.1N 49.5W 110 KT 125 MPH
24H 06/0000Z 20.5N 51.3W 110 KT 125 MPH
36H 06/1200Z 21.7N 53.0W 110 KT 125 MPH
48H 07/0000Z 23.0N 54.5W 110 KT 125 MPH
60H 07/1200Z 24.2N 56.0W 110 KT 125 MPH
72H 08/0000Z 25.8N 57.5W 105 KT 120 MPH
96H 09/0000Z 29.4N 60.5W 100 KT 115 MPH
120H 10/0000Z 35.1N 61.4W 90 KT 105 MPH

$$
Forecaster Berg

[cycloneye]

BULLETIN
Hurricane Larry Advisory Number 19
NWS National Hurricane Center Miami FL AL122021
500 AM AST Sun Sep 05 2021

...DANGEROUS SURF AND RIP CURRENTS EXPECTED ALONG MANY WESTERN
ATLANTIC SHORES LATER THIS WEEK DUE TO LARGE SWELLS FROM LARRY...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...18.8N 49.0W
ABOUT 925 MI...1485 KM E OF THE NORTHERN LEEWARD ISLANDS
ABOUT 1350 MI...2175 KM SE OF BERMUDA
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...958 MB...28.29 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Hurricane Larry was located
near latitude 18.8 North, longitude 49.0 West. Larry is moving
toward the northwest near 14 mph (22 km/h). A northwestward motion
with a slight decrease in forward speed is expected during the next
few days.

Maximum sustained winds are near 120 mph (195 km/h) with higher
gusts. Larry is a category 3 hurricane on the Saffir-Simpson
Hurricane Wind Scale. Little change in strength is forecast during
the next few days, although fluctuations in intensity will be
possible. Larry is expected to remain a major hurricane through the
middle of this week.

Hurricane-force winds extend outward up to 45 miles (75 km) from the
center and tropical-storm-force winds extend outward up to 160 miles
(260 km).

The estimated minimum central pressure is 958 mb (28.29 inches). A
drifting buoy near the center of Larry recently measured a pressure
of 962.9 mb (28.43 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Larry are expected to reach the Lesser
Antilles today, and will spread westward to portions of the Greater
Antilles, the Bahamas, and Bermuda on Monday and Tuesday.
Significant swells will likely reach the east coast of the United
States and Atlantic Canada by midweek. These swells are likely to
cause life-threatening surf and rip current conditions. Please
consult products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Reinhart




Hurricane Larry Discussion Number 19
NWS National Hurricane Center Miami FL AL122021
500 AM AST Sun Sep 05 2021

Larry remains a powerful hurricane this morning. The system has a
warm, well-defined eye with a large diameter of around 40 n mi.
Larry's central dense overcast has become more symmetric overnight,
although the upper-level outflow is still somewhat restricted on the
southwestern side of the hurricane. This is likely an indication of
some vertical wind shear impinging on the cyclone. However, recent
AMSR2 microwave data indicate that the vortex is still well-aligned
vertically, with a pronounced eyewall that slopes outward with
height. The initial intensity is held at 105 kt for this advisory
based on consensus T5.5/102 kt Dvorak classifications from TAFB and
SAB, and a recent UW-CIMSS ADT estimate of 105 kt.

The initial motion of Larry is northwestward, or 305/12 kt. Larry is
expected to continue moving northwestward for the next several days
around the southwestern periphery of a mid-level ridge over the
central Atlantic. By Thursday, the cyclone is forecast to accelerate
northward ahead of a deep-layer trough that will move off the east
coast of the United States later this week. The latest track
guidance is very tightly clustered, and the official NHC forecast is
similar to the previous one and lies near the multi-model consensus
aids. Confidence remains high in Larry's track forecast given the
excellent model agreement. The hurricane is still expected to make
its closest approach to Bermuda at days 4 and 5, but it remains too
early to pinpoint how close it will come to the island. Even if the
center passes east of Bermuda as forecast, it could still be large
enough to produce some impacts on the island.

Over the next few days, some fluctuations in Larry's intensity are
possible. The oceanic heat content along the forecast track is
certainly sufficient for some intensification. However, vertical
wind shear associated with an upper-level trough/low to the west of
Larry may inhibit strengthening at times during the next couple of
days, especially if the stronger shear values in the ECMWF-based
SHIPS guidance are realized. Given Larry's large eye size, it does
not appear as if the cyclone is poised to significantly intensify.
The official NHC intensity forecast shows slight strengthening in
the near-term, but then levels off the intensity through 48 h. The
NHC forecast keeps Larry at major hurricane intensity through day 4,
as the environment appears favorable enough between 48-96 h for
Larry to maintain its organization, even as the cyclone gains
latitude. Overall, this forecast lies on the high end of the
intensity guidance, above the HFIP corrected consensus approach
(HCCA) and the other multi-model consensus aids.


Key Messages:

1. Large swells generated by Larry are expected to reach the Lesser
Antilles today and will spread to portions of the Greater Antilles,
the Bahamas, and Bermuda on Monday and Tuesday. Significant swells
will likely reach the east coast of the United States and Atlantic
Canada by midweek. These swells will likely cause life-threatening
surf and rip current conditions, and beachgoers and other interests
along these coasts are urged to follow the advice of lifeguards and
local officials this week.

2. Larry is forecast to approach Bermuda during the next several
days, possibly as a major hurricane, bringing a risk of strong
winds, heavy rainfall, and coastal flooding to the island by the
middle of this week. While it is too soon to determine the
magnitude of these hazards and potential impacts on Bermuda,
interests there should closely monitor the latest forecast updates
during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 18.8N 49.0W 105 KT 120 MPH
12H 05/1800Z 19.9N 50.4W 110 KT 125 MPH
24H 06/0600Z 21.2N 52.1W 110 KT 125 MPH
36H 06/1800Z 22.4N 53.6W 110 KT 125 MPH
48H 07/0600Z 23.6N 55.0W 110 KT 125 MPH
60H 07/1800Z 25.0N 56.4W 105 KT 120 MPH
72H 08/0600Z 26.5N 57.8W 105 KT 120 MPH
96H 09/0600Z 30.4N 60.8W 100 KT 115 MPH
120H 10/0600Z 36.5N 61.0W 90 KT 105 MPH

$$
Forecaster Reinhart