ATL: HENRI - Advisories

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ATL: HENRI - Advisories

#1 Postby cycloneye » Sun Aug 15, 2021 10:02 pm

BULLETIN
Tropical Depression Eight Advisory Number 1
NWS National Hurricane Center Miami FL AL082021
1100 PM AST Sun Aug 15 2021

...NEW TROPICAL DEPRESSION FORMS NORTHEAST OF BERMUDA...
...TROPICAL STORM WATCH ISSUED FOR BERMUDA AND NEARBY WATERS...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...33.2N 62.7W
ABOUT 135 MI...220 KM ENE OF BERMUDA
MAXIMUM SUSTAINED WINDS...30 MPH...45 KM/H
PRESENT MOVEMENT...S OR 175 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1014 MB...29.95 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The Bermuda Weather Service has issued a Tropical Storm Watch for
Bermuda.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Bermuda

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Tropical Depression Eight
was located near latitude 33.2 North, longitude 62.7 West. The
depression is moving toward the south near 7 mph (11 km/h). A slow
clockwise turn toward the west is anticipated during the next
couple of days, followed by a continued westward motion on
Wednesday. On the forecast track, the center of the depression will
move east and south of Bermuda during the next few days.

Maximum sustained winds are near 30 mph (45 km/h) with higher gusts.
Slow strengthening is forecast and the system is forecast to become
a tropical storm on Monday.

The estimated minimum central pressure is 1014 mb (29.95 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are possible across Bermuda and
the nearby waters on Tuesday, particularly to the south of the
island.


NEXT ADVISORY
-------------
Next intermediate advisory at 200 AM AST.
Next complete advisory at 500 AM AST.

$$
Forecaster Zelinsky



Tropical Depression Eight Discussion Number 1
NWS National Hurricane Center Miami FL AL082021
1100 PM AST Sun Aug 15 2021

A small well-defined low pressure system located just
east-northeast of Bermuda has produced persistent deep convection
since this morning. Radar imagery from Bermuda along with
geostationary and polar orbiting microwave satellite data show that
the convection is sufficiently well organized to meet the
definition for a tropical cyclone. Therefore advisories have been
started on Tropical Depression Eight. The initial intensity is set
at 25 kt, based on believable winds near that value in a pair of
recent ASCAT overpasses. Dvorak estimates from TAFB and SAB were a
little higher, so this estimate could be slightly conservative.

Confidence in the forecast is reasonably high for the next 48 to
72 h. The depression should make a slow clockwise turn around
Bermuda, steered by a mid-level ridge currently centered off the
coast of the Carolinas. Warm SSTs should provide ample fuel to
support at least slight strengthening during this period, despite
expected northerly shear, and this is shown by all of the intensity
guidance. The NHC forecast is very near the multi-model consensus
for both track and intensity through that period.

Beyond 72 h, the track and intensity models diverge quickly. The
HWRF and COAMPS-TC models rapidly intensify the system to major
hurricane strength. A stronger, deeper vortex would likely be
steered generally westward through the end of the forecast period,
influenced by a deeper-layer steering flow. However, the global
models have a much weaker, shallower system which turns northward,
and then possibly accelerates northeastward by day 5. As a result,
the spread in the track guidance is nearly 800 n mi by day 5, with
the GFS and HWRF taking the extreme positions to the northeast and
southwest, respectively. The official track forecast takes a middle
approach, and is between the various consensus aids at days 4 and
5. The NHC intensity forecast is slightly more conservative, and is
below the consensus at the end of the period. Significant changes
to the forecast may be required in subsequent advisory packages.


FORECAST POSITIONS AND MAX WINDS

INIT 16/0300Z 33.2N 62.7W 25 KT 30 MPH
12H 16/1200Z 32.4N 62.8W 30 KT 35 MPH
24H 17/0000Z 31.5N 63.3W 35 KT 40 MPH
36H 17/1200Z 31.1N 64.0W 40 KT 45 MPH
48H 18/0000Z 31.0N 64.9W 45 KT 50 MPH
60H 18/1200Z 31.0N 66.1W 50 KT 60 MPH
72H 19/0000Z 31.2N 67.4W 55 KT 65 MPH
96H 20/0000Z 32.0N 68.5W 55 KT 65 MPH
120H 21/0000Z 33.5N 68.0W 55 KT 65 MPH

$$
Forecaster Zelinsky
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Re: ATL: EIGHT - Advisories

#2 Postby cycloneye » Mon Aug 16, 2021 3:54 am

Tropical Depression Eight Intermediate Advisory Number 1A
NWS National Hurricane Center Miami FL AL082021
200 AM AST Mon Aug 16 2021

...TROPICAL DEPRESSION STRENGTHENS TO THE EAST OF BERMUDA...


SUMMARY OF 200 AM AST...0600 UTC...INFORMATION
----------------------------------------------
LOCATION...32.6N 62.8W
ABOUT 135 MI...220 KM ENE OF BERMUDA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...S OR 185 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1012 MB...29.88 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Bermuda

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 200 AM AST (0600 UTC), the center of Tropical Depression Eight
was located near latitude 32.6 North, longitude 62.8 West. The
depression is moving toward the south near 8 mph (13 km/h). A slow
clockwise turn toward the west is anticipated during the next couple
of days, followed by a continued westward motion on Wednesday. On
the forecast track, the center of the depression will move east and
south of Bermuda during the next few days.

Maximum sustained winds have increased to near 35 mph (55 km/h)
with higher gusts. Slow strengthening is forecast and the system is
forecast to become a tropical storm later today.

The estimated minimum central pressure is 1012 mb (29.88 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are possible across Bermuda and
the nearby waters on Tuesday, particularly to the south of the
island.


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

$$
Forecaster Stewart



Tropical Depression Eight Advisory Number 2
NWS National Hurricane Center Miami FL AL082021
500 AM AST Mon Aug 16 2021

...TROPICAL DEPRESSION PASSING TO THE EAST-SOUTHEAST OF BERMUDA...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...32.4N 62.9W
ABOUT 110 MI...180 KM E OF BERMUDA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...SSW OR 195 DEGREES AT 5 MPH...7 KM/H
MINIMUM CENTRAL PRESSURE...1012 MB...29.89 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Bermuda

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Tropical Depression Eight
was located near latitude 32.4 North, longitude 62.9 West. The
depression is moving toward the south-southwest near 5 mph (7 km/h)
and this motion is expected to continue this morning. A slow
clockwise turn toward the southwest and west is anticipated during
the next couple of days, followed by a continued westward motion on
Wednesday. On the forecast track, the center of the depression will
pass to the southeast and south of Bermuda during the next few days.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Slow strengthening is forecast and the system is forecast to become
a tropical storm later today.

The estimated minimum central pressure is 1012 mb (29.89 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are possible across Bermuda and
the nearby waters on Tuesday, particularly to the south of the
island.


NEXT ADVISORY
-------------
Next intermediate advisory at 800 AM AST.
Next complete advisory at 1100 AM AST.

$$
Forecaster Stewart



Tropical Depression Eight Discussion Number 2
NWS National Hurricane Center Miami FL AL082021
500 AM AST Mon Aug 16 2021

Satellite imagery and radar data from Bermuda indicate that the
tropical depression located about 100 nmi east of Bermuda has been
moving southward and also remains a sheared tropical cyclone -- the
ongoing saga of the Atlantic basin thus far this hurricane season.
Convection has increased and developed closer to the center and a
late-arriving ASCAT-C overpass indicated surface winds of 26-27 kt
to the south of the well-defined circulation center. Based on those
data, the slightly improved convective structure noted in both
satellite and radar data, and satellite classifications of T2.0/30
kt, the initial intensity has been increased to 30 kt.

The initial motion estimate is 195/04 kt. The small cyclone is
starting to make the clockwise turn toward the south-southwest and
eventually southwest that the global and regional models have been
advertising the past couple of days. The latest NHC model guidance
now shows less of a turn to the northwest after 72 hours, with the
exception of the GFS, GFS-ensemble, and HMON models, which continue
to take the cyclone northward and northeastward around Bermuda on
day 4 and 5. The latest NHC track forecast is similar to the
previous advisory track through 60 hours, and then widens the track
slightly thereafter, but still shows a complete clockwise turn. This
track scenario is to the right of the consensus models at all
forecast periods, and is of low confidence on days 4 and 5.

The vertical wind shear is forecast to remain at or below 10 kt for
the next 36 hours or so, and that is most likely the time when the
cyclone will strengthen. Thereafter, an increase in the shear to 20
kt or more is expected to cap the intensification process. The HWRF
model turn the cyclone into a major hurricane by 72 hours, but this
scenario is considered to be an extreme outlier given the amount of
shear forecast to affect the system on days 3-5. So far this season,
the HWRF model has been very shear resistant and has had a high
intensity bias. The official intensity forecast closely follows a
blend of the IVCN and HCCA consensus models through 60 hours, and
then is below those models due to the high-bias contribution of the
HWRF model.


FORECAST POSITIONS AND MAX WINDS

INIT 16/0900Z 32.4N 62.9W 30 KT 35 MPH
12H 16/1800Z 31.6N 63.1W 35 KT 40 MPH
24H 17/0600Z 31.0N 63.7W 40 KT 45 MPH
36H 17/1800Z 30.7N 64.5W 45 KT 50 MPH
48H 18/0600Z 30.7N 65.5W 50 KT 60 MPH
60H 18/1800Z 30.8N 66.7W 55 KT 65 MPH
72H 19/0600Z 31.1N 68.0W 55 KT 65 MPH
96H 20/0600Z 32.0N 69.0W 55 KT 65 MPH
120H 21/0600Z 34.0N 68.5W 55 KT 65 MPH

$$
Forecaster Stewart
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Re: ATL: EIGHT - Advisories

#3 Postby AlphaToOmega » Mon Aug 16, 2021 6:37 am

584
WTNT33 KNHC 161132
TCPAT3

BULLETIN
Tropical Depression Eight Intermediate Advisory Number 2A
NWS National Hurricane Center Miami FL AL082021
800 AM AST Mon Aug 16 2021

...TROPICAL DEPRESSION MOVING SOUTHWARD...


SUMMARY OF 800 AM AST...1200 UTC...INFORMATION
----------------------------------------------
LOCATION...31.7N 62.8W
ABOUT 120 MI...190 KM ESE OF BERMUDA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...S OR 185 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1012 MB...29.89 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Bermuda

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 800 AM AST (1200 UTC), the center of Tropical Depression Eight
was located near latitude 31.7 North, longitude 62.8 West. The
depression is moving toward the south near 9 mph (15 km/h), and
this motion is expected to continue this morning. A slow
clockwise turn toward the southwest and west is anticipated during
the next couple of days, followed by a continued westward motion on
Wednesday. On the forecast track, the center of the depression will
pass to the southeast and south of Bermuda during the next few days.

Maximum sustained winds are near 35 mph (55 km/h) with higher
gusts. Slow strengthening is forecast, and the system is forecast
to become a tropical storm later today.

The estimated minimum central pressure is 1012 mb (29.89 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are possible across Bermuda and
the nearby waters on Tuesday, particularly to the south of the
island.


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

$$
Forecaster Berg
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Re: ATL: EIGHT - Advisories

#4 Postby cycloneye » Mon Aug 16, 2021 9:47 am

BULLETIN
Tropical Depression Eight Advisory Number 3
NWS National Hurricane Center Miami FL AL082021
1100 AM AST Mon Aug 16 2021

...TROPICAL DEPRESSION ALMOST A TROPICAL STORM...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...31.3N 62.8W
ABOUT 135 MI...220 KM ESE OF BERMUDA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...S OR 185 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1012 MB...29.89 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Bermuda

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Tropical Depression Eight
was located near latitude 31.3 North, longitude 62.8 West. The
depression is moving toward the south near 9 mph (15 km/h). A slow
clockwise turn toward the southwest and then toward the west is
expected during the next few days. On the forecast track, the
center of the depression will move well to the south of Bermuda.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Some strengthening is forecast during the next few days, and the
depression is expected to become a tropical storm later today.

The estimated minimum central pressure is 1012 mb (29.89 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are possible across Bermuda and
the nearby waters on Tuesday, particularly to the south of the
island.


NEXT ADVISORY
-------------
Next intermediate advisory at 200 PM AST.
Next complete advisory at 500 PM AST.

$$
Forecaster Berg



Tropical Depression Eight Discussion Number 3
NWS National Hurricane Center Miami FL AL082021
1100 AM AST Mon Aug 16 2021

Although the center of the depression is embedded beneath deep
convection, Dvorak estimates from TAFB and SAB are not a consensus
T2.5 quite yet. Therefore, the depression is still estimated to be
producing maximum winds of 30 kt. Very warm waters and low to
moderate deep-layer shear are expected to support strengthening
during the next couple of days. After 48 hours, strong northerly to
northeasterly shear of 25-30 kt is likely halt any intensification.
For the most part, the NHC intensity forecast is very close to the
tightly clustered SHIPS, LGEM, HCCA, and IVCN aids. As we've seen
in several cases this year, the HWRF is a notable high outlier,
bringing the system to category 2 hurricane strength in 2-3 days.
Given the expected shear, that solution does not appear likely at
this point.

The depression has been moving southward, or 185/8 kt, and it is
expected to rotate around a mid-tropospheric high located over the
western Atlantic. Track models are in general agreement that the
system will make a clockwise loop in the coming days, with most of
the disagreement being in how sharp the turn will be. In part due
to the system's initial motion, the updated NHC track forecast now
shows a wider, sweeping loop and is close to the TVCA consensus aid.
It should be noted that the ECMWF and HCCA aids are even farther
south and show an even more gradual turn.

FORECAST POSITIONS AND MAX WINDS

INIT 16/1500Z 31.3N 62.8W 30 KT 35 MPH
12H 17/0000Z 30.6N 63.1W 35 KT 40 MPH
24H 17/1200Z 30.2N 63.8W 40 KT 45 MPH
36H 18/0000Z 29.9N 64.7W 45 KT 50 MPH
48H 18/1200Z 29.8N 66.0W 50 KT 60 MPH
60H 19/0000Z 29.9N 67.4W 55 KT 65 MPH
72H 19/1200Z 30.1N 68.7W 50 KT 60 MPH
96H 20/1200Z 31.0N 70.1W 45 KT 50 MPH
120H 21/1200Z 33.1N 69.2W 45 KT 50 MPH

$$
Forecaster Berg
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Re: ATL: EIGHT - Advisories

#5 Postby cycloneye » Mon Aug 16, 2021 12:45 pm

BULLETIN
Tropical Depression Eight Intermediate Advisory Number 3A
NWS National Hurricane Center Miami FL AL082021
200 PM AST Mon Aug 16 2021

...TROPICAL DEPRESSION STILL MOVING SOUTHWARD...


SUMMARY OF 200 PM AST...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...31.1N 62.8W
ABOUT 140 MI...225 KM SE OF BERMUDA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...S OR 185 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1012 MB...29.89 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Bermuda

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 200 PM AST (1800 UTC), the center of Tropical Depression Eight
was located near latitude 31.1 North, longitude 62.8 West. The
depression is moving toward the south near 9 mph (15 km/h). A slow
clockwise turn toward the southwest and then toward the west is
expected during the next few days. On the forecast track, the
center of the depression will move well to the south of Bermuda.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Some strengthening is forecast during the next few days, and the
depression is expected to become a tropical storm later today or
tonight.

The estimated minimum central pressure is 1012 mb (29.89 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are possible across Bermuda and
the nearby waters on Tuesday, particularly to the south of the
island.


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

$$
Forecaster Berg
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Re: ATL: HENRI - Advisories

#6 Postby cycloneye » Mon Aug 16, 2021 3:49 pm

TCPAT3

BULLETIN
Tropical Storm Henri Advisory Number 4
NWS National Hurricane Center Miami FL AL082021
500 PM AST Mon Aug 16 2021

...TROPICAL DEPRESSION STRENGTHENS INTO TROPICAL STORM HENRI...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...31.0N 62.9W
ABOUT 145 MI...230 KM SE OF BERMUDA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...SSW OR 200 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1010 MB...29.83 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Bermuda

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Storm Henri was
located near latitude 31.0 North, longitude 62.9 West. Henri is
moving toward the south-southwest near 7 mph (11 km/h). A slow
clockwise turn toward the southwest and then toward the west is
expected during the next day or two. On the forecast track, the
center of Henri should pass well to the south of Bermuda late
Tuesday or Tuesday night.

Maximum sustained winds have increased to near 40 mph (65 km/h)
with higher gusts. Some additional strengthening is forecast during
the next couple of days.

Henri is a small tropical cyclone. Tropical-storm-force winds
only extend outward up to 35 miles (55 km) from the center.

The estimated minimum central pressure is 1010 mb (29.83 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are possible across Bermuda and
the nearby waters on Tuesday, particularly to the south of the
island.


NEXT ADVISORY
-------------
Next intermediate advisory at 800 PM AST.
Next complete advisory at 1100 PM AST.

$$
Forecaster Brown


Tropical Storm Henri Discussion Number 4
NWS National Hurricane Center Miami FL AL082021
500 PM AST Mon Aug 16 2021

Deep convection has persisted near and southeast of the center
of the small tropical cyclone today, and subjective Dvorak
intensity estimates were a consensus T2.5 (35 kt) at 1800 UTC.
Objective estimates from ADT and SATCON also support tropical
storm status, therefore the depression has been upgraded to a
35-kt tropical storm with this advisory. Henri (ahn-REE) becomes
the eighth named storm of the 2021 Atlantic hurricane season. This
is the fourth-earliest eighth storm on record with only 2020,
2005, and 1936 having the eighth-named storm form earlier in the
season.

Henri is located over warm waters, but is currently being affected
by light to moderate northerly shear and dry mid-level air in the
surrounding environment. Although these conditions are not overly
conducive for strengthening, most of the intensity guidance
supports gradual intensification over the next 24 to 48 hours.
After that time, a significant increase in northeasterly
upper-level winds is depicted by the global models over the system,
which is likely to halt further strengthening. In fact, given the
small size of Henri, it is likely to be more susceptible to the
increase in shear, and it could weaken faster than indicated below.
The HWRF remains more aggressive, but given the expected increase in
shear, that solution still does not seem likely. The NHC intensity
forecast is in best agreement with the LGEM model, and is slightly
below the IVCN intensity consensus.

The tropical storm is moving south-southwestward or 200/6 kt. Henri
is forecast to move west-southwestward during the next 12-24 hours
around the southeastern side of a mid-tropospheric high over the
western Atlantic. After that time, Henri should turn westward as
the ridge shifts eastward to the north of the tropical cyclone, and
after 72 hours Henri is expected to approach the western extent of
the ridge and should turn northward and then north-northeastward.
The dynamical model guidance is in somewhat better agreement during
the next 48-72 hours, but there remains some spread later in
the period as to how sharp of northward turn occurs. The new NHC
track forecast is similar to the previous advisory and lies near
the center of the guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT 16/2100Z 31.0N 62.9W 35 KT 40 MPH
12H 17/0600Z 30.5N 63.4W 40 KT 45 MPH
24H 17/1800Z 30.3N 64.2W 45 KT 50 MPH
36H 18/0600Z 30.2N 65.4W 50 KT 60 MPH
48H 18/1800Z 30.2N 66.9W 50 KT 60 MPH
60H 19/0600Z 30.3N 68.5W 50 KT 60 MPH
72H 19/1800Z 30.5N 69.9W 45 KT 50 MPH
96H 20/1800Z 31.8N 70.2W 45 KT 50 MPH
120H 21/1800Z 34.2N 68.4W 45 KT 50 MPH

$$
Forecaster Brown
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Re: ATL: HENRI - Advisories

#7 Postby cycloneye » Mon Aug 16, 2021 6:47 pm

BULLETIN
Tropical Storm Henri Intermediate Advisory Number 4A
NWS National Hurricane Center Miami FL AL082021
800 PM AST Mon Aug 16 2021

...HENRI MOVING SLOWLY SOUTH-SOUTHWESTWARD...


SUMMARY OF 800 PM AST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...30.9N 63.0W
ABOUT 145 MI...230 KM SE OF BERMUDA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...SSW OR 205 DEGREES AT 5 MPH...7 KM/H
MINIMUM CENTRAL PRESSURE...1010 MB...29.83 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Bermuda

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 800 PM AST (0000 UTC), the center of Tropical Storm Henri was
located near latitude 30.9 North, longitude 63.0 West. Henri is
moving toward the south-southwest near 5 mph (7 km/h). A slow
clockwise turn toward the southwest and then toward the west is
expected during the next day or two. On the forecast track, the
center of Henri should pass well to the south of Bermuda late
Tuesday or Tuesday night.

Maximum sustained winds are near 40 mph (65 km/h) with higher
gusts. Some strengthening is forecast during the next couple of
days.

Henri is a small tropical cyclone. Tropical-storm-force winds only
extend outward up to 35 miles (55 km) from the center.

The estimated minimum central pressure is 1010 mb (29.83 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are possible across Bermuda and
the nearby waters on Tuesday, particularly to the south of the
island.


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

$$
Forecaster Brown
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Re: ATL: HENRI - Advisories

#8 Postby cycloneye » Mon Aug 16, 2021 9:45 pm

BULLETIN
Tropical Storm Henri Advisory Number 5
NWS National Hurricane Center Miami FL AL082021
1100 PM AST Mon Aug 16 2021

...HENRI A LITTLE STRONGER...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...30.7N 63.3W
ABOUT 140 MI...230 KM SE OF BERMUDA
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...SW OR 215 DEGREES AT 5 MPH...7 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Bermuda

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Tropical Storm Henri was
located near latitude 30.7 North, longitude 63.3 West. Henri is
moving toward the southwest near 5 mph (7 km/h), and this motion
should continue through Tuesday morning. A turn toward the west is
is forecast by Tuesday night, and a slightly faster westward motion
should continue through early Thursday. On the forecast track, the
center of Henri should pass well to the south of Bermuda late
Tuesday or Tuesday night.

Maximum sustained winds have increased to near 45 mph (75 km/h)
with higher gusts. Some additional strengthening is possible
during the next day or so.

Henri is a small tropical cyclone. Tropical-storm-force winds
extend outward only up to 35 miles (55 km) from the center.

The estimated minimum central pressure is 1008 mb (29.77 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are possible across Bermuda and
the nearby waters on Tuesday, particularly to the south of the
island.


NEXT ADVISORY
-------------
Next intermediate advisory at 200 AM AST.
Next complete advisory at 500 AM AST.

$$
Forecaster Brown




Tropical Storm Henri Discussion Number 5
NWS National Hurricane Center Miami FL AL082021
1100 PM AST Mon Aug 16 2021

Bursts of deep convection continue to pulse over the southeastern
portion of Henri's circulation. Although the tropical cyclone is
still being affected by dry-air entrainment and light-to-moderate
shear, the latest subjective and objective satellite intensity
estimates are a little higher than before, and a blend of those
estimates yields an initial wind speed of 40 kt for this advisory.
Henri is forecast to remain over SSTs of 28-29C throughout the
forecast period, but the mid-level relative humidity is forecast
to remain fairly dry, which is likely to only support gradual
strengthening over the next day or so. After that time, a
significant increase in northeasterly shear is anticipated, and
that is likely to stop further strengthening. As mentioned in the
previous advisory, given the small size of Henri, the tropical
cyclone is likely to be more susceptible to this shear and it is
possible that Henri weakens more than indicated below by day 3. The
NHC intensity forecast is a blend of the various statistical aids,
and the CTCI and HMNI models. Less weight is again placed on the
HWRF model, which remains quite aggressive in strengthening Henri
over the next several days despite the expected increase in shear
and dry mid-level environment.

Henri is moving southwestward or 215/4 kt. The tropical storm is
forecast to move in a counterclockwise motion over the next several
days as it moves around a mid-tropospheric high that is forecast
to shift eastward over the western Atlantic. This motion should
take Henri south of Bermuda late Tuesday or Tuesday night. By 72
hours, the storm is expected to reach the western extent of the
ridge and turn northward, and then northeastward by the end of
the forecast period. There is still some spread in the guidance
as to when and how sharp the turn will be. As a result, the NHC
track forecast is a blend of the typically reliable GFS and ECMWF
models later in the period.


FORECAST POSITIONS AND MAX WINDS

INIT 17/0300Z 30.7N 63.3W 40 KT 45 MPH
12H 17/1200Z 30.5N 63.8W 45 KT 50 MPH
24H 18/0000Z 30.4N 64.8W 50 KT 60 MPH
36H 18/1200Z 30.3N 66.2W 50 KT 60 MPH
48H 19/0000Z 30.3N 67.8W 50 KT 60 MPH
60H 19/1200Z 30.5N 69.3W 50 KT 60 MPH
72H 20/0000Z 31.3N 70.1W 45 KT 50 MPH
96H 21/0000Z 32.8N 69.7W 45 KT 50 MPH
120H 22/0000Z 35.0N 66.5W 45 KT 50 MPH

$$
Forecaster Brown
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Re: ATL: HENRI - Advisories

#9 Postby cycloneye » Tue Aug 17, 2021 3:38 am

Tropical Storm Henri Discussion Number 6
NWS National Hurricane Center Miami FL AL082021
500 AM AST Tue Aug 17 2021

Earlier this evening Henri was undergoing a sheared bursting
pattern, with intermittent deep convection trying to develop near
the center, but northwesterly shear would quickly diminish the
convective coverage. However, over the past several hours the
convection has become more persistent, and covers at least the
southeastern portion of the low-level center. As such, the latest
subjective Dvorak intensity estimates from TAFB and SAB are now
both 3.0 (45 kt), and therefore 45 kt will be the initial advisory
intensity.

Henri is forecast to remain over warm waters and in an environment
of light to moderate northerly shear for the next 24 h, so some
strengthening is expected during that time. After 24 h, global
models indicate that the shear magnitude will double, which should
prevent any further strengthening and possibly weaken the cyclone.
The latest NHC intensity forecast was adjusted a little higher than
the previous due to both the increase in initial intensity, and
slight increase in the model intensity guidance. This forecast
closely follows the LGEM solution and is just a little lower than
the IVCN consensus.

The tropical storm continues to move slowly southwest, or 240/04 kt
to the southeast of a mid-level ridge. This ridge is forecast to
shift to the east over the next several days, which would result in
the tropical storm making a gradual clockwise turn throughout much
of the forecast period. Tonight, Henri is forecast to turn westward
with a increase in forward motion and pass well south of Bermuda. In
a few days, the cyclone should turn to the northwest then north,
followed by a turn to the northeast around the western periphery of
the ridge. There continues to be some spread in how far west Henri
will go before it begins to turn to the north, and the latest
guidance has made a slight shift to the left. The official NHC
forecast is near the previous one through 48 h, then is a little
left of it thereafter, yet still remains to the right of the bulk of
the consensus guidance beyond 48 h.


FORECAST POSITIONS AND MAX WINDS

INIT 17/0900Z 30.6N 63.7W 45 KT 50 MPH
12H 17/1800Z 30.4N 64.4W 50 KT 60 MPH
24H 18/0600Z 30.3N 65.7W 55 KT 65 MPH
36H 18/1800Z 30.2N 67.1W 55 KT 65 MPH
48H 19/0600Z 30.3N 68.6W 55 KT 65 MPH
60H 19/1800Z 30.8N 69.8W 55 KT 65 MPH
72H 20/0600Z 31.6N 70.6W 55 KT 65 MPH
96H 21/0600Z 34.0N 69.1W 55 KT 65 MPH
120H 22/0600Z 36.0N 66.0W 55 KT 65 MPH

$$
Forecaster Latto
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Re: ATL: HENRI - Advisories

#10 Postby cycloneye » Tue Aug 17, 2021 9:40 am

Tropical Storm Henri Discussion Number 7
NWS National Hurricane Center Miami FL AL082021
1100 AM AST Tue Aug 17 2021

Henri remains a sheared tropical storm. Geostationary satellite
images and microwave data show a relatively large area of deep
convection (~200 miles across), but the center of the storm is
located near the western edge of the thunderstorms due to ongoing
northwesterly vertical wind shear. The latest Dvorak estimates have
been steady at 3.0/45 kt from TAFB and SAB, and based on that data,
the initial intensity is held at 45 kt. The center of Henri is
located roughly 130 miles south-southeast of Bermuda currently, and
this will likely be as close as the storm gets to the island.

The tropical storm is gradually turning to the west, as expected,
and the initial motion is estimated to be 255/5 kt. A subtropical
ridge over the western Atlantic is building eastward to the north of
Henri, and this feature should steer the storm westward at a
slightly faster pace during the next two or three days. After that
time, the ridge is expected to weaken and shift farther east as a
cut off low or negatively-tilted trough develops over the northeast
U.S. This change in the steering pattern should cause Henri to turn
northeastward between Bermuda and the east coast of the U.S in the
72-120 h period. The NHC track forecast is a little faster than the
previous one in the short term and farther west than the previous
one from days 3-5, trending toward the latest consensus models.

The northwesterly shear currently affecting Henri is expected to
subside later today, and that should allow the storm to gain
strength during the next 12-24 hours. However, a round of moderate
northerly shear is expected to setup over Henri during the 24-96
hour period. Although this shear would typically cause some
weakening, the combination of warm SSTs and increasing mid-level
moisture could offset the negative influences of the shear.
Therefore, no change in strength is predicted beyond the 24 h
period. Some of the models suggest that the shear could lessen
again this weekend, so although not explicitly forecast, some
strengthening is possible then.


FORECAST POSITIONS AND MAX WINDS

INIT 17/1500Z 30.4N 64.3W 45 KT 50 MPH
12H 18/0000Z 30.4N 65.1W 50 KT 60 MPH
24H 18/1200Z 30.3N 66.5W 55 KT 65 MPH
36H 19/0000Z 30.3N 68.2W 55 KT 65 MPH
48H 19/1200Z 30.4N 69.7W 55 KT 65 MPH
60H 20/0000Z 30.7N 70.6W 55 KT 65 MPH
72H 20/1200Z 31.6N 71.3W 55 KT 65 MPH
96H 21/1200Z 34.1N 69.6W 55 KT 65 MPH
120H 22/1200Z 37.4N 66.0W 55 KT 65 MPH

$$
Forecaster Cangialosi
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Re: ATL: HENRI - Advisories

#11 Postby cycloneye » Tue Aug 17, 2021 1:02 pm

BULLETIN
Tropical Storm Henri Intermediate Advisory Number 7A
NWS National Hurricane Center Miami FL AL082021
200 PM AST Tue Aug 17 2021

...HENRI STRENGTHENS SLIGHTLY SOUTH-SOUTHEAST OF BERMUDA...


SUMMARY OF 200 PM AST...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...30.4N 64.3W
ABOUT 135 MI...215 KM SSE OF BERMUDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...WSW OR 255 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Bermuda

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, in this case within the next 24
hours.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 200 PM AST (1800 UTC), the center of Tropical Storm Henri was
located near latitude 30.4 North, longitude 64.3 West. Henri is
moving toward the west-southwest near 6 mph (9 km/h). A faster
motion toward the west is forecast by tonight, followed by a motion
to the west-northwest or northwest by late Thursday. On the forecast
track, the center of Henri should pass well to the south of Bermuda
through tonight.

Maximum sustained winds have increased to near 60 mph (95 km/h)
with higher gusts. Some additional strengthening is possible
during the next day or so.

Tropical-storm-force winds extend outward up to 35 miles (55 km)
from the center.

The estimated minimum central pressure is 1000 mb (29.53 inches).


HAZARDS AFFECTING LAND
----------------------
WIND: Tropical storm conditions are possible today across Bermuda
and the nearby waters, particularly to the south of the
island.

SURF: Swells generated by Henri are expected to affect Bermuda
during the next day or so. Please consult products from the Bermuda
Weather Service for more details.


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

$$
Forecaster Cangialosi
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Re: ATL: HENRI - Advisories

#12 Postby cycloneye » Tue Aug 17, 2021 3:41 pm

Tropical Storm Henri Discussion Number 8
NWS National Hurricane Center Miami FL AL082021
500 PM AST Tue Aug 17 2021

Henri appears to be gaining strength. Satellite images show banding
features becoming increasingly curved, especially on the east side
of the system, and an eye feature has been occasionally seen in
radar images from Bermuda. The upper-level outflow is also well
established to the north and east of the center. The center itself
is estimated to be located near the western edge of the convection,
but it is possible that a new center is forming farther east. The
initial intensity is raised to 55 kt following the Dvorak
classification from TAFB. The initial wind radii has been expanded
outward based on an earlier ASCAT pass.

The tropical storm appears to have slowed down, and the latest
initial motion estimate is 255/2 kt. A subtropical ridge over the
western Atlantic is building eastward to the north of Henri, and
this feature should steer the storm westward at a slightly faster
pace during the next two to three days. After that time, the ridge
is expected to weaken and shift farther east as a cut off low or
negatively-tilted trough develops over the northeast U.S. This
change in the steering pattern should cause Henri to turn
northeastward between Bermuda and the east coast of the U.S in the
72-120 h period. There is a fair amount of spread in exactly when
and where Henri makes this turn and the GFS and EC ensembles have
some members not far offshore of New England and Atlantic Canada.
Overall, the guidance has shifted westward again this cycle, and the
NHC track forecast has been adjusted accordingly from days 3 to 5.

The northwesterly shear currently affecting Henri is subsiding,
which should allow the storm to gain a little more strength tonight.
However, a round of moderate northerly shear is expected to setup
over Henri on Wednesday and Thursday and that will likely
temporarily end the opportunity for strengthening. Although this
shear would typically cause some weakening, the combination of warm
SSTs and increasing mid-level moisture could offset the negative
influences of the shear. By Friday and over the weekend, the shear
is expected to lessen again and since the other environmental
factors are predicted to remain favorable for the storm,
strengthening is shown from days 3-5. This forecast is above the
previous one, and lies fairly close to the middle of the guidance
envelope.


FORECAST POSITIONS AND MAX WINDS

INIT 17/2100Z 30.4N 64.2W 55 KT 65 MPH
12H 18/0600Z 30.3N 65.5W 60 KT 70 MPH
24H 18/1800Z 30.2N 67.0W 60 KT 70 MPH
36H 19/0600Z 30.2N 68.6W 60 KT 70 MPH
48H 19/1800Z 30.3N 70.0W 60 KT 70 MPH
60H 20/0600Z 31.0N 71.1W 60 KT 70 MPH
72H 20/1800Z 32.0N 71.5W 65 KT 75 MPH
96H 21/1800Z 35.5N 69.6W 70 KT 80 MPH
120H 22/1800Z 39.1N 65.2W 70 KT 80 MPH

$$
Forecaster Cangialosi
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Re: ATL: HENRI - Advisories

#13 Postby cycloneye » Tue Aug 17, 2021 9:57 pm

Tropical Storm Henri Discussion Number 8
NWS National Hurricane Center Miami FL AL082021
500 PM AST Tue Aug 17 2021

Henri appears to be gaining strength. Satellite images show banding
features becoming increasingly curved, especially on the east side
of the system, and an eye feature has been occasionally seen in
radar images from Bermuda. The upper-level outflow is also well
established to the north and east of the center. The center itself
is estimated to be located near the western edge of the convection,
but it is possible that a new center is forming farther east. The
initial intensity is raised to 55 kt following the Dvorak
classification from TAFB. The initial wind radii has been expanded
outward based on an earlier ASCAT pass.

The tropical storm appears to have slowed down, and the latest
initial motion estimate is 255/2 kt. A subtropical ridge over the
western Atlantic is building eastward to the north of Henri, and
this feature should steer the storm westward at a slightly faster
pace during the next two to three days. After that time, the ridge
is expected to weaken and shift farther east as a cut off low or
negatively-tilted trough develops over the northeast U.S. This
change in the steering pattern should cause Henri to turn
northeastward between Bermuda and the east coast of the U.S in the
72-120 h period. There is a fair amount of spread in exactly when
and where Henri makes this turn and the GFS and EC ensembles have
some members not far offshore of New England and Atlantic Canada.
Overall, the guidance has shifted westward again this cycle, and the
NHC track forecast has been adjusted accordingly from days 3 to 5.

The northwesterly shear currently affecting Henri is subsiding,
which should allow the storm to gain a little more strength tonight.
However, a round of moderate northerly shear is expected to setup
over Henri on Wednesday and Thursday and that will likely
temporarily end the opportunity for strengthening. Although this
shear would typically cause some weakening, the combination of warm
SSTs and increasing mid-level moisture could offset the negative
influences of the shear. By Friday and over the weekend, the shear
is expected to lessen again and since the other environmental
factors are predicted to remain favorable for the storm,
strengthening is shown from days 3-5. This forecast is above the
previous one, and lies fairly close to the middle of the guidance
envelope.


FORECAST POSITIONS AND MAX WINDS

INIT 17/2100Z 30.4N 64.2W 55 KT 65 MPH
12H 18/0600Z 30.3N 65.5W 60 KT 70 MPH
24H 18/1800Z 30.2N 67.0W 60 KT 70 MPH
36H 19/0600Z 30.2N 68.6W 60 KT 70 MPH
48H 19/1800Z 30.3N 70.0W 60 KT 70 MPH
60H 20/0600Z 31.0N 71.1W 60 KT 70 MPH
72H 20/1800Z 32.0N 71.5W 65 KT 75 MPH
96H 21/1800Z 35.5N 69.6W 70 KT 80 MPH
120H 22/1800Z 39.1N 65.2W 70 KT 80 MPH

$$
Forecaster Cangialosi
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Re: ATL: HENRI - Advisories

#14 Postby cycloneye » Wed Aug 18, 2021 3:58 am

Tropical Storm Henri Discussion Number 10
NWS National Hurricane Center Miami FL AL082021
500 AM AST Wed Aug 18 2021

There's been little change in Henri's satellite appearance this
morning. The surface center is still located just to the northwest
of a gradually expanding central dense overcast, and there still
appears to be an eye-like feature in the Bermuda Doppler radar
presentation. However, there are no indications in the GOES-16
BD-curve enhanced infrared images of a developing warm spot.
Subjective and objective satellite intensity estimates remain
steady, and the initial intensity is held at 55 kt for this
advisory.

Although the surrounding thermodynamic environment is ripe for
further significant development, moderate northwesterly shear
continues to impinge on the cyclone causing difficulty in inner-core
convective development. Consequently, little change in strength is
expected during the next couple days, and in fact the statistical
SHIPS model indicates an increase in a more northerly shear
component on Thursday. By Saturday afternoon, however, the shear
should decrease as the cyclone slides beneath an upper ridge axis
off of the southeast U.S. coast. Henri is expected to further
intensity through the remaining period as the upper-wind flow
becomes much more diffluent. The official intensity forecast is
similar to the previous advisory, and lies between the SHIPS model
and the HFIP Corrected Consensus Approach aid after the 60-hour
period.

The initial motion is estimated to be westward, or 260/7 kt. A high
amplitude mid- to upper-level anticyclone situated north-northeast
of Henri should steer the cyclone toward the west during the next 36
hours, or so. Thereafter, the aforementioned ridge is forecast to
weaken and shift eastward in response to a mid-latitude shortwave
trough moving over the northeastern U.S. As a result of the change
in the synoptic steering pattern, Henri should turn toward the
northwest, north, and then northeast through the remaining portion
of the forecast. With so much uncertainty or spread in the global
and regional models beyond day 3, the best approach at this point is
to base the NHC forecast on the better performing multi-model
consensus guidance, which has once again shifted a bit to the left
of the previous track forecast. I think it's worth noting that the
GFSv16 model is now showing a shortwave ridge building over
eastern Canada on Sunday, which causes Henri to move more northward
toward the New England coast. Therefore, additional changes or
shifts of the track beyond the 60-hour period may be required on
subsequent advisories.

Due to the increased uncertainty in the track forecast, interests
along the New England coast should monitor the progress of Henri.


FORECAST POSITIONS AND MAX WINDS

INIT 18/0900Z 30.1N 65.7W 55 KT 65 MPH
12H 18/1800Z 29.9N 66.9W 60 KT 70 MPH
24H 19/0600Z 29.8N 68.7W 60 KT 70 MPH
36H 19/1800Z 29.8N 70.6W 60 KT 70 MPH
48H 20/0600Z 30.4N 71.8W 60 KT 70 MPH
60H 20/1800Z 31.4N 72.3W 65 KT 75 MPH
72H 21/0600Z 33.0N 71.9W 70 KT 80 MPH
96H 22/0600Z 37.6N 69.0W 75 KT 85 MPH
120H 23/0600Z 40.5N 66.1W 65 KT 75 MPH

$$
Forecaster Roberts
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Re: ATL: HENRI - Advisories

#15 Postby cycloneye » Wed Aug 18, 2021 9:57 am

Tropical Storm Henri Discussion Number 11
NWS National Hurricane Center Miami FL AL082021
1100 AM AST Wed Aug 18 2021

Deep convection has been increasing during the past several hours in
association with Henri, and the cloud pattern mostly consists of a
central dense overcast with some fragmented bands around it. The
Dvorak estimates are steady at 3.5/55 kt from TAFB and SAB, and
therefore, the initial intensity is held at that value. However,
the latest automated Dvorak values from CIMSS at the University of
Wisconsin are higher, so it is possible that Henri could be slightly
stronger. An SSMIS pass from 1124 UTC showed some southward tilt
of the vortex with height and revealed a small mid-level eye
feature.

Henri continues to move just south of due west at 7 kt. The storm
is expected to move westward during the next day or so as it moves
in the flow on the south or southeast side of a mid-level ridge.
This ridge is expected to slide eastward by Friday as a mid- to
upper-level low develops over the Ohio Valley and northeastern U.S.
In response, Henri is expected to turn northward or north-
northeastward on Friday and continue in that direction through the
weekend. One complicating factor is that several of the models show
a ridge building over the northwestern Atlantic and Atlantic Canada,
which could cause the storm to stay on a more northward track closer
to New England than currently forecast. The spread in the models
for Henri's future track is quite large, with some guidance as far
west as Long Island and as far east as 62W longitude. Overall, the
models continue to walk left each cycle, and the NHC track forecast
has again been shifted in that direction. NOAA Gulfstream IV
missions and special weather balloon soundings have been scheduled,
and it is hoped that this additional data will help the models
handle the evolving steering pattern. Given the uncertainty in the
longer range track forecasts, users should be prepared for
additional adjustments to the NHC track forecast in future forecast
cycles.

The storm is currently in an environment of about 15-20 kt of
northerly wind shear according to the SHIPS model and analyses from
CIMSS at the University of Wisconsin. Since the shear is expected
to persist or become a little stronger during the next couple of
days, little change in strength is predicted during that time
period. After that time, the shear is expected to lessen and that
should allow Henri to strengthen to a hurricane by the weekend. Some
weakening is shown by the end of the period when Henri is forecast
to be moving over cooler waters. The NHC intensity forecast is
largely an update of the previous one and is just a little lower
than the consensus aids.

Key Messages:

1. Swells from Henri could reach much of the east coast of the U.S.
and Atlantic Canada by the end of the week and continue through the
weekend. These swells could cause life-threatening surf and rip
currents.

2. Uncertainty in the track forecast for Henri this weekend and
early next week is larger than usual, and there is some risk of
direct impacts from Henri in portions of the northeastern U.S. and
Atlantic Canada during that time. Interests in these areas should
follow updates to the forecast through the next several days.

FORECAST POSITIONS AND MAX WINDS

INIT 18/1500Z 30.0N 66.6W 55 KT 65 MPH
12H 19/0000Z 29.9N 67.9W 60 KT 70 MPH
24H 19/1200Z 29.8N 69.8W 60 KT 70 MPH
36H 20/0000Z 30.1N 71.4W 60 KT 70 MPH
48H 20/1200Z 30.7N 72.4W 60 KT 70 MPH
60H 21/0000Z 32.1N 72.5W 65 KT 75 MPH
72H 21/1200Z 34.2N 71.5W 75 KT 85 MPH
96H 22/1200Z 38.0N 69.6W 75 KT 85 MPH
120H 23/1200Z 41.0N 67.0W 65 KT 75 MPH

$$
Forecaster Cangialosi
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Re: ATL: HENRI - Advisories

#16 Postby cycloneye » Wed Aug 18, 2021 3:50 pm

BULLETIN
Tropical Storm Henri Advisory Number 12
NWS National Hurricane Center Miami FL AL082021
500 PM AST Wed Aug 18 2021

...HENRI ALMOST A HURRICANE...
...INTERESTS IN THE NORTHEASTERN U.S. SHOULD MONITOR ITS PROGRESS...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...29.9N 67.6W
ABOUT 235 MI...375 KM SW OF BERMUDA
ABOUT 790 MI...1275 KM S OF NANTUCKET MASSACHUSETTS
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...W OR 265 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...995 MB...29.39 INCHES


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

Interests in the northeastern U.S. and Atlantic Canada should
monitor the progress of Henri.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Storm Henri was
located near latitude 29.9 North, longitude 67.6 West. Henri is
moving toward the west near 9 mph (15 km/h) and this motion is
expected to continue for another day or so. A turn to the north is
expected on Friday with that motion continuing into the weekend.

Maximum sustained winds have increased to near 70 mph (110 km/h)
with higher gusts. Little change in strength is forecast during the
next day or so, but Henri is expected to become a hurricane on
Friday.

Tropical-storm-force winds extend outward up to 80 miles (130 km)
from the center.

The estimated minimum central pressure is 995 mb (29.39 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Henri should continue to affect Bermuda
during the next day or so. Swells are expected to increase across
much of the east coast of the U.S. and Atlantic Canada later this
week and this weekend. These swells could 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 Cangialosi




Tropical Storm Henri Discussion Number 12
NWS National Hurricane Center Miami FL AL082021
500 PM AST Wed Aug 18 2021

Henri appears a little better organized this afternoon. The storm
still has a central dense overcast pattern and there have been hints
of an eye evident in visible satellite images. Microwave images
continue to show a mid-level eye feature, but the storm does not
appear quite as well organized in the low-levels, and the vortex is
still titled southward with height. The latest Dvorak estimates
range from 55 to 67 kt, and based on that data the initial
intensity is nudged up to 60 kt, just below hurricane strength.

Henri is moving just south of due west at a slightly faster pace
now, 265/8 kt. The storm is expected to continue westward for
another 36 hours or so as it moves in the flow on the south side of
a mid-level ridge. A gradual turn to the north is forecast to begin
on Friday when a cutoff low forms over the Ohio Valley and the
northeastern U.S. This general northward motion should continue
through the weekend as another ridge builds to the east of Henri
over the northwestern Atlantic. The models continue their westward
shift, and the NHC track forecast has again been adjusted in that
direction and no longer shows a northeastward motion out to sea. In
particular, the westward adjustment at day 5 was a sizable 150
miles, and even with this shift the NHC forecast is still a little
to the east of some of the consensus aids. NOAA Gulfstream IV
missions and special weather balloon soundings have been scheduled,
and it is hoped that this additional data will help the models
handle the evolving steering pattern. Given the uncertainty in the
longer range track forecast, users should be prepared for additional
adjustments to the NHC track prediction in future forecast cycles.

The storm is currently in an environment of about 15-20 kt of
northerly wind shear according to the SHIPS model and analyses from
CIMSS at the University of Wisconsin, which is the reason the vortex
is currently titled. The shear should persist for another day or
so, and little change in strength seems likely during that time
period. However, strengthening is expected on Friday and Saturday
as the shear decreases while the storm remains over the Gulf Stream.
Some weakening seems likely at days 4 and 5 when the storm is
expected to be over cooler waters. The NHC intensity forecast lies
roughly near the middle of the guidance envelope and only minor
changes were made to the previous prediction.

Key Messages:

1. The forecast track of Henri has shifted toward the northeast
coast of the U.S. this weekend and early next week, increasing the
risk of direct storm surge, wind, and rain impacts in portions of
the northeastern U.S. and Atlantic Canada during that time.
Interests in these areas should closely follow the progress of
Henri and check for updates to the forecast.

2. Swells from Henri will begin to reach much of the east coast of
the U.S. and Atlantic Canada by the end of the week and continue
through the weekend. These swells could cause life-threatening surf
and rip currents.

FORECAST POSITIONS AND MAX WINDS

INIT 18/2100Z 29.9N 67.6W 60 KT 70 MPH
12H 19/0600Z 29.8N 69.0W 60 KT 70 MPH
24H 19/1800Z 29.8N 70.7W 60 KT 70 MPH
36H 20/0600Z 30.1N 72.3W 65 KT 75 MPH
48H 20/1800Z 31.0N 73.2W 70 KT 80 MPH
60H 21/0600Z 32.7N 72.7W 75 KT 85 MPH
72H 21/1800Z 35.2N 71.7W 80 KT 90 MPH
96H 22/1800Z 39.3N 70.0W 70 KT 80 MPH
120H 23/1800Z 41.4N 69.8W 60 KT 70 MPH

$$
Forecaster Cangialosi
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Re: ATL: HENRI - Advisories

#17 Postby cycloneye » Thu Aug 19, 2021 4:32 am

Tropical Storm Henri Discussion Number 14
NWS National Hurricane Center Miami FL AL082021
500 AM AST Thu Aug 19 2021

Compared to microwave images from earlier on Wednesday, GMI
microwave data from last evening revealed that Henri's structure
had deteriorated somewhat, with convection on the west side of the
mid-level eye having mostly dissipated. This degradation is likely
the result of strong deep-layer shear and dry air in the mid levels.
Satellite intensity estimates have either remained steady or
decreased a bit, and Henri's initial intensity is therefore held at
60 kt. This value is supported by two evening scatterometer passes,
which had peak winds of 52 kt and 57 kt.

The GMI and ASCAT data revealed that the center is slightly farther
south than previously estimated, and Henri has been moving south of
due west, or 260/8 kt. Water vapor imagery shows a shortwave trough
moving across the Great Lakes toward the Ohio Valley, and global
models are in agreement that this trough will cut off over the
central Appalachians in about 48 hours. As a result, the ridge
currently steering Henri westward is expected to relocate over the
northern Gulf coast, with the cut-off low causing Henri to
accelerate northward between Bermuda and the east coast of the
United States by late Friday through Sunday. Then, mid-level
ridging over Quebec is likely to cause Henri to slow down
considerably in the vicinity of southeastern New England or the
adjacent offshore waters by Monday. The latest suite of
deterministic track models have much less spread compared to on
Wednesday, with fairly good agreement on the scenario described
above. However, both the GEFS and ECMWF ensembles continue to show
a wider assortment of solutions, with stronger storms tending to
move closer to the U.S. coast and weaker storms moving farther
offshore. With the tight clustering of the current guidance, the
trajectory of the new NHC track forecast was not changed much from
the previous iteration, although it is a little faster during the
time that Henri accelerates to the north. The biggest point here is
that it's still too soon to know exactly how close Henri's center
will get to the coast of New England.

The north-northeasterly shear affecting Henri is not expected to
abate for another 24-36 hours. Once the shear does decrease,
however, warm waters should foster strengthening, up until Sunday
when Henri is expected to move north of the Gulf Stream. An
increase in southerly shear and Henri's slow motion over the colder
waters off New England should then cause weakening on days 4 and 5.
The NHC intensity forecast is a little below the HCCA and IVCN
consensus aids, which are being influenced by the seemingly
over-aggressive HWRF and COAMPS-TC models, and this new forecast is
very similar to the previous prediction.


Key Messages:

1. Henri is forecast to be near the northeast coast of the U.S.
late this weekend and early next week, and the risks of storm
surge, wind, and rain impacts in portions of the northeastern U.S.
and Atlantic Canada remains a distinct possibility. Interests in
these areas should closely follow the progress of Henri and check
for updates to the forecast.

2. Swells from Henri will begin to reach much of the east coast of
the U.S. and Atlantic Canada by the end of the week and continue
through the weekend. These swells could cause life-threatening surf
and rip currents.


FORECAST POSITIONS AND MAX WINDS

INIT 19/0900Z 29.5N 69.5W 60 KT 70 MPH
12H 19/1800Z 29.5N 70.9W 60 KT 70 MPH
24H 20/0600Z 29.9N 72.4W 60 KT 70 MPH
36H 20/1800Z 31.0N 73.0W 65 KT 75 MPH
48H 21/0600Z 33.0N 72.5W 75 KT 85 MPH
60H 21/1800Z 35.7N 71.4W 80 KT 90 MPH
72H 22/0600Z 38.2N 70.2W 80 KT 90 MPH
96H 23/0600Z 41.1N 69.3W 60 KT 70 MPH
120H 24/0600Z 42.0N 67.5W 50 KT 60 MPH

$$
Forecaster Berg
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Re: ATL: HENRI - Advisories

#18 Postby cycloneye » Thu Aug 19, 2021 9:52 am

Tropical Storm Henri Discussion Number 15
NWS National Hurricane Center Miami FL AL082021
1100 AM EDT Thu Aug 19 2021

Henri is not as well organized as it was yesterday. Microwave
images show that the vortex is titled to the south with height due
to about 25 kt of north-northeasterly wind shear. The system is
still producing a fair amount of deep convection, however, and the
cloud pattern resembles a central dense overcast with banding
features limited to the south side of the circulation. The Dvorak
estimates continue to range from 55 kt to 65 kt, and therefore, the
initial intensity is again held at 60 kt. The Air Force Reserve
Hurricane Hunters will be investigating Henri later today, and the
data the aircraft collects will be very helpful in assessing the
storm's structure and strength.

The tropical storm is moving just south of due west at 9 kt. Henri
is expected to move generally westward through tonight as the storm
remains on the south side of a mid-level ridge. On Friday, however,
a trough is expected to cut off over the Ohio Valley and
mid-Atlantic region of the U.S. while a ridge amplifies to the east
of Henri over the western Atlantic. A combination of these features
should cause Henri to turn northward on Friday and accelerate in
that direction over the weekend. By early next week, the ridge
is expected to weaken, which should cause Henri to turn more
toward the east. The models are in much better agreement than they
were yesterday and their solutions are clustering around southern
New England on Sunday and Monday. The NHC track forecast is just a
tad to the left of the previous one and lies near the typically
best-performing models, the various consensus aids. In addition
to the Air Force aircraft that flies through the storm, the NOAA
Gulfstream IV jet will also be flying around Henri later today to
help assess the environmental conditions and gather data for the
numerical models. It is hoped that these data will help the models
more accurately predict the future track of the storm.

The current north-northeasterly shear over Henri is forecast to
continue for about another day, and given the degraded structure of
the system it seems unlikely that the storm will strengthen during
that time period. However, the shear is expected to decrease on
Friday and it will remain quite low through the weekend.
Therefore, strengthening to a hurricane is expected during that
time period. Once Henri crosses the north wall of the Gulf Stream
in a few days, steady weakening is predicted. The NHC intensity
forecast is just an update of the previous one and lies near the
middle of the guidance envelope.

It should be noted that as Henri gains latitude and moves near
New England, the wind field is expected to expand. Therefore,
users are reminded to not focus on the exact forecast points as
impacts will extend far from the center.

Key Messages:

1. Henri is forecast to be near the northeast coast of the U.S.
on Sunday and Monday, and the risks of storm surge, wind, and rain
impacts in portions of southern New England and eastern Long Island
are increasing. Watches will likely be required for portions of
this area on Friday.

2. Swells from Henri will begin to reach much of the east coast of
the U.S. and Atlantic Canada by the end of the week and continue
through the weekend. These swells could cause life-threatening surf
and rip currents.

FORECAST POSITIONS AND MAX WINDS

INIT 19/1500Z 29.5N 70.5W 60 KT 70 MPH
12H 20/0000Z 29.7N 71.9W 60 KT 70 MPH
24H 20/1200Z 30.4N 72.9W 60 KT 70 MPH
36H 21/0000Z 31.9N 72.9W 65 KT 75 MPH
48H 21/1200Z 34.4N 72.0W 75 KT 85 MPH
60H 22/0000Z 37.3N 70.7W 80 KT 90 MPH
72H 22/1200Z 39.6N 70.0W 75 KT 85 MPH
96H 23/1200Z 41.6N 69.7W 55 KT 65 MPH
120H 24/1200Z 42.3N 67.0W 45 KT 50 MPH

$$
Forecaster Cangialosi
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Re: ATL: HENRI - Advisories

#19 Postby cycloneye » Thu Aug 19, 2021 3:41 pm

BULLETIN
Tropical Storm Henri Advisory Number 16
NWS National Hurricane Center Miami FL AL082021
500 PM EDT Thu Aug 19 2021

...HENRI EXPECTED TO STRENGTHEN ON FRIDAY AND OVER THE WEEKEND...
...INTERESTS IN THE NORTHEASTERN U.S. SHOULD MONITOR ITS PROGRESS...


SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...29.7N 71.4W
ABOUT 450 MI...720 KM SSE OF CAPE HATTERAS NORTH CAROLINA
ABOUT 800 MI...1285 KM S OF NANTUCKET MASSACHUSETTS
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES


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

Interests in the northeastern U.S. and Atlantic Canada should
monitor the progress of Henri. Watches will likely be required for
a portion of this area early Friday.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM EDT (2100 UTC), the center of Tropical Storm Henri was
located near latitude 29.7 North, longitude 71.4 West. Henri is
moving toward the west near 10 mph (17 km/h) and this motion is
expected to through tonight. A turn toward the northwest
is forecast on Friday, followed by an acceleration toward the north
and north-northeast Saturday and Sunday. On the forecast track, the
center of Henri will remain well offshore of the east coast of the
United States over the next couple of days, but it is forecast to be
near southern New England on Sunday and Monday.

Maximum sustained winds are near 65 mph (100 km/h) with higher
gusts. Little change in strength is expected during the next 12
to 24 hours, but Henri is forecast to intensify into a hurricane by
Friday night with additional strengthening expected this weekend.

Tropical-storm-force winds extend outward up to 90 miles (150 km)
from the center.

The estimated minimum central pressure is 997 mb (29.44 inches).


HAZARDS AFFECTING LAND
----------------------
RAINFALL: Henri may produce rainfall amounts of 2 to 5 inches over
southeastern New England Sunday into Monday, with isolated maximum
totals near 8 inches. Heavy rainfall from Henri may result in areas
of flash, urban, and small stream flooding.

SURF: Swells generated by Henri should continue to affect Bermuda
during the next day or so. Swells are expected to increase across
much of the east coast of the U.S. and Atlantic Canada later this
week and this weekend. These swells could cause life-threatening
surf and rip current conditions. Please consult products from your
local weather office.


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

$$
Forecaster Cangialosi




Tropical Storm Henri Discussion Number 16
NWS National Hurricane Center Miami FL AL082021
500 PM EDT Thu Aug 19 2021

The Air Force Hurricane Hunters investigated Henri earlier this
afternoon and found maximum flight-level winds and SFMR values to
support an intensity of about 55 kt and a minimum pressure of 997
mb. The storm's appearance in satellite images has been generally
steady throughout the day with the low-level center located on the
northern side of the convective mass, and banding features confined
to the south side of the circulation. This somewhat asymmetric
cloud pattern is due to about 25 kt of north-northeasterly shear.

The tropical storm is now moving due westward at 9 kt. A mid-level
ridge should keep Henri on a westward to west-northwestward track
through tonight. On Friday, however, a trough is expected to cut
off over the Ohio Valley and mid-Atlantic region of the U.S. while a
ridge amplifies to the east of Henri over the western Atlantic. A
combination of these features should cause Henri to turn northward
on Friday and accelerate in that direction over the weekend. The
exact location of the northward turn will be very critical in
determining Henri's future track and how close it gets to New
England. The latest GFS run has shifted eastward and the UKMET and
ECMWF have shifted westward. Consequently, the net result is very
little change in the consensus models and the new NHC track
forecast is just a little faster than the previous one. Based on
this forecast, Henri is expected to be very near southern New
England on Sunday and Monday. The NOAA Gulfstream IV jet will be
flying around Henri this evening to help assess the environmental
conditions and gather data for the numerical models. It is hoped
that these data will help the models more accurately predict the
future track of the storm.

Although Henri is a bit weaker now, the overall intensity forecast
philosophy has not changed. The shear is expected to persist for
another 12 to 24 hours, so little change in strength seems likely
during that time period. However, the global models show a more
conducive upper-level wind pattern over Henri shortly after that,
and in fact, all of the environmental conditions appear favorable
for strengthening on Friday and Saturday. Therefore, steady
intensification is expected during the 24-60 h time period, and
Henri is forecast to become a hurricane during that time. Henri is
expected to cross the north wall of the Gulf Stream and move over
much cooler SSTs on Sunday, and that should end the opportunity for
strengthening and induce a steady weakening trend from days 3 to 5.
Post-tropical transition is now shown to occur by the end of the
forecast period when Henri is expected to be over SSTs below 20
deg C.

It should be noted that as Henri gains latitude and moves near
New England, the wind field is expected to expand. Therefore,
users are reminded to not focus on the exact forecast points as
impacts will extend far from the center.

Key Messages:

1. Henri is forecast to be near the northeast coast of the U.S.
on Sunday and Monday, and the risks of storm surge, wind, and rain
impacts in portions of southern New England and eastern Long Island
are increasing. Watches will likely be required for portions of
this area early Friday.

2. Swells from Henri will begin to reach much of the east coast of
the U.S. and Atlantic Canada by the end of the week and continue
through the weekend. These swells could cause life-threatening surf
and rip currents.

3. Heavy rainfall may lead to flash, urban, and small stream
flooding over portions of southeastern New England Sunday into
Monday.


FORECAST POSITIONS AND MAX WINDS

INIT 19/2100Z 29.7N 71.4W 55 KT 65 MPH
12H 20/0600Z 30.1N 72.6W 55 KT 65 MPH
24H 20/1800Z 31.0N 73.2W 55 KT 65 MPH
36H 21/0600Z 33.0N 72.6W 65 KT 75 MPH
48H 21/1800Z 36.0N 71.3W 75 KT 85 MPH
60H 22/0600Z 38.9N 70.3W 80 KT 90 MPH
72H 22/1800Z 40.8N 70.1W 65 KT 75 MPH
96H 23/1800Z 42.3N 69.6W 50 KT 60 MPH
120H 24/1800Z 43.6N 65.7W 40 KT 45 MPH...POST-TROPICAL

$$
Forecaster Cangialosi
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Re: ATL: HENRI - Advisories

#20 Postby cycloneye » Thu Aug 19, 2021 10:06 pm

Tropical Storm Henri Discussion Number 17
NWS National Hurricane Center Miami FL AL082021
1100 PM EDT Thu Aug 19 2021

The satellite presentation on Henri this evening continues to
exhibit a persistent bursting pattern, with the center estimated to
be just to the north and west of the coldest cloud tops which
occasionally have been below -80 C in the overshooting tops. This
current satellite presentation is primarily due to continued
moderate to strong northerly vertical wind shear, which is forcing
the convection underneath the cirrus canopy down-shear of the
low-level center, as seen on a 2230 UTC SSMIS microwave pass. While
the mid-level vortex with the convection also remains tilted
down-shear of the low-level center, it has not completely separated
due to the persistent convection, preventing the low-level center
from escaping poleward in more shallow low-level steering.
Tonight's subjective Dvorak estimates from SAB/TAFB are in
agreement with T3.5/55 kt and given that this value is near what
the earlier Air Force Reconnaissance mission found, the latest
intensity is being maintained at 55 kt for this advisory.

There is a bit of uncertainty determining if Henri has begun a more
poleward motion since the center remains under the convective cirrus
plume, but my best guess is now 285/9 kt. Over the next 12-24 hours,
the mid- to upper-level ridging that has dominated the synoptic
steering pattern for Henri the last few days will quickly break
down, as a shortwave trough drops in from the Great Lakes into the
Mid-Atlantic and cuts off. This feature is now forecast to continue
digging in to the west of Henri. To the east, a new mid-level ridge
is also forecast to build in to the right of Henri. This synoptic
pattern should draw the cyclone poleward with an acceleration to the
north-northeast in the 24-48 h period. Afterwards, the
aforementioned trough takes on a negative tilt to the southwest of
Henri, helping to reorient the mid- to upper-level flow out of the
south-southeast, and this flow could result in a slight leftward
bend in the track between 48-72 h. The majority of guidance this
cycle now is forecasting the mid-level ridge east of Henri to build
poleward with the storm, blocking an easy path for the storm to stay
on a more northeast heading out to sea. Consequently, the latest NHC
forecast track now explicitly shows landfall in southeast
Massachusetts at 72 h. The track guidance this cycle has come into
better agreement, though there remain some leftward (UKMET) and
rightward (ECMWF) outliers. The latest forecast track lies very
close to the HFIP corrected consensus approach (HCCA) guidance,
which is also very near the latest GFS forecast track.

Data from the NOAA G-IV synoptic mission around Henri shows that
just north of the tropical cyclone there remains some very dry
mid-latitude air, which is being advected into the storm by 20-25
kt of northerly vertical wind shear. Over the next 24-36 hours,
this shear is forecast to gradual subside, as Henri moves near the
center of an upper-level ridge axis. By 36-48 hours, the vertical
wind shear is forecast to be under 10-kt by both the GFS- and
ECWMF-based SHIPS guidance, while the storm is also traversing
28-29 C sea-surface temperatures (SSTs). Thus, the latest NHC
intensity forecast still calls for strengthening beginning after 12
hours, and the rate of strengthening could be a bit quicker as the
storm moves over the warm gulf stream waters between 36-48 hours.
Thereafter, Henri will cross a very sharp SST gradient with
sea-surface temperatures down below 23 C near the New England coast
to the east of Long Island. Henri is forecast to begin weakening
after 48 hours, but the storm could still be near hurricane
intensity by the time Henri is forecast to be near the Northeast
coastline. Transition to a post-tropical storm is expected to begin
shortly thereafter which should be sometime in the 96-h to 120-h
points as deep convection ceases over the storm over cold SSTs

As noted previously, the wind field of Henri is expected to expand,
especially as it interacts with a mid-latitude trough located to its
west. Therefore, users are reminded to not focus on the exact
forecast points as impacts will extend far from the center.

Key Messages:

1. Henri is forecast to be near the northeast coast of the U.S.
on Sunday and Monday, and the risks of storm surge, wind, and rain
impacts in portions of southern New England and eastern Long Island
are increasing. Watches will likely be required for portions of
this area early Friday.

2. Swells from Henri will begin to reach much of the east coast of
the U.S. and Atlantic Canada by the end of the week and continue
through the weekend. These swells could cause life-threatening surf
and rip currents.

3. Heavy rainfall may lead to flash, urban, and small stream
flooding over portions of southeastern New England Sunday into
Monday.


FORECAST POSITIONS AND MAX WINDS

INIT 20/0300Z 29.8N 72.3W 55 KT 65 MPH
12H 20/1200Z 30.3N 73.2W 55 KT 65 MPH
24H 21/0000Z 31.8N 73.3W 60 KT 70 MPH
36H 21/1200Z 34.4N 72.2W 65 KT 75 MPH
48H 22/0000Z 37.6N 71.0W 80 KT 90 MPH
60H 22/1200Z 40.1N 70.6W 75 KT 85 MPH
72H 23/0000Z 41.7N 70.8W 60 KT 70 MPH...INLAND
96H 24/0000Z 42.5N 70.1W 40 KT 45 MPH...OVER WATER
120H 25/0000Z 43.7N 65.4W 35 KT 40 MPH...POST-TROPICAL

$$
Forecaster Papin/Brown
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