ATL: FRANKLIN - Advisories

[cycloneye]

BULLETIN
Tropical Storm Franklin Intermediate Advisory Number 14A
NWS National Hurricane Center Miami FL AL082023
200 AM EDT Thu Aug 24 2023

...FRANKLIN SLOWLY STRENGTHENING...
...HEAVY RAINS STILL AFFECTING PORTIONS OF THE DOMINICAN REPUBLIC...


SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION
----------------------------------------------
LOCATION...21.6N 70.5W
ABOUT 40 MI...60 KM E OF GRAND TURK ISLAND
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...NNE OR 15 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES


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

None.

BULLETIN
Tropical Storm Franklin Advisory Number 15
NWS National Hurricane Center Miami FL AL082023
500 AM EDT Thu Aug 24 2023

...FRANKLIN PULLING AWAY FROM THE TURKS AND CAICOS...
...FORECAST TO STRENGTHEN...


SUMMARY OF 500 AM EDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...21.9N 70.4W
ABOUT 55 MI...85 KM ENE OF GRAND TURK ISLAND
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES


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

The government of the Bahamas has discontinued the Tropical Storm
Warning for the Turks and Caicos.

The government of the Dominican Republic has discontinued all
Tropical Storm Warnings for the Dominican Republic.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

There are no coastal watches or warnings in effect.



Tropical Storm Franklin Discussion Number 15
NWS National Hurricane Center Miami FL AL082023
500 AM EDT Thu Aug 24 2023

Franklin is pulling away from the Dominican Republic and the Turks
and Caicos, and appears to be gradually gaining strength. Satellite
images show deep convection increasing near and to the east of the
center, and the Air Force Hurricane Hunters reported that a partial
eyewall was developing on their last pass through the storm. The
initial intensity of 45 kt is based on the earlier reconnaissance
data and is also near the average of the various satellite intensity
estimates.

The tropical storm is moving northward at 11 kt and is being steered
by the western periphery of a mid-level ridge that is centered over
the central subtropical Atlantic. The ridge is expected to weaken
soon, and that should cause Franklin to turn northeastward and slow
down during the next couple of days. However, beyond that time, the
models show the ridge building back to the west, and the flow
between that feature and a mid- to upper-level trough over the
eastern U.S. should cause Franklin to bend back northward at a
slightly faster pace. The models have shifted a little to the left
this cycle, and the NHC track forecast has been nudged in that
direction and takes the system to the west of Bermuda early next
week.

Franklin appears to be on a gradual strengthening trend, and that is
expected to continue through the weekend as the storm remains over
warm waters, in a moist environment, and in generally moderate wind
shear conditions. All of the normally skillful intensity models
bring Franklin to hurricane strength in a few days, and the NHC
intensity forecast follows that theme. This forecast is similar to
the previous one and near the high end of the model guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 24/0900Z 21.9N 70.4W 45 KT 50 MPH
12H 24/1800Z 22.6N 69.5W 50 KT 60 MPH
24H 25/0600Z 23.2N 68.1W 55 KT 65 MPH
36H 25/1800Z 23.5N 67.0W 55 KT 65 MPH
48H 26/0600Z 24.0N 66.3W 60 KT 70 MPH
60H 26/1800Z 24.9N 66.4W 65 KT 75 MPH
72H 27/0600Z 26.0N 67.0W 75 KT 85 MPH
96H 28/0600Z 29.4N 68.0W 95 KT 110 MPH
120H 29/0600Z 33.5N 68.0W 95 KT 110 MPH

$$
Forecaster Cangialosi

[cycloneye]

BULLETIN
Tropical Storm Franklin Advisory Number 16
NWS National Hurricane Center Miami FL AL082023
1100 AM AST Thu Aug 24 2023

...FRANKLIN STRENGTHENS A LITTLE...
...EXPECTED TO BECOME A HURRICANE IN A COUPLE OF DAYS...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...22.2N 69.9W
ABOUT 90 MI...145 KM ENE OF GRAND TURK ISLAND
ABOUT 765 MI...1230 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NE OR 40 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES


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


Tropical Storm Franklin Discussion Number 16
NWS National Hurricane Center Miami FL AL082023
1100 AM AST Thu Aug 24 2023

Franklin appears a little better organized this morning, with a
recent convective burst near the center with cloud tops as cold as
-80C. The morning Air Force Reserve Reconnaissance mission into
Franklin indicates the storm has intensified a bit, with peak flight
level winds of 62 kt at 850-mb, SFMR winds in the 50-55 kt range,
and a recent dropsonde just to the northeast of the center reported
a surface wind of 48 kt. The initial intensity based on this
data is set at 50 kt for this advisory.

Fixes from the aircraft indicate that Franklin has begun to move to
the northeast, with the motion estimated at 040/6 kt. This motion,
or even a bit more of a turn to the east-northeast, should continue
in the short-term as a weakness persists to the north of Franklin
and its motion is more driven by a weak mid-level ridge over the
eastern Caribbean Sea. By 48 hours, however, the mid-level ridging
is expected to become more pronounced east of the storm, leading to
a sharp turn to the north. The biggest change in the guidance this
cycle is a slower motion, especially in the first 48-60 hours. The
latest NHC track forecast is also slower, but not quite as slow as
the TVCN and HCCA consensus aids in this time period. Later on, the
track guidance continues to exhibit a fair amount of across track
spread in a west-to-east fashion. The ECMWF remains on the left side
of this guidance envelope, while the hurricane-regional models and
GFS remain on the right side. For now, the NHC track will favor the
right side of the guidance envelope, which happens to be near the
prior track forecast and HCCA consensus aid. On the forecast track,
Franklin should be passing by several hundred miles west of Bermuda
between days 4-5.

Franklin is continuing to gradually intensify this morning based on
the in-situ aircraft data. However, from the satellite structure,
the storm remains quite asymmetric due to about 20 kt of westerly
vertical wind shear. This shear is expected to persist for at least
another 36 hours, and only slow intensification is forecast over
this time span. After that, a much more favorable upper-level
pattern takes shape as an upper-level low cuts off to the southwest
of the tropical cyclone, and most of the guidance responds to this
change by showing more significant intensification. The NHC
intensity forecast follows this solution, bringing Franklin to near
major hurricane intensity in 96h, which remains near the higher end
of the intensity guidance this cycle.


FORECAST POSITIONS AND MAX WINDS

INIT 24/1500Z 22.2N 69.9W 50 KT 60 MPH
12H 25/0000Z 22.6N 68.9W 55 KT 65 MPH
24H 25/1200Z 23.0N 67.7W 55 KT 65 MPH
36H 26/0000Z 23.4N 66.9W 60 KT 70 MPH
48H 26/1200Z 23.9N 66.4W 65 KT 75 MPH
60H 27/0000Z 25.0N 66.6W 70 KT 80 MPH
72H 27/1200Z 26.6N 67.3W 80 KT 90 MPH
96H 28/1200Z 30.0N 68.5W 95 KT 110 MPH
120H 29/1200Z 34.5N 67.5W 90 KT 105 MPH

$$
Forecaster Papin

[cycloneye]

BULLETIN
Tropical Storm Franklin Advisory Number 17
NWS National Hurricane Center Miami FL AL082023
500 PM AST Thu Aug 24 2023

...FRANKLIN NOW MOVING EAST-NORTHEASTWARD...
...FORECAST TO BECOME A HURRICANE BY THE WEEKEND...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...22.4N 68.9W
ABOUT 155 MI...250 KM ENE OF GRAND TURK ISLAND
ABOUT 730 MI...1170 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES


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


Tropical Storm Franklin Discussion Number 17
NWS National Hurricane Center Miami FL AL082023
500 PM AST Thu Aug 24 2023

Since the prior advisory, Franklin's appearance has not changed
appreciably, with deep convection continuing to pulse near and to
the east of the low-level circulation center. The last few center
fixes from the earlier Air Force Reserve Reconnaissance mission
showed the tropical storm has continued to turn eastward, though
some of this motion might also be a reflection of the center being
dragged in the general direction of the persistent convective
bursts. The initial intensity for this advisory remains at 50 kt,
out of respect of the earlier aircraft data, and is also close to
the latest UW-CIMSS ADT estimate. Another reconnaissance mission
will be in the storm tonight to provide an updated assessment of
Franklin.

As mentioned above, Franklin is now moving east-northeastward,
estimated at 060/6 kt. This relatively unusual motion for a tropical
cyclone in late August at such low latitude is a byproduct of a
large weakness still parked north of Franklin. This weakness is
thanks in part to a longwave trough, allowing the storm's motion to
be more influenced by a mid-level anticyclone currently located to
its south over the Caribbean Sea. After the next 24 hours or so, the
ridging begins to build in more to the east of the storm, resulting
in both a slowdown and sharp turn north or north-northwestward
between 24 to 48 hours. From there, Franklin takes a much more
climatological motion northward and then recurves
north-northeastward as it is steered between the subtropical ridge
to its west and a amplifying mid-latitude trough digging into the
Great Lakes region by the end of the forecast period. While there
remains some cross-track spread in the track guidance solutions as
Franklin makes its turn northward, both the latest ECMWF and GFS
solutions have closed the gap between their tracks, and the latest
NHC track only needed minor adjustments compared to the prior cycle.

As discussed this morning, Franklin is expected to slowly intensify
for the next 24-36 h as moderate vertical wind shear is expected to
be somewhat offset by warm 29-30 C sea-surface temperatures. After
Franklin makes its turn northward, a cutoff low is expected to drop
southwest of the storm, placing it in a more favorable upper-level
difluent flow pattern. The guidance this cycle is showing a bit
faster rate of intensification early on, so the intensity forecast
was raised slightly from 48-72 h, still showing a peak intensity
just shy of major hurricane intensity. This forecast is now in good
agreement with the HCCA corrected consensus aid, but is lower than
the more aggressive HAFS-A/B regional hurricane model forecasts.


FORECAST POSITIONS AND MAX WINDS

INIT 24/2100Z 22.4N 68.9W 50 KT 60 MPH
12H 25/0600Z 22.6N 68.1W 55 KT 65 MPH
24H 25/1800Z 23.1N 67.0W 55 KT 65 MPH
36H 26/0600Z 23.5N 66.6W 60 KT 70 MPH
48H 26/1800Z 24.3N 66.5W 70 KT 80 MPH
60H 27/0600Z 25.6N 67.1W 80 KT 90 MPH
72H 27/1800Z 27.3N 67.7W 95 KT 110 MPH
96H 28/1800Z 31.0N 68.3W 95 KT 110 MPH
120H 29/1800Z 35.4N 66.5W 85 KT 100 MPH

$$
Forecaster Papin

[cycloneye]

BULLETIN
Tropical Storm Franklin Advisory Number 18
NWS National Hurricane Center Miami FL AL082023
1100 PM AST Thu Aug 24 2023

...FRANKLIN FORECAST TO TURN NORTHWARD AND STRENGTHEN OVER THE
WESTERN ATLANTIC OVER THE WEEKEND...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...22.6N 68.3W
ABOUT 195 MI...315 KM ENE OF GRAND TURK ISLAND
ABOUT 705 MI...1130 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...ENE OR 70 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


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



Tropical Storm Franklin Discussion Number 18
NWS National Hurricane Center Miami FL AL082023
1100 PM AST Thu Aug 24 2023

Franklin is still a strongly sheared tropical storm, with deep
convection displaced to the east and southeast of the surface
center. An Air Force Reserve Hurricane Hunter mission flying at
700 mb this evening fixed a center within the strong thunderstorm
activity, but because of the cyclone's tilted structure, the
surface center is estimated to be a few tenths of a degree farther
west. SFMR and flight-level winds suggest that the maximum winds
could be between 50-55 kt, but the central pressure has risen a few
millibars since this morning's flight. Therefore, the initial
intensity is held at 50 kt.

Franklin is embedded in the base of a deep-layer trough located
over the western Atlantic, which is steering the storm toward the
east-northeast (70 degrees) at 7 kt. The parent trough is forecast
to lift northeastward and allow mid-level ridging to build over the
central Atlantic during the next couple of days, and Franklin is
expected to respond by making a sharp but slow northward turn by 36
hours. The ridge could even be strong enough to push Franklin
toward the north-northwest for a time while the storm moves across
the western Atlantic, and the HAFS regional models in particular
favor that scenario, being the westernmost of the guidance suite.
Those models have tugged the consensus aids a bit west too, and as
a result the new NHC forecast track is nudged in that direction
compared to the previous forecast.

Moderate to strong deep-layer shear is likely to continue over
Franklin for the next 36-48 hours, until the storm makes its
northward turn. That said, warm ocean waters and a favorably
diffluent upper-level pattern should still allow for gradual
strengthening during the next couple of days, and Franklin is
expected to become a hurricane by 48 hours, about the time the shear
abates. More significant strengthening is likely after 48 hours
while Franklin moves over the western Atlantic, and the NHC
intensity forecast remains close to the HCCA and IVCN consensus
aids. The HAFS regional models continue to show stronger solutions,
so trends in the other models will have to be monitored for
potential upward adjustments to the official forecast in the coming
days.


FORECAST POSITIONS AND MAX WINDS

INIT 25/0300Z 22.6N 68.3W 50 KT 60 MPH
12H 25/1200Z 22.9N 67.5W 50 KT 60 MPH
24H 26/0000Z 23.2N 66.7W 55 KT 65 MPH
36H 26/1200Z 23.7N 66.6W 60 KT 70 MPH
48H 27/0000Z 24.8N 67.0W 65 KT 75 MPH
60H 27/1200Z 26.1N 67.7W 75 KT 85 MPH
72H 28/0000Z 27.8N 68.1W 90 KT 105 MPH
96H 29/0000Z 31.9N 68.2W 95 KT 110 MPH
120H 30/0000Z 37.1N 65.6W 85 KT 100 MPH

$$
Forecaster Berg

[cycloneye]

BULLETIN
Tropical Storm Franklin Advisory Number 19
NWS National Hurricane Center Miami FL AL082023
500 AM AST Fri Aug 25 2023

...FRANKLIN HOLDING STEADY BUT FORECAST TO STRENGTHEN THIS
WEEKEND...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...22.7N 68.0W
ABOUT 215 MI...345 KM ENE OF GRAND TURK ISLAND
ABOUT 690 MI...1110 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...ENE OR 75 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


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



Tropical Storm Franklin Discussion Number 19
NWS National Hurricane Center Miami FL AL082023
500 AM AST Fri Aug 25 2023

Franklin has generally changed little during the past several hours.
The storm remains strongly sheared with the low-level center
partially exposed near the western edge of the main area of deep
convection. Cloud tops are quite cold on the system's east side,
but the storm continues to lack convective symmetry. The initial
intensity remains 50 kt based on the earlier Air Force
reconnaissance data, which is a little above the current satellite
intensity estimates.

The storm is moving slowly to the east-northeast at about 5 kt in
weak steering currents near the base of a broad mid- to upper-level
trough. A north to north-northwest motion is expected to commence
tonight or early Saturday as ridging builds to the east of Franklin
over the central Atlantic. This motion should bring the core of the
system to the west of Bermuda on Monday and Tuesday. The storm is
likely to turn northeastward and accelerate by the middle of next
week when it should move in the faster flow between the ridge and a
mid- to upper-level trough over eastern Canada and the northeast
U.S. In general, the models have shifted westward this cycle, and
the NHC track forecast has been nudged in that direction.

Continued moderate to strong westerly vertical wind shear should
limit strengthening during the next 12 to 24 hours. However, more
significant strengthening seems likely in a day or two when the
shear decreases while Franklin remains over warm water and in a
relatively moist environment. Franklin is expected to become a
hurricane over the weekend and should reach a peak intensity near
major hurricane strength early next week. The strengthening trend
should end around day 4, at which time the storm is forecast to
begin moving over cooler waters and into an environment of stronger
shear. The intensity models are in fairly good agreement, and this
forecast is quite similar to the previous one.


FORECAST POSITIONS AND MAX WINDS

INIT 25/0900Z 22.7N 68.0W 50 KT 60 MPH
12H 25/1800Z 22.8N 67.4W 50 KT 60 MPH
24H 26/0600Z 23.3N 66.9W 55 KT 65 MPH
36H 26/1800Z 24.1N 67.0W 60 KT 70 MPH
48H 27/0600Z 25.3N 67.6W 65 KT 75 MPH
60H 27/1800Z 26.9N 68.3W 80 KT 90 MPH
72H 28/0600Z 28.6N 68.8W 90 KT 105 MPH
96H 29/0600Z 33.0N 68.3W 95 KT 110 MPH
120H 30/0600Z 39.2N 63.9W 85 KT 100 MPH

$$
Forecaster Cangialosi

[ScottNAtlanta]

000
WTNT63 KNHC 251310
TCUAT3

Tropical Storm Franklin Tropical Cyclone Update
NWS National Hurricane Center Miami FL AL082023
910 AM AST Fri Aug 25 2023

...FRANKLIN MOVING ERRATICALLY SOUTHEASTWARD...

Satellite and aircraft data indicate that the center of Tropical
Storm Franklin is moving well south of the current NHC track
forecast. A southward adjustment will be made in the short term
track forecast for the upcoming regular advisory to be issued no
later than 1100 AM AST (1500 UTC).


SUMMARY OF 0910 AM AST...1310 UTC...INFORMATION
-----------------------------------------------
LOCATION...21.9N 68.0W
ABOUT 180 MI...190 KM E OF GRAND TURK ISLAND
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...SE OR 125 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES

$$
Forecaster Blake

[cycloneye]

BULLETIN
Tropical Storm Franklin Advisory Number 20
NWS National Hurricane Center Miami FL AL082023
1100 AM AST Fri Aug 25 2023

...FRANKLIN CURRENTLY DISORGANIZED BUT FORECAST TO STRENGTHEN
THIS WEEKEND...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...21.8N 67.8W
ABOUT 215 MI...340 KM E OF GRAND TURK ISLAND
ABOUT 750 MI...1205 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...ESE OR 115 DEGREES AT 5 MPH...7 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES


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



Tropical Storm Franklin Discussion Number 20
NWS National Hurricane Center Miami FL AL082023
1100 AM AST Fri Aug 25 2023

Visible satellite imagery this morning shows that Franklin's
low-level center has become completely exposed, with convection on
the southeastern side of the system due to strong vertical wind
shear. The Air Force Hurricane Hunters have been in the system this
morning and found that the pressure has increased to 1003 mb and
the flight-level winds have decreased, though strong convection
prevented a full sample of the storm. A blend of subjective and
objective satellite estimates are in general agreement with data
from the Air Force reconnaissance that show the winds slightly lower
than the previous advisory. Therefore, the initial intensity is set
to 45 kt.

The storm is moving slowly to the east-southeast at about 4 kt,
around the base of a broad mid- to upper-level trough. A turn to
the east then a northeast motion is expected later today and
tonight as ridging builds to the east of Franklin over the central
Atlantic and the trough drops southwestward. This system will
then turn more northward late this weekend into early next week,
with the core of the system probably moving to the west of Bermuda
on Monday and Tuesday. By the middle of next week, Franklin is
forecast to turn to the northeast and increase in forward motion due
to faster flow between the ridge and a mid-latitude trough over
eastern Canada and the northeast U.S. The NHC track forecast has
shifted southeastward in the short term given the recent motion.
At long range, there was once again another shift to the west in
the guidance envelope and the official track forecast follows the
trend.

Strong westerly vertical wind shear should remain over the system
for the next 24 hours or so, which will probably limit much
strengthening. In a day or two, more significant strengthening is
forecast as the wind shear decreases and Franklin remains over very
warm sea surface temperatures. Franklin is expected to become a
hurricane over the weekend and should reach a peak intensity near
major hurricane strength early next week. The cyclone should
level off in intensity by day 4, followed by a weakening trend
thereafter due to Franklin moving over cooler waters and into a
stronger vertical wind shear environment. The intensity forecast is
fairly similar to the previous, with the only change being a
slightly weaker system in the near term, which lies near the
corrected consensus aids.

FORECAST POSITIONS AND MAX WINDS

INIT 25/1500Z 21.8N 67.8W 45 KT 50 MPH
12H 26/0000Z 22.1N 67.1W 45 KT 50 MPH
24H 26/1200Z 22.8N 66.9W 50 KT 60 MPH
36H 27/0000Z 23.7N 67.5W 55 KT 65 MPH
48H 27/1200Z 25.2N 68.3W 65 KT 75 MPH
60H 28/0000Z 26.8N 69.1W 80 KT 90 MPH
72H 28/1200Z 28.7N 69.4W 95 KT 110 MPH
96H 29/1200Z 33.1N 68.4W 95 KT 110 MPH
120H 30/1200Z 39.0N 63.6W 80 KT 90 MPH

$$
Forecaster Kelly/Blake

NNNN

[cycloneye]

BULLETIN
Tropical Storm Franklin Advisory Number 21
NWS National Hurricane Center Miami FL AL082023
500 PM AST Fri Aug 25 2023

...FRANKLIN TO STRENGTHEN EARLY NEXT WEEK...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...21.9N 67.0W
ABOUT 250 MI...405 KM E OF GRAND TURK ISLAND
ABOUT 735 MI...1180 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 6 MPH...10 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES

Tropical Storm Franklin Discussion Number 21
NWS National Hurricane Center Miami FL AL082023
500 PM AST Fri Aug 25 2023

Franklin's low-level center remains exposed this afternoon on
visible satellite imagery. Strong vertical wind shear continues to
affect the asymmetric system, with the deep convection displaced on
the eastern side of the storm. The Air Force and NOAA Hurricane
Hunters have been in the system much of the day and show that the
flight-level winds and pressure have remained steady. Subjective
Dvorak estimates from TAFB and SAB also remain unchanged from the
previous advisory. Given the data from the Hurricane Hunters and
these satellite estimates, the initial intensity for this advisory
remains at 45 kt.

The storm is moving slowly to the east-northeast at about 5 kt,
around the base of a broad mid- to upper-level trough. This
east-northeast to northeast motion is expected to continue through
tonight as ridging builds to the east of Franklin over the central
Atlantic and the trough drops southwestward. Franklin will then
turn more northward late this weekend into early next week, with the
core of the system probably moving to the west of Bermuda on Monday
and Tuesday. By the middle of next week, Franklin is forecast to
turn to the northeast and accelerate between the ridge and a
mid-latitude trough over eastern Canada and the northeast U.S. The
NHC track forecast has shifted slightly eastward in the short term
given the recent motion. At long range, the guidance envelope and
consensus aids this cycle were to the right of the previous forecast
track. The official NHC forecast was adjusted slightly to the east,
but lies west of the consensus aids for this cycle.

Strong westerly vertical wind shear should remain over Franklin for
the next 24 hours or so, which will probably limit much
strengthening. In a day or two, strengthening is forecast as the
wind shear decreases and Franklin remains over very warm sea surface
temperatures. Franklin is expected to become a hurricane early next
week and should reach a peak intensity near major hurricane strength
by day 4. By the end of the forecast period, a gradual weakening
trend is forecast as Franklin moves over cooler waters and into a
stronger vertical wind shear environment. The intensity guidance was
slightly weaker in the short term, and the official intensity
forecast followed these trends. In the long term, the peak intensity
forecast remains unchanged and near the consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT 25/2100Z 21.9N 67.2W 45 KT 50 MPH
12H 26/0600Z 22.0N 66.5W 45 KT 50 MPH
24H 26/1800Z 22.8N 66.6W 50 KT 60 MPH
36H 27/0600Z 23.8N 66.9W 55 KT 65 MPH
48H 27/1800Z 25.4N 67.7W 60 KT 70 MPH
60H 28/0600Z 27.3N 68.5W 70 KT 80 MPH
72H 28/1800Z 29.2N 68.9W 85 KT 100 MPH
96H 29/1800Z 33.0N 67.7W 95 KT 110 MPH
120H 30/1800Z 37.8N 62.7W 80 KT 90 MPH

$$
Forecaster Kelly/Blake

[cycloneye]

BULLETIN
Tropical Storm Franklin Advisory Number 22
NWS National Hurricane Center Miami FL AL082023
1100 PM AST Fri Aug 25 2023

...FRANKLIN STRENGTHENS...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...22.4N 66.2W
ABOUT 320 MI...515 KM ENE OF GRAND TURK ISLAND
ABOUT 690 MI...1110 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...996 MB...29.42 INCHES


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



Tropical Storm Franklin Discussion Number 22
NWS National Hurricane Center Miami FL AL082023
1100 PM AST Fri Aug 25 2023

Westerly shear continues to affect Franklin tonight, as evidenced by
the sharp edge to its cold cloud tops on infrared satellite images.
However, the low-level center that was exposed earlier today appears
to have moved under the western edge of the convective canopy. An
Air Force Reserve Hurricane Hunter aircraft flew the storm at 700 mb
this evening and reported peak flight-level winds of 56 kt, with
believable SFMR winds in the 45-55 kt range. These data warrant a
slight increase to the initial intensity (50 kt), especially given a
recent dropsonde that suggests the surface pressure has fallen to
996 mb tonight. A recent ASCAT-B pass over Franklin further supports
this, with peak wind vectors slightly above 45 kt. Note that the
initial intensity of Franklin is more uncertain than normal, with
there being a large spread between some of the aircraft data and the
various objective and subjective satellite estimates.

The intense convection closer to the center of Franklin appears to
have drawn the surface center more northeastward, and the initial
motion is an uncertain 60/7 kt. A high pressure ridge building to
the east of Franklin is expected to steer the cyclone more northward
and north-northwestward this weekend and into early next week. Then,
a deep-layer trough is forecast to move across the northeastern U.S.
and eastern Canada by midweek. This should cause Franklin to
accelerate northeastward deeper into the mid latitudes through the
end of the forecast period. The updated NHC track forecast lies to
the east of the previous one during the first 60-72 h of the period,
mainly a result of the eastward adjustment to the initial position
of Franklin. There are some notable forward speed differences beyond
72 h, with the GFS significantly faster than the rest of the global
and regional models. With the NHC forecast remaining near the
multi-model consensus aids, no notable changes were made to this
portion of the track forecast.

The westerly shear that has plagued Franklin for the past couple of
days is expected to decrease during the next 24-36 h. So while only
modest strengthening is forecast in the near term, more significant
strengthening seems likely thereafter as the cyclone moves over
very warm SSTs (29-30 deg C) and within a more favorable dynamic
environment. The updated forecast shows Franklin becoming a
hurricane by 48 h and peaking near major hurricane intensity in
72-96 h, in good agreement with the latest HCCA and IVCN aids. As
Franklin accelerates to higher latitudes, cooler waters and
increased deep-layer shear will induce weakening and eventually
extratropical transition beyond the end of the forecast period.


FORECAST POSITIONS AND MAX WINDS

INIT 26/0300Z 22.4N 66.2W 50 KT 60 MPH
12H 26/1200Z 23.0N 66.0W 55 KT 65 MPH
24H 27/0000Z 23.9N 66.3W 55 KT 65 MPH
36H 27/1200Z 25.3N 67.0W 60 KT 70 MPH
48H 28/0000Z 27.0N 67.9W 70 KT 80 MPH
60H 28/1200Z 28.8N 68.4W 80 KT 90 MPH
72H 29/0000Z 30.5N 68.4W 95 KT 110 MPH
96H 30/0000Z 34.7N 66.5W 95 KT 110 MPH
120H 31/0000Z 40.0N 60.0W 75 KT 85 MPH

$$
Forecaster Reinhart

[abajan]

BULLETIN
Tropical Storm Franklin Advisory Number 23
NWS National Hurricane Center Miami FL AL082023
500 AM AST Sat Aug 26 2023

...FRANKLIN SLOWLY STRENGTHENING...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...22.8N 65.8W
ABOUT 350 MI...565 KM ENE OF GRAND TURK ISLAND
ABOUT 660 MI...1060 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...992 MB...29.30 INCHES


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



Tropical Storm Franklin Discussion Number 23
NWS National Hurricane Center Miami FL AL082023
500 AM AST Sat Aug 26 2023

Franklin is gradually getting better organized. During the past
couple of days, deep convection has been mainly confined to the east
of the center. However, there has been a change recently with the
convective pattern becoming a little more symmetric, likely due to a
decrease in vertical wind shear. The Dvorak classifications from
TAFB and SAB have increased to 3.5/55 kt, and the initial intensity
is raised to that value.

The storm is still moving east-northeastward at 6 kt, but a sharp
northward turn is expected to occur later today as a ridge builds to
the east of the system over the central Atlantic. A northward to
north-northwestward motion is forecast during the next few days as
the storm moves along the western periphery of the ridge, taking it
to the west of Bermuda on Tuesday. By the middle of next week, a
faster northeastward motion is expected when Franklin moves in the
flow between the ridge and a mid- to upper-level trough over eastern
Canada and the northeastern U.S. The track models have shifted to
the west this cycle, and the NHC track forecast follows that theme
and is a little slower than the previous one at days 4 and 5.

Franklin is expected to steadily strengthen during the next few days
as the vertical wind shear becomes light while the storm remains
over warm water and in a relatively moist environment. Franklin
will likely become a hurricane by tonight and possibly a major
hurricane early next week. The strengthening trend should end in 3
to 4 days when the shear is expected to increase and weakening
should commence in 4 to 5 days when Franklin is forecast to move
over much cooler waters. The intensity models are higher this
cycle, and the NHC forecast has been nudged upward, close to the
IVCN and HCCA models.


FORECAST POSITIONS AND MAX WINDS

INIT 26/0900Z 22.8N 65.8W 55 KT 65 MPH
12H 26/1800Z 23.4N 66.0W 60 KT 70 MPH
24H 27/0600Z 24.6N 66.6W 70 KT 80 MPH
36H 27/1800Z 26.0N 67.7W 80 KT 90 MPH
48H 28/0600Z 27.5N 68.6W 90 KT 105 MPH
60H 28/1800Z 29.3N 68.8W 95 KT 110 MPH
72H 29/0600Z 31.0N 68.7W 100 KT 115 MPH
96H 30/0600Z 34.8N 66.2W 90 KT 105 MPH
120H 31/0600Z 39.9N 58.1W 75 KT 85 MPH

$$
Forecaster Cangialosi

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 24
NWS National Hurricane Center Miami FL AL082023
1100 AM AST Sat Aug 26 2023

...FRANKLIN STRENGTHENS INTO A HURRICANE...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...23.5N 66.7W
ABOUT 315 MI...505 KM ENE OF GRAND TURK ISLAND
ABOUT 620 MI...995 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...NNW OR 345 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...989 MB...29.21 INCHES


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


Hurricane Franklin Discussion Number 24
NWS National Hurricane Center Miami FL AL082023
1100 AM AST Sat Aug 26 2023

Franklin has become better organized this morning on satellite and
microwave imagery. An earlier SSMIS microwave pass showed a
developing core with the mid and low-level center becoming more
vertically aligned. Early visible satellite images showed a ragged
eye, which has become cloud filled in the last hour or two. Deep
convection around Franklin has become more symmetric compared to
recent days, likely due to a decrease in vertical wind shear. Air
Force and NOAA Hurricane Hunters have been in the system
this morning, and found that the surface pressure has dropped to
989 mb and SFMR winds were around 60 to 65 kt from both aircraft.
Given the data from the aircraft reconnaissance, Franklin has been
upgraded to a Hurricane, with the initial intensity set at 65 kt.
Franklin is the second hurricane of the 2023 Atlantic hurricane
season.

Franklin is moving north-northwestward at 6 kt. A
north-northwestward to northward motion is forecast during the next
few days as the storm moves along the western periphery of a
mid-level ridge, taking it to the west of Bermuda on Tuesday. By
the middle of next week, a faster northeastward motion is expected
when Franklin moves in between the ridge and a mid- to upper-level
trough over eastern Canada and the northeastern United States. The
track models have shifted to the west once again this cycle, and the
NHC track forecast follows that trend and is slightly slower than
the previous one at long ranges.

Franklin is expected to steadily strengthen during the next few days
with lower vertical wind shear, and warm sea surface temperatures in
the western Atlantic. Franklin is forecast to become a major
hurricane early next week. The strengthening trend should end in
about 3 to 4 days with shear expected to increase. By Day 5, the
system will move over much cooler SSTs leading to increased
weakening. The intensity models are higher this cycle, and the NHC
forecast has been nudged upward, but still remains below the IVCN
and HCCA consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT 26/1500Z 23.5N 66.7W 65 KT 75 MPH
12H 27/0000Z 24.2N 67.0W 70 KT 80 MPH
24H 27/1200Z 25.4N 67.8W 80 KT 90 MPH
36H 28/0000Z 27.0N 68.8W 90 KT 105 MPH
48H 28/1200Z 28.5N 69.4W 100 KT 115 MPH
60H 29/0000Z 30.2N 69.5W 105 KT 120 MPH
72H 29/1200Z 31.9N 69.0W 105 KT 120 MPH
96H 30/1200Z 35.6N 65.9W 90 KT 105 MPH
120H 31/1200Z 40.5N 56.9W 75 KT 85 MPH

$$
Forecaster Kelly/Pasch

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 25
NWS National Hurricane Center Miami FL AL082023
500 PM AST Sat Aug 26 2023

...FRANKLIN CONTINUES TO STRENGTHEN...
...FORECAST TO BECOME A MAJOR HURRICANE EARLY NEXT WEEK...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...23.8N 67.5W
ABOUT 280 MI...450 KM NE OF GRAND TURK ISLAND
ABOUT 610 MI...980 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...982 MB...29.00 INCHES


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


Hurricane Franklin Discussion Number 25
NWS National Hurricane Center Miami FL AL082023
500 PM AST Sat Aug 26 2023


Visible and microwave satellite imagery show Franklin is becoming a
well organized hurricane. AMSR2 microwave data showed a closed
mid-level core that was vertically aligned with the low-level
center. The latest visible imagery shows a dimple where an eye may
be trying to develop. Deep convection has become more symmetrical,
wrapping around the center throughout the day. NOAA Hurricane
Hunters were in the system earlier this afternoon, with flight-level
winds and SFMR winds supporting an intensity of around 70 kt. The
UW-CIMSS ADT objective satellite estimates have been rising this
afternoon as well. Given the improved satellite structure combined
with the earlier data from the NOAA Hurricane Hunters, the initial
intensity is raised to 75 kt for this advisory. NOAA and Air Force
Hurricane Hunters will be in the system later this evening.

Franklin is moving north-northwestward at 7 kt. A
north-northwestward to northward motion is forecast during the next
few days as the storm moves along the western periphery of a
mid-level ridge, taking it to the west of Bermuda on Tuesday. By
the middle of next week, a faster northeast to east-northeast motion
is expected between the ridge and a mid- to upper-level trough over
eastern Canada and the northeastern United States. In the short
range, models once again have trended westward, and the official NHC
forecast has been nudged west as well. For the long term, models,
including the GFS and ECMWF, have made a fairly large shift to the
right. The NHC track was shifted in that direction in the long term,
but remains to the left of the consensus aids. The confidence of the
long-term forecast track is lower than usual.

Franklin has been steadily strengthening throughout the day. Further
strengthening is forecast during the next few days with lower
vertical wind shear and warm sea surface temperatures in the western
Atlantic. Franklin is forecast to become a major hurricane early
next week. The strengthening trend should end in about 3 to 4 days
with shear expected to increase over the system at that time. By day
5, the current forecast track takes the system over much cooler
SSTs. However, the intensity in the long range will be dependent on
the eventual forecast track of Franklin. The current intensity
forecast lies near the consensus aids, but still slightly lower than
the HCCA aid.


FORECAST POSITIONS AND MAX WINDS

INIT 26/2100Z 23.8N 67.5W 75 KT 85 MPH
12H 27/0600Z 24.7N 68.1W 85 KT 100 MPH
24H 27/1800Z 25.9N 68.9W 95 KT 110 MPH
36H 28/0600Z 27.1N 69.6W 105 KT 120 MPH
48H 28/1800Z 28.7N 69.9W 110 KT 125 MPH
60H 29/0600Z 30.3N 69.9W 110 KT 125 MPH
72H 29/1800Z 32.0N 69.4W 105 KT 120 MPH
96H 30/1800Z 35.2N 65.6W 90 KT 105 MPH
120H 31/1800Z 39.1N 56.5W 75 KT 85 MPH

$$
Forecaster Kelly/Pasch

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 26
NWS National Hurricane Center Miami FL AL082023
1100 PM AST Sat Aug 26 2023

...FRANKLIN FORECAST TO BECOME A MAJOR HURRICANE BY LATE SUNDAY...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...23.9N 68.2W
ABOUT 250 MI...400 KM NE OF GRAND TURK ISLAND
ABOUT 615 MI...990 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...975 MB...28.80 INCHES


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


Hurricane Franklin Discussion Number 26
NWS National Hurricane Center Miami FL AL082023
1100 PM AST Sat Aug 26 2023

The eye of Franklin has been obscured in conventional satellite
imagery by deep convective bursts within its southern eyewall during
the past several hours. At times, there has been some disruption of
the inner core convection by drier air wrapping around the eastern
and northern portions of the circulation. Both the Air Force and
NOAA Hurricane Hunters investigated Franklin tonight and provided
useful data to analyze the storm. Tail Doppler radar data from the
NOAA aircraft reveal better vertical alignment of Franklin's vortex,
although there is still a bit of tilt with height. Peak SFMR wind
retrievals from both aircraft support an initial intensity of 75 kt,
and the latest dropsonde data indicate the surface pressure has
fallen to 975 mb.

Conditions appear favorable for some significant strengthening of
Franklin during the next couple of days. The deep-layer shear is
forecast to continue decreasing over the cyclone while it traverses
very warm SSTs greater than 29 deg C. The hurricane could be prone
to more rapid fluctuations in intensity given its small inner core,
and some of the rapid intensification (RI) guidance, particularly
DTOPS, suggests there are well above average chances that Franklin
could undergo RI during the next 48 h. Thus, the updated intensity
forecast is raised in the near term, bringing Franklin to major
hurricane strength in 24 h with a peak intensity of 115 kt on
Monday. This lies near HCCA and IVCN, but below some of the regional
hurricane models (HAFS and COAMPS-TC). Weakening is forecast at
days 4 and 5 as Franklin encounters increased shear over cooler
SSTs, but its wind field is expected to grow as it moves deeper into
the mid-latitudes.

The aircraft fixes indicate Franklin has continued to deviate left
of the forecast track, and its initial motion is northwestward at 7
kt. The near-term track forecast has been adjusted west of the
previous one based on Franklin's continued northwestward motion. A
broad high pressure ridge to the east of Franklin should steer the
hurricane more north-northwestward and northward during the next
couple of days. Later in the period, a deep-layer trough is expected
to move off the U.S. east coast, and most global models (except the
ECMWF) show Franklin becoming captured within the southwesterly flow
ahead of the trough and accelerating northeastward. The NHC forecast
track still shows the core of Franklin passing west and north of
Bermuda, but interests there should continue to monitor the latest
NHC forecast updates. By day 5, interaction with the upper trough
could bring about the start of extratropical transition.


FORECAST POSITIONS AND MAX WINDS

INIT 27/0300Z 23.9N 68.2W 75 KT 85 MPH
12H 27/1200Z 24.9N 68.9W 85 KT 100 MPH
24H 28/0000Z 26.2N 69.8W 100 KT 115 MPH
36H 28/1200Z 27.6N 70.4W 110 KT 125 MPH
48H 29/0000Z 29.2N 70.4W 115 KT 130 MPH
60H 29/1200Z 30.8N 69.9W 115 KT 130 MPH
72H 30/0000Z 32.5N 68.9W 105 KT 120 MPH
96H 31/0000Z 35.8N 63.7W 90 KT 105 MPH
120H 01/0000Z 41.0N 52.5W 75 KT 85 MPH

$$
Forecaster Reinhart

[Extratropical94]

BULLETIN
Hurricane Franklin Advisory Number 27
NWS National Hurricane Center Miami FL AL082023
500 AM AST Sun Aug 27 2023

...FRANKLIN FORECAST TO RAPIDLY INTENSIFY INTO A MAJOR HURRICANE...
...INTERESTS IN BERMUDA SHOULD MONITOR THE PROGRESS OF FRANKLIN...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...24.7N 68.7W
ABOUT 270 MI...430 KM NE OF GRAND TURK ISLAND
ABOUT 575 MI...925 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H
PRESENT MOVEMENT...NW OR 320 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...973 MB...28.74 INCHES


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

Interests in Bermuda should monitor the progress of this system.


Hurricane Franklin Discussion Number 27
NWS National Hurricane Center Miami FL AL082023
500 AM AST Sun Aug 27 2023

After becoming obscured for a time earlier tonight, the eye of
Franklin is beginning to re-emerge on infrared satellite images
early this morning. The last helpful microwave pass at 0246 UTC
showed some disruption of Franklin's inner core that could have
been due to southerly shear causing the eyewall to be open to the
east. This structure was also observed by both NOAA and Air Force
Reconnaissance missions earlier tonight. Intensity estimates from
SAB and TAFB were both T4.5/77 kt this morning, but with the recent
re-emergence of the eye, the advisory intensity is bumped up to 80
kt for this advisory.

Franklin is moving to the northwest this morning with an estimated
motion of 320/7 kt. The track forecast over the next 48 h is
relatively straightforward as the cyclone is expected to round the
western side of a mid-level subtropical ridge to its east. The
track guidance over this time span is in good agreement, and the
latest NHC track forecast is very close to or just a bit west of
the prior one through 48 h. Afterwards, uncertainty quickly
increases, primarily related to whether Franklin will be captured
by a mid-latitude trough emerging off the eastern US coastline.
While the GFS continues to show the hurricane being captured by
this trough, the latest runs of the ECMWF, CMC, and UKMET now leave
the cyclone behind, resulting in it turning more eastward and
slowing down as the trough bypasses it to its north. Both the
ECMWF and GFS ensembles show a huge amount of spread, spanning more
than 1000 mi at the end of the forecast period. While the latest
NHC track forecast will not shift all the way to Franklin being
left behind by the trough, it is noticeably slower and eastward
compared to the prior track at days 4 and 5. Future adjustments to
the southeast may become necessary in subsequent cycles. On the
forecast track, Franklin will be making its closest approach to
Bermuda in 3-4 days, and is a bit closer to Bermuda than the prior
advisory.

As long as the small eyewall observed by earlier recon and microwave
imagery is closing back off, Franklin should continue to intensify,
likely rapidly due to favorable low shear and ample warm waters
under the hurricane. DTOPS continues to suggest between a 59-68
percent chance of a 30 kt intensity increase in the next 24 hours,
and the latest intensity forecast is close to this scenario, taking
the storm to a category 3 hurricane in 24 hours and peaking it as a
115-kt category 4 hurricane in 36 hours. This is near the higher
end of the intensity guidance, but is quite close to the latest
HFIP corrected consensus forecast. Afterwards, there are a couple
of factors that could cause Franklin to start weakening. First, the
storm will likely undergo fluctuations related to eyewall
replacement cycles, which would also broaden its overall wind
field. In addition, the motion of Franklin is relatively slow, and
the warm 29-30 C waters it will be traversing are fairly shallow,
leaving the cyclone prone to cool upwelling along its track as the
wind field expands. Vertical wind shear out of the northwest also
increases after 36 hours. All of these factors are why the latest
NHC intensity forecast shows weakening beginning after this period,
which is also in good agreement with both the simple and corrected
consensus aids. Given the large spread of solutions at days 4 and 5,
it is unclear if Franklin will start to undergo extratropical
transition during that time, or will be left behind by the trough,
resulting in a slower motion that stays over warmer waters
south of the Gulf Stream.


FORECAST POSITIONS AND MAX WINDS

INIT 27/0900Z 24.7N 68.7W 80 KT 90 MPH
12H 27/1800Z 25.6N 69.4W 90 KT 105 MPH
24H 28/0600Z 26.9N 70.3W 105 KT 120 MPH
36H 28/1800Z 28.4N 70.6W 115 KT 130 MPH
48H 29/0600Z 29.9N 70.4W 110 KT 125 MPH
60H 29/1800Z 31.3N 69.5W 100 KT 115 MPH
72H 30/0600Z 33.0N 67.9W 90 KT 105 MPH
96H 31/0600Z 36.5N 61.0W 80 KT 90 MPH
120H 01/0600Z 40.0N 52.0W 70 KT 80 MPH

$$
Forecaster Papin

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 28
NWS National Hurricane Center Miami FL AL082023
1100 AM AST Sun Aug 27 2023

...AIR FORCE HURRICANE HUNTERS FIND FRANKLIN A LITTLE STRONGER...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...25.1N 69.3W
ABOUT 275 MI...445 KM NNE OF GRAND TURK ISLAND
ABOUT 565 MI...905 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...971 MB...28.68 INCHES


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

Interests in Bermuda should monitor the progress of this system.


Hurricane Franklin Discussion Number 28
NWS National Hurricane Center Miami FL AL082023
1100 AM AST Sun Aug 27 2023

Air Force Hurricane Hunters have been investigating Franklin this
morning and found Franklin a little stronger, with the pressure down
a few millibars to 971mb. Latest visible and infrared satellite
imagery show an eye developing with a cold core of deep convection
wrapping around the center. The aircraft reconnaissance reported
that the eye was closed in the most recent vortex fix. They also
reported a concentric band forming around the eyewall, which may be
the stages of an eyewall replacement cycle. Satellite estimates from
TAFB and SAB, remained steady this advisory. However, given the
improved satellite depiction in the last few hours and data from
the hurricane hunters, the initial intensity is raised to 85kt.

Environmental conditions are fairly favorable during the next few
days, with very warm sea surface temperature and decreasing
deep-layer wind shear. Steady strengthening is forecast and
Franklin could become a major hurricane later tonight or tomorrow.
The intensity forecast remains similar to the previous one and
lies near the consensus aids, HCCA and IVCN. Weakening is forecast
in about 3 to 4 days, as Franklin encounters increased shear and
moves over cooler SSTs. The wind field of Franklin is forecast to
increase in size as it moves into the mid-latitudes.

Franklin has continued to move northwestward at 7kt this morning.
The near-term forecast has been nudged slightly west of the
previous advisory. A broad high-pressure ridge to the east of
Franklin will steer the system more north-northwestward and
northward the next couple of days. In the longer range of the
forecast period, a deep trough is expected to move off the U.S.
east coast and most of the guidance has Franklin becoming
captured in the southwesterly flow, with an increase in forward
motion to the northeast. The main exception is the ECMWF, which is
the furthest right once again this forecast cycle. The official
forecast track lies near the model consensus aids, in the middle of
the guidance suite. The NHC forecast track still has the core of
Franklin passing west and north of Bermuda, but interest there
should continue to monitor the latest NHC forecast. By Day 5 or
just beyond the forecast period, Franklin may begin to interact
with the upper trough and begin an extratropical transition.



FORECAST POSITIONS AND MAX WINDS

INIT 27/1500Z 25.1N 69.2W 85 KT 100 MPH
12H 28/0000Z 26.0N 70.0W 95 KT 110 MPH
24H 28/1200Z 27.4N 70.7W 105 KT 120 MPH
36H 29/0000Z 28.9N 70.8W 115 KT 130 MPH
48H 29/1200Z 30.4N 70.4W 110 KT 125 MPH
60H 30/0000Z 31.9N 69.2W 105 KT 120 MPH
72H 30/1200Z 33.4N 67.0W 95 KT 110 MPH
96H 31/1200Z 36.6N 60.1W 85 KT 100 MPH
120H 01/1200Z 40.6N 52.5W 65 KT 75 MPH

$$
Forecaster Kelly/Pasch

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 29
NWS National Hurricane Center Miami FL AL082023
500 PM AST Sun Aug 27 2023

...FRANKLIN FORECAST TO BECOME A MAJOR HURRICANE ON MONDAY...
...LIFE THREATENING SURF AND RIP CURRENTS POSSIBLE ALONG THE EAST
COAST OF THE UNITED STATES...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...25.9N 70.0W
ABOUT 320 MI...515 KM NNE OF GRAND TURK ISLAND
ABOUT 535 MI...855 KM SW OF BERMUDA
MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...970 MB...28.65 INCHES


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

Interests in Bermuda should monitor the progress of this system.


Hurricane Franklin Discussion Number 29
NWS National Hurricane Center Miami FL AL082023
500 PM AST Sun Aug 27 2023

Visible and infrared satellite imagery has improved slightly since
this morning, with a tight inner core developing around the center.
There have been hints of an eye developing in infrared and visible
images throughout the day, but the eye remains cloud filled.
Franklin is still dealing with a little bit of drier mid-level dry
air trying to wrap into the eastern side. Subjective and objective
Dvorak estimates have remained steady throughout the day today. With
these estimates combined with the lower surface pressure reported by
the aircraft, the initial intensity remains at 85 kt this advisory.
The Air Force Hurricane Hunters will be investigating the system
later this evening.

Environmental conditions are fairly favorable for the next few days,
with very warm sea surface temperatures and vertical wind shear
forecast to decrease. Steady to rapid strengthening is forecast, and
Franklin could become a major hurricane on Monday. In about 3 to 4
days, weakening is forecast as Franklin encounters increased shear
and moves over cooler SSTs. The wind field of Franklin is forecast
to increase in size as it moves into the mid-latitudes.

Franklin is moving northwestward at 8 kt, around a broad
high-pressure ridge to the east of Franklin. This ridge will steer
the system more north-northwestward and northward over the next
couple of days. In the longer range of the forecast period, a deep
trough is expected to move off the U.S. east coast, and most of the
guidance has Franklin becoming captured in the southwesterly flow,
with an increase in forward motion to the northeast. The official
NHC forecast track lies near the model consensus aids, with only
slight adjustments to the previous advisory. The NHC forecast track
still has the core of Franklin passing west and north of Bermuda,
but interests there should continue to monitor the latest NHC
forecasts. By day 5, Franklin may begin to interact with the upper
trough and begin an extratropical transition, although that is not
explicitly forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 27/2100Z 25.9N 70.0W 85 KT 100 MPH
12H 28/0600Z 27.0N 70.6W 95 KT 110 MPH
24H 28/1800Z 28.5N 71.0W 105 KT 120 MPH
36H 29/0600Z 30.0N 70.9W 115 KT 130 MPH
48H 29/1800Z 31.5N 69.9W 115 KT 130 MPH
60H 30/0600Z 33.2N 68.2W 105 KT 120 MPH
72H 30/1800Z 34.5N 65.4W 100 KT 115 MPH
96H 31/1800Z 37.1N 58.4W 85 KT 100 MPH
120H 01/1800Z 41.0N 50.8W 70 KT 80 MPH

$$
Forecaster Kelly/Pasch

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 30
NWS National Hurricane Center Miami FL AL082023
1100 PM EDT Sun Aug 27 2023

...FRANKLIN IS STRENGTHENING...
...SWELLS LIKELY TO PRODUCE LIFE-THREATENING SURF AND RIP CURRENTS
ALONG THE EAST COAST OF THE UNITED STATES EARLY THIS WEEK...


SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...26.4N 70.5W
ABOUT 340 MI...550 KM N OF GRAND TURK ISLAND
ABOUT 530 MI...855 KM SW OF BERMUDA
MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...962 MB...28.41 INCHES


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

Interests in Bermuda should monitor the progress of this system.
Watches will likely be required for Bermuda on Monday.



Hurricane Franklin Discussion Number 30
NWS National Hurricane Center Miami FL AL082023
1100 PM EDT Sun Aug 27 2023

Franklin is becoming better organized tonight. A ragged eye has
emerged in conventional satellite imagery during the past few hours,
and the Air Force Hurricane Hunters reported a closed eyewall during
recent passes through the center. Aircraft data indicated the
minimum pressure has continued to fall, with a 00 UTC dropsonde
reporting a pressure of 964 mb. Since the plane departed, the
satellite structure of Franklin has markedly improved, with very
cold cloud tops wrapping around the eastern portion of the
circulation. The initial intensity of 90 kt is supported by recent
objective estimates from UW-CIMSS and a T5.0 subjective Dvorak
classification from TAFB at 00 UTC.

Recent satellite images suggest the hurricane is finally turning
more northward as expected, and the initial motion is
north-northwestward (330/7 kt). A gradual turn to the north and
north-northeast is forecast during the next couple of days as
Franklin moves around the western periphery of a high pressure
ridge. The track guidance is in good agreement on this portion of
the forecast, and only minor westward adjustments were made
following the latest HCCA and TVCA aids. Thereafter, track
uncertainty increases regarding Franklin's interaction with a
deep-layer trough moving off the U.S. east coast by midweek. The GFS
and ECMWF lie on opposite sides of the guidance envelope, with an
850 n-mi spread at 96 h. Given the greater than normal uncertainty,
the NHC track forecast remains close to the multi-model consensus
aids at days 3-5, showing a gradually faster east-northeastward to
northeastward motion during this period.

Based on recent satellite trends, it appears that the shear has
weakened and the inner core of Franklin has become more solidified.
Thus, the hurricane could be primed to strengthen in the near term
within a low shear environment over very warm SSTs. The NHC forecast
brings Franklin to major hurricane intensity in 12 h with more
strengthening thereafter, in best agreement with some of the
regional hurricane models and slightly above the HCCA/IVCN aids. As
the hurricane recurves, increased deep-layer shear and cooler waters
should induce some weakening, although the wind field will expand
while the hurricane moves further into the mid-latitudes. This
forecast shows Franklin becoming extratropical at day 5, although
the timing could be refined based on future track forecasts.

Although the core of Franklin is forecast to pass west and north of
Bermuda during the next few days, its expanding wind field will
likely require a tropical storm watch for the island on Monday.


FORECAST POSITIONS AND MAX WINDS

INIT 28/0300Z 26.4N 70.5W 90 KT 105 MPH
12H 28/1200Z 27.3N 71.0W 100 KT 115 MPH
24H 29/0000Z 28.9N 71.2W 110 KT 125 MPH
36H 29/1200Z 30.4N 70.7W 115 KT 130 MPH
48H 30/0000Z 32.2N 69.5W 110 KT 125 MPH
60H 30/1200Z 33.8N 67.3W 100 KT 115 MPH
72H 31/0000Z 35.2N 64.2W 95 KT 110 MPH
96H 01/0000Z 37.5N 57.0W 80 KT 90 MPH
120H 02/0000Z 42.0N 49.5W 65 KT 75 MPH...POST-TROP/EXTRATROP

$$
Forecaster Reinhart

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 31
NWS National Hurricane Center Miami FL AL082023
500 AM EDT Mon Aug 28 2023

...FRANKLIN BECOMES THE FIRST MAJOR HURRICANE OF THE 2023
ATLANTIC HURRICANE SEASON...


SUMMARY OF 500 AM EDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...27.2N 70.8W
ABOUT 395 MI...635 KM N OF GRAND TURK ISLAND
ABOUT 505 MI...810 KM SW OF BERMUDA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...NNW OR 335 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...956 MB...28.23 INCHES


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

Interests in Bermuda should monitor the progress of this system.
Watches will likely be required for Bermuda later today.


Hurricane Franklin Discussion Number 31
NWS National Hurricane Center Miami FL AL082023
500 AM EDT Mon Aug 28 2023

Franklin has continued to improve in organization during the
overnight hours. The eye noted in the previous advisory has
occasionally cleared out on infrared satellite imagery, with the
cold eyewall temperatures surrounding it cooling to between -65 to
-75 C in a thick region around the center. Subjective Dvorak
classifications were both T5.5/102 kt from TAFB and SAB, while
UW-CIMSS ADT estimates are now as high as T5.7/107 kt. The initial
intensity was raised to 100 kt at 06 UTC, and that will remain the
intensity at 09 UTC. While this may be slightly conservative,
earlier aircraft data showed that the maximum winds were lagging the
satellite presentation and minimum pressure of the hurricane. This
intensity still makes Franklin the first major hurricane of the 2023
Atlantic hurricane season. Another Air Force Reconnaissance mission
will be in the hurricane this morning to provide an updated
assessment of the storm.

The hurricane continues to make a gradual turn northward, with the
latest motion estimate still north-northwest at 335/7 kt. Over the
next 48 hours the hurricane should continue to turn northward and
then north-eastward as it rounds the western periphery of a
subtropical ridge, and very little change was made to the NHC track
over this time period. After 48 hours, there continues to be
significant spread, especially in the along-track direction, related
to how much a mid-latitude trough ejecting out of Canada is able to
capture the hurricane. The big change this forecast cycle is that
the ECMWF has come on board showing a trough capture, though it
still remains slower than the majority of the guidance suite. The
latest NHC track forecast has thus been adjusted a bit north and is
quite a bit faster after 48 hours, but is not quite as fast as the
TCVN and HCCA consensus aids over this period.

Some additional intensification is anticipated today, as Franklin
remains in a low shear environment and is over warm 29-30 C
sea-surface temperatures. The latest intensity forecast still peaks
Franklin as a Category 4 (115-kt) major hurricane. However,
inner-core changes, such as eyewall replacement cycles, could occur
at any time, making it somewhat tricky to pinpoint exactly when
Franklin will reach peak intensity. After 24 hours, the broadening
wind field and relatively slow storm motion could make the hurricane
prone to some local upwelling. In addition, some northwesterly
shear may also begin to affect the storm. Toward the end of the
forecast period, more dramatic weakening is possible as the storm
gets swept up in the mid-latitudes. The latest forecast shows the
storm becoming a post-tropical extratropical cyclone in 120 h,
though this could occur sooner than forecasted if the faster
solutions, like the GFS, pan out.

The current forecast shows the core of Franklin passing west and
north of Bermuda in about 60 h, but a tropical storm watch may still
become necessary later today as its expanding 34-kt wind field to
the southeast does get close to the island after 48 hours.

FORECAST POSITIONS AND MAX WINDS

INIT 28/0900Z 27.2N 70.8W 100 KT 115 MPH
12H 28/1800Z 28.3N 71.1W 110 KT 125 MPH
24H 29/0600Z 29.8N 71.0W 115 KT 130 MPH
36H 29/1800Z 31.6N 70.2W 105 KT 120 MPH
48H 30/0600Z 33.2N 68.6W 95 KT 110 MPH
60H 30/1800Z 35.0N 65.7W 90 KT 105 MPH
72H 31/0600Z 37.0N 62.0W 85 KT 100 MPH
96H 01/0600Z 42.0N 53.0W 75 KT 85 MPH
120H 02/0600Z 48.0N 44.0W 65 KT 75 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin

[Teban54]

800
WTNT63 KNHC 281135
TCUAT3

Hurricane Franklin Tropical Cyclone Update
NWS National Hurricane Center Miami FL AL082023
735 AM EDT Mon Aug 28 2023

...AIR FORCE HURRICANE HUNTERS FIND FRANKLIN TO BE STRONGER...

Air Force Reserve Hurricane Hunter aircraft data indicate that
Hurricane Franklin has strengthened this morning. The maximum winds
are estimated to be 130 mph (210 km/h) with higher gusts. The
minimum central pressure has dropped to 942 mb. The next full
advisory on Franklin will be at 11AM EDT (1500 UTC).

SUMMARY OF 735 AM...1135 UTC...INFORMATION
----------------------------------------------
LOCATION...27.4N 70.8W
ABOUT 405 MI...650 KM N OF GRAND TURK ISLAND
ABOUT 490 MI...790 KM SW OF BERMUDA
MAXIMUM SUSTAINED WINDS...130 MPH...210 KM/H
PRESENT MOVEMENT...NNW OR 335 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...942 MB...27.82 INCHES

$$
Forecaster Kelly/Brown

[cycloneye]

Hurricane Franklin Tropical Cyclone Update
NWS National Hurricane Center Miami FL AL082023
900 AM EDT Mon Aug 28 2023

...FRANKLIN RAPIDLY INTENSIFYING...

Air Force Reserve Hurricane Hunter aircraft data indicate that
Hurricane Franklin is rapidly intensifying. The maximum winds are
estimated to be 145 mph (230 km/h) with higher gusts. The minimum
central pressure has decreased to 937 mb. The next full advisory on
Franklin will be at 11AM EDT (1500 UTC), and the intensity forecast
at that time will be increased from the previous advisory given the
ongoing rapid intensification.

SUMMARY OF 0900 AM...1300 UTC...INFORMATION
----------------------------------------------
LOCATION...27.5N 70.9W
ABOUT 410 MI...660 KM N OF GRAND TURK ISLAND
ABOUT 485 MI...780 KM SW OF BERMUDA
MAXIMUM SUSTAINED WINDS...145 MPH...230 KM/H
PRESENT MOVEMENT...NNW OR 335 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...937 MB...27.67 INCHES

$$
Forecaster Kelly/Brown