[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011803
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Fri Sep 1 2023

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through
1755 UTC.

...SPECIAL FEATURES...

Post-Tropical Cyclone Idalia is centered near 31.7N 67.W at
01/1800 UTC or 135 nm WSW of Bermuda, moving ESE at 15 kt.
Estimated minimum central pressure is 1000 mb. Maximum sustained
wind speed is 45 kt with gusts to 55 kt. A gale warning is in
effect through early Sun, with gale force winds occurring N of 29N
between 60W and 75W. Fresh to strong winds are evident north of
27N and between 62W and 75W. Seas are peaking around 21 ft near
the center, with the 12 ft seas extending N of 29N between 58W and
75W. A cold front extends from Idalia to the south and a surface
trough continues to the NW Bahamas, causing scattered moderate
convection within 90 nm to the south of these boundaries. A
general ESE trajectory at a slower forward speed is expected
through Saturday. A turn toward the east and then northeast is
forecast late Saturday and Sunday. On the forecast track, the
center of Idalia will move near or to the south of Bermuda on
Saturday. Additional weakening is forecast through early Saturday.
Restrengthening is possible over the weekend, and Idalia could
transition back to a tropical storm on Saturday. Swells generated
by Idalia will continue to affect the southeastern U.S. coast
during the next couple of days and will reach Bermuda today. These
swells are likely to cause life- threatening surf and rip current
conditions. Please consult products from your local weather
office.

Hurricane Franklin is centered near 38.7N 55.6W at 01/1500 UTC
or 590 nm NE of Bermuda, moving NE at 16 kt. Estimated minimum
central pressure is 985 mb. Maximum sustained wind speed is 65
kt with gusts to 80 kt. Seas are peaking around 30 ft near the
center. A faster northeastward motion is expected during the next
day or so, followed by a northeastward to east-northeastward
motion into early next week. Some fluctuations in intensity are
possible during the next day or so, followed by weakening through
early next week. Franklin is forecast to become an extratropical
cyclone by tonight.

Tropical Storm Jose is centered near 36.0N 50.9W at 01/1500 UTC
or 730 nm ENE of Bermuda, moving NNE at 20 kt. Estimated minimum
central pressure is 999 mb. Maximum sustained wind speed is 45
kt with gusts to 55 kt. Seas are peaking around 14 ft near the
center. Jose is rather small in size and most of the convection
is sheared to the south. A general motion to the NNE with an
increase in forward speed is expected through early Saturday.
Little change in strength is forecast, and Jose is expected to
become absorbed by Franklin tonight or early Saturday.

Tropical Depression Gert is centered near 28.7N 54.6W at 01/1500
UTC or 570 nm ESE of Bermuda, moving E at 6 kt. Estimated
minimum central pressure is 1008 mb. Maximum sustained wind
speed is 30 kt with gusts to 40 kt. Seas are peaking to 9 ft near
the center. Scattered moderate convection is noted from 25N to
29N and between 52W to 58W. The current eastward motion of TD Gert
is forecast to continue today. A turn toward the northeast is
expected over the weekend. Gert could become a tropical storm
later today. The system is forecast to become post-tropical or
dissipate by the end of the weekend.

Newly formed Tropical Depression Twelve is centered near 19.6N 28.3W at
01/1500 UTC or 330 nm NW of the Cabo Verde Islands, moving NNW
at 7 kt. Estimated minimum central pressure is 1007 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. Seas near the
center around 10 ft. Scattered moderate to isolated strong convection
is seen from 16N and 24N and between 25W and 29W. Fresh to strong
winds are found north of the circulation to 28N and between 23W
and 32W, along with seas of 4-8 ft. A motion toward the north-
northwest and northwest at a faster forward speed is expected
through Sunday. A turn toward the west- northwest is forecast
later on Sunday. Some strengthening is expected, and the
depression is forecast to become a tropical storm later today or
this evening. The system is likely to weaken early Sunday and
degenerate to a remnant low by late Sunday.

See hurricanes.gov for public advisories on the active systems
and for the latest NHC Tropical Weather Outlook. See
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for the latest
High Seas Forecast.

...TROPICAL WAVES...

A tropical wave is entering the Caribbean Sea. The trough axis is
along 62W, south of 20N, and moving westward at 10-15 kt.
Scattered moderate to isolated strong convection is observed from
10N to 16N and between 57W and 62W. The convection is also
affecting the southern and central Lesser Antilles and localized
heavy rainfall is possible.

The tropical wave in the western Caribbean Sea has been
repositioned along 86W, south of 20N, based on satellite imagery,
sounding data from Grand Cayman, Cayman Islands, and Total
Precipitable Water. The wave extends across eastern Honduras,
western Nicaragua and Costa Rica and into the eastern Pacific, and
is moving westward near 15 kt. Numerous moderate to strong
convection is noted from 11N to 18N and between 81W and 87W.
Localized heavy rainfall is likely across portions of Nicaragua
and Honduras.

...MONSOON TROUGH/ITCZ...

The monsoon trough reaches the Atlantic through the coast of
Guinea near 10N14W and extends northwestward to a 1007 mb low
pressure near 19N28W (now TD 12 as of 1500 UTC), and continues
southwestward to 11N37W and 07N52W. Scattered moderate convection
is present from 03N to 13N and east of 21W associated in part with
the southwest flow into the Guinea Highlands.

...GULF OF MEXICO...

A stationary front is draped across the northern Gulf coast
producing a few showers and isolated thunderstorms within 90 nm of
the coastline. Farther south, a surface trough extends from the
mouth of the Mississippi River to the central Bay of Campeche and
a weak 1010 mb low pressure is noted along the trough near 25N91W.
Scattered moderate convection is seen on satellite imagery from
22N to 27N and between 88W and 93W. The remainder of the Gulf is
under a dry airmass that suppresses the development of convection.
The weak pressure gradient allows for mainly gentle to moderate
southerly winds west of 92W, along with seas of 2-4 ft. Elsewhere,
light to gentle winds and slight seas prevail.

For the forecast, a weak surface trough with moderate winds over the
central Gulf will drift westward as high pressure continues to
build over the Gulf waters. Moderate to locally fresh winds will
pulse at night off the NW Yucatan Peninsula through Sun night.
Otherwise, gentle to moderate winds will persist through early
next week with slight seas.

...CARIBBEAN SEA...

Please read the TROPICAL WAVES section for details on the
convection affecting parts of the Caribbean Sea.

Aside from the tropical waves, a dry airmass continues to
suppress the development of showers and thunderstorms across the
basin. The dry environment also allows for temperatures to soar
above normal and a heat advisory is in effect for portions of
Puerto Rico and the US Virgin Islands.

A recent scatterometer satellite pass captured fresh to strong
easterly trade winds across the central Caribbean. Seas in these
waters are 5-8 ft. Moderate to fresh easterly breezes and seas of
3-5 ft are evident in the eastern Caribbean and most of the NW
Caribbean. Elsewhere, light to gentle winds and slight seas
are prevalent.

For the forecast, fresh to strong trades will pulse in the
central Caribbean through tonight with moderate seas. Meanwhile,
gentle to moderate winds will prevail in the western Caribbean
with moderate to fresh winds in the eastern Caribbean. Trades will
weaken this weekend as the pressure gradient relaxes and continue
through early next week.

...ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section for details about Post-
Tropical Cyclone Idalia, Hurricane Franklin, Tropical Storm Jose,
Tropical Depressions Gert and Twelve.

Outside of the systems mentioned in the SPECIAL FEATURES section,
high pressure dominates the remainder of the tropical Atlantic,
supporting fairly tranquil weather conditions, moderate or weaker
winds and slight to moderate seas.

For the forecast W of 55W, Post-Tropical Cyclone Idalia is near
31.9N 67.9W at 11 AM EDT, and is moving east-southeast at 15 kt.
Maximum sustained winds are 50 kt with gusts to 60 kt, and the
minimum central pressure is 998 mb. Idalia will move to 31.3N
66.3W this evening, and become tropical near 30.9N 64.9W Sat
morning, and move N of area near 31.1N 63.7W Sat evening. Gale
force winds and rough to very rough seas associated with the
southern periphery of Idalia will impact the north waters through
the weekend. Tropical Depression Gert is near 28.7N 54.6W at 11 AM
EDT, and is moving east at 6 kt. Maximum sustained winds are 30
kt with gusts to 40 kt, and the minimum central pressure is 1008
mb. Gert will strengthen to a tropical storm near 28.8N 53.6W this
evening, and move to 28.9N 52.9W Sat morning. Then, Gert will
continue to move away for the offshore forecast waters the
remainder of the weekend. Strong winds and moderate seas will
impact the outer forecast waters due to Gert the rest of the day.

$$
DELGADO
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