[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021737
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sat Sep 2 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
1730 UTC.

...SPECIAL FEATURES...

Tropical Storm Gert is centered near 27.8N 54.1W at 02/1500 UTC
or 620 nm ESE of Bermuda, moving NNE at 3 kt. Estimated minimum
central pressure is 999 mb. Maximum sustained wind speed is 45 kt
with gusts to 55 kt. Numerous moderate convection is within 150 nm
of the southern semicircle of Gert. Seas to 12 ft are within the
following quadrants as follows: 45 nm NE, 60 nm SE, 45 nm SW, and
0 nm NW. A faster northward to north-northeast motion is expected
to begin today and continue into Monday. Little change in strength
is expected before Gert is forecast to open up into a trough of
low pressure on Monday. Please read the latest HIGH SEAS FORECAST
issued by the National Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Gert
NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

Tropical Storm Katia is centered near 23.9N 29.7W at 02/1500 UTC
or 570 nm NNW of the Cabo Verde Islands, moving NNW at 10 kt.
Estimated minimum central pressure is 1000 mb. Maximum sustained
wind speed is 45 kt with gusts to 55 kt. Seas to 12 ft are within
the following quadrants as follows: 75 nm NE, 75 nm SE, 0 nm SW,
and 45 nm NW. A turn to the northwest is expected today, and this
general motion with a decrease in forward speed is expected
through Monday. Weakening is expected to begin by early Sunday,
and the system could degenerate into a remnant low on Monday.
Please read the latest HIGH SEAS FORECAST issued by Meteo-France
at website https://wwmiws.wmo.int/index.php/metareas/affiche/2 and
the latest Katia NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

Gale Warning: Post-Tropical Cyclone Idalia is centered near 31.6N
63.5W at 02/1500 UTC or 80 nm ESE of Bermuda, moving E at 8 kt.
Estimated minimum central pressure is 999 mb. Maximum sustained
wind speed is 50 kt with gusts to 60 kt. Seas to 12 ft impacting
TAFB waters extend 240 nm SE and 420 nm SW of the center of
Idalia. Seas 8 ft or greater in long period N swell is north of a
line from 31N55W to 23N68W to 31N78W. A faster northeastward
motion is forecast to begin on Sunday, followed by a turn toward
the north-northeast and north on Monday and Tuesday. On the
forecast track, Idalia will remain near Bermuda today, and then
begin to move away from the island tonight and Sunday. Little
change in strength is forecast during the next few days. Swells
generated by Idalia will affect the southeastern U.S. coast and
Bermuda during the next couple of days. These swells are likely to
cause life-threatening surf and rip current conditions; please
consult products from your local weather office. Please read the
latest HIGH SEAS FORECAST issued by the National Hurricane Center
at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the
latest Idalia NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

...TROPICAL WAVES...

A tropical wave is along 20W from 18N southward, moving W at 10-15
kt. Scattered moderate convection is from 09N to 12N between 20W
and 23W. Environmental conditions appear conducive for some
gradual development of this system by the middle part of next
week, and a tropical depression is likely to form while it moves
westward to west-northwestward at 15 to 20 mph over the eastern
and central portions of the tropical Atlantic. This tropical wave
has a LOW chance of development through 48 hrs.

A newly analyzed E Caribbean tropical wave is along 65W, from 18N
southward, moving west at 10-15 kt. Scattered moderate convection
is from 13N to 16N between 64W and 66W.

A central Caribbean Sea tropical wave is along 75W from 20N
southward, moving W at 10-15 kt. Scattered moderate convection is
in the SW Caribbean south of 10N between 76W and 83W.

...MONSOON TROUGH/ITCZ...

Scatterometer data indicates the monsoon trough extends from the
coast of Africa near 10N14W and continues to 05N21W then to
06N32W. No significant convection is noted at this time.

GULF OF MEXICO...

A stationary front is along the northern Gulf coast, from the
TX/LA border to near Cedar Key, FL. A surface trough extends from
the E Gulf near 27N84W through the Straits of Florida, with some
showers and tstorms evident along the trough on satellite imagery.
Another surface trough is in the SW Gulf, from 24N92W to 19N93W,
with showers and tstorms noted. Wind speeds may be locally
moderate near both troughs. Gentle to moderate E to SE winds
prevail across the basin, with seas of 2-4 ft.

For the forecast, the weak surface trough with moderate winds
over the central Gulf will drift westward through Sun as high
pressure continues to build over the Gulf waters. Winds and seas
could be higher near thunderstorms associated with the trough.
Moderate to locally fresh winds will pulse at night off the NW
Yucatan Peninsula through Tue night. Otherwise, gentle to moderate
winds and slight seas will persist through Wed across the basin.

CARIBBEAN SEA...

Fresh to locally strong trades are noted in the south-central
Caribbean, with seas of 5-7 ft. Elsewhere, trades are gentle to
moderate with seas of 3-5 ft. Scattered showers and tstorms are
noted in the NW Caribbean.

For the forecast, fresh to strong trades in the central Caribbean
will diminish today with the relaxing pressure gradient. Gentle
to moderate winds with slight to moderate seas will prevail
through the weekend. Fresh winds will return in the central and
eastern Caribbean by early next week and continue through Wed.

ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section for details about Post-Tropical
Cyclone Idalia, Tropical Storm Gert and Tropical Storm Katia.

A cold front enters the TAFB Waters near 31N62W, and continues
southwestward to 23N73W through the Bahamas then northwestward to
West Palm Beach, Florida. A pre-frontal trough is from 22N71W
parallel to Cuba through the Straits of Florida. Scattered showers
and tstorms are along the pre-frontal trough. A weak surface
trough is in the central Atlantic from 13N36W to 06N47W. A relaxed
pressure gradient across the basin, caused by the many tropical
cyclones disrupting the subtropical ridge, provides for light to
gentle winds across the basin with 4-6 ft seas.

For the forecast W of 55W, Idalia will move to 31.7N 62.5W this
evening, 32.9N 60.6W Sun morning, 34.7N 58.8W Sun evening, 36.8N
57.4W Mon morning, 39.0N 56.9W Mon evening, and 40.8N 57.4W Tue
morning. Idalia will change little in intensity as it moves near
42.3N 58.7W early Wed. Gale force winds and rough to very rough
seas associated with Idalia will impact the north waters through
the weekend. Conditions will improve by Mon night. Meanwhile,
Tropical Storm Gert will move to 28.5N 53.6W this evening, 30.1N
52.8W Sun morning, 32.6N 51.8W Sun evening, and dissipate Mon
morning. Gert will slowly move away from the eastern offshore
waters this evening and N of the area by Sun evening.

$$
Mahoney
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