[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161801
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sat Sep 16 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
1700 UTC.

...SPECIAL FEATURES...

Post-Tropical Cyclone Lee is centered near 43.5N 66.2W at 16/1500
UTC or 215 nm WSW of Halifax, Nova Scotia and moving N at 19 kt.
Estimated minimum central pressure is 965 mb. Maximum sustained
winds are 65 kt with gusts to 80 kt. Seas are peaking near 33 kt
near the center. Scattered moderate convection is seen near and up
to 200 nm in a NW semicircle from the center. A northward motion
will continue and Lee is expected to make landfall near or just
east of the U.S./Canada border this afternoon. Afterward, Lee
will turn toward the NE and move across Atlantic Canada tonight
and Sunday. Lee is going to remain near hurricane strength until
landfall this afternoon, then gradually weaken tonight and Sunday.
Please read the latest HIGH SEAS FORECAST issued by the Ocean
Prediction Center at website -
https://www.ocean.weather.gov/shtml/NFDHSFAT1.php for more
information.

Tropical Storm Margot is centered near 34.4N 38.7W at 16/1500 UTC
or 605 nm WSW of the Azores, and moving SW at 7 kt. Estimated
minimum central pressure is 996 mb. Maximum sustained winds are
45 kt with gusts to 55 kt. Peak seas of 20 to 22 ft are found near
and NW of the center. Scattered moderate convection is near and
south of the center from 32N to 34N between 36W and 40W. Margot
is expected to continue to make a slow clockwise loop during the
next day or two, then increase in forward speed toward the NE to E
early next week. A gradual weakening trend will continue for the
next couple of days, though slight fluctuations in intensity are
possible. Please read the latest HIGH SEAS FORECAST issued by the
Ocean Prediction Center at website -
https://www.ocean.weather.gov/shtml/NFDHSFAT1.php for more
information.

Tropical Depression Fifteen is centered near 19.7N 46.2W at
16/1500 UTC or 900 nm ENE of the Lesser Antilles, and moving NNW
at 16 kt. Estimated minimum central pressure is 1006 mb. Maximum
sustained winds are 30 kt with gusts to 40 kt. Peak seas are
around 12 ft near the center. Scattered moderate to isolated
strong convection near and north of the center from 19N to 24N
between 43W and 49W. A general NW or NNW motion is expected to
continue for the next few days. Strengthening is expected during
the next several days, and Fifteen should become a tropical storm
later this evening and could become a hurricane by early next
week. Please read the latest HIGH SEAS FORECAST issued by the
National Hurricane Center at website -
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more
information.

The latest NHC Forecast/Advisories and Public Advisories for all
three systems can be found at www.hurricanes.gov for more
details.

...TROPICAL WAVES...

An eastern Atlantic tropical wave is near 32W from 12N southward,
and moving westward at 10 to 15 kt. Widely scattered moderate
convection is seen from 06N to 12N between 26W and 36W.

...MONSOON TROUGH/ITCZ...

A monsoon trough enters the Atlantic near Banjul, Gambia then
curves southwestward through 10N25W to 11N35W. Scattered moderate
convection is occurring near and south of the trough from 06N to
14N between the Senegal-Liberia coast and 20W. There is no ITCZ
present based on the latest analysis.

The eastern end of the East Pacific monsoon trough is triggering
scattered showers and thunderstorms across the southwestern
Caribbean Sea from 11N to 13N between 76W and the southern
Nicaragua coast.

...GULF OF MEXICO...

A weak but persistent stationary front runs east-southeastward
from the Florida Panhandle to near Cap Canaveral, Florida. Widely
scattered showers and isolated thunderstorms are noted near and
up to 40 nm south of this feature. A surface trough curves
southwestward from near Galveston to Corpus Christi, Texas.
Scattered showers and thunderstorms are present near and off the
Texas coast, north of 25N and west of 94W. Otherwise, a 1014 mb
high at the central Gulf is promoting light to gentle winds and
seas of 1 to 3 ft across the entire Gulf.

For the forecast, the high will continue to dominate the Gulf
through early Sun, supporting mainly light to gentle anticyclonic
winds along with slight seas. A weak cold front is forecast to
move off New Orleans and Mississippi into the north-central and
northeastern Gulf Sun morning, followed by moderate N to NW
winds and isolated to scattered showers. The front is forecast to
move east of the area by Sun night. A weak surface ridge will
develop afterward, supporting gentle to moderate NE to E winds
through Wed. Otherwise, winds will pulse between moderate and
fresh west-northwest of the Yucatan Peninsula this evening and
Sun evening.

...CARIBBEAN SEA...

Widely scattered showers and isolated thunderstorms induced by
island heating are found near the southern coast of Hispaniola
and Puerto Rico. Refer to the Monsoon Trough/ITCZ section for
additional weather in the Caribbean Basin. A modest trade-wind
regime continue across most of the basin. Moderate to fresh
easterly winds and seas of 4 to 6 ft are present at the south-
central basin. Gentle to moderate ENE to E winds and 3 to 4 ft
seas are noted at the north-central and west-central basin. Gentle
to moderate monsoonal winds and seas at 2 to 4 ft exist near
Costa Rica and Panama. Mainly gentle easterly winds and 1 to 3 ft
seas prevail for the rest of the basin.

For the forecast, northerly swell affecting the northeastern
Caribbean Passages and the northern Tropical Atlantic will
gradually subside today. This swell will build again Sun night
through Wed as Tropical Depression Fifteen passes well northeast
of Caribbean Basin. Moderate to fresh trades will prevail across
the central basin with locally fresh to strong trades off
Colombia. Gentle to moderate winds will dominate elsewhere
through midweek next week.

...ATLANTIC OCEAN...

Please, read the Special Features section at the beginning for
details on Post-Tropical Cyclone Lee, Tropical Storm Margot and
Tropical Depression Fifteen.

A stationary front extends east-northeastward from near Cap
Canaveral, Florida to near Bermuda. Scattered showers and isolated
thunderstorms are found south of this front from 26N to 29N
between 74W and the Florida coast, including the northwest
Bahamas. A surface trough near 26N54W along with convergent
southerly winds to its west are causing scattered moderate
convection north of 21N between 52W and 68W. Refer to the Monsoon
Trough/ITCZ and Tropical Waves sections at the beginning for
additional weather in the Atlantic Basin.

Moderate to large northerly swell generated by Post-Tropical
Cyclone Lee is maintaining 7 to 10 ft seas north of 24N between
35W and 75W. Otherwise, light to gentle winds with seas at 5 to 7
ft in moderate mixed swells are found north of 20N between 55W and
the Georgia-Florida coast. Moderate to fresh with locally strong
easterly winds and 8 to 10 ft seas exist from 21N to 26N between
40W and 55W. For the eastern Atlantic, gentle to moderate NNE to E
trades and seas of 4 to 6 ft are found north of 10N between the
Africa coast and 40W, including the Canary and Cabo Verde Islands.
Farther west outside the direct impact from Tropical Depression
Fifteen, gentle to moderate NW to NE winds and seas of 4 to 6 ft
in moderate northwesterly swell are evident from 10N to 20N
between 40W and the Lesser Antilles. Light to gentle with locally
moderate southerly and monsoonal winds with 5 to 7 ft in moderate
southerly swell prevail for the rest of the Atlantic Basin.

For the forecast W of 55W, Tropical Depression Fifteen will
strengthen to a tropical storm near 21.3N 47.4W this evening, move
to 23.2N 49.0W Sun morning, 24.7N 50.4W Sun evening. It should
then strengthen to a hurricane near 26.2N 52.2W Mon morning, then
tracks to near 27.5N 54.1W Mon evening, and 28.9N 56.0W Tue
morning. Fifteen will change little in intensity as it moves N of
the area to 32.8N 58.3W early Wed. Otherwise, high pressure will
prevail across western Atlantic waters through the weekend. A
weak cold front is forecast to move off the southeast U.S. coast
early next week with new high pressure building down behind it.
The front may stall and linger along 27N/28N through midweek.

$$

Forecaster Chan
This weather bulletin was brought to you by:
www.nashvilleweather.net