[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280606
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Thu Sep 28 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 0000 UTC surface analysis and satellite imagery through
0500 UTC.

...SPECIAL FEATURES...

Tropical Storm Philippe is centered near 18.2N 54.5W at 28/0300
UTC or 490 nm E of the Northern Leeward Islands, and moving NW at
7 kt. Estimated minimum central pressure is 1002 mb. Maximum
sustained winds are 45 kt with gusts to 55 kt. Peak seas near and
just northeast of the center are from 20 to 22 ft. Numerous
moderate to scattered strong convection is noted up to 200 nm in a
E semicircle from the center. Philippe is expected to continue the
current motion through Friday, then gradually turn westward with a
decrease in forward speed this weekend. Little change in strength
is forecast during the next day or two, then a gradual weakening
trend should start this weekend. Philippe may produce 1 to 3
inches of rain across the northern Leeward Islands, the Virgin
Islands, and portions of Puerto Rico Saturday through Monday.
Heavy rainfall from Philippe may produce isolated urban and small
stream flooding impacts. 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
Philippe NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

Gale Warning Associated with Invest Area (AL91): A central
Atlantic tropical wave is near 44W from 17N southward through a
1006 mb low (AL91) near 15N44W, and moving west at 5 to 10 kt.
Scattered moderate to isolated strong convection is noted from
08N to 19N between 40W and 51W. Fresh to strong SE to SW winds and
8 to 12 ft seas are present from 12N to 21N between 40W and 44W.
These winds are going to reach Gale Force near 14N45W by Thursday
afternoon. 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 details.
Environmental conditions are forecast to be conducive for
development, as long as AL91 remains far enough away from Tropical
Storm Philippe to its west. A tropical depression or storm is
expected to form in the next day or so while the system moves
northwestward across the central tropical Atlantic. The chance of
development within the next 48 hours is high. Refer to the latest
Tropical Weather Outlook at hurricanes.gov for more information.

...TROPICAL WAVES...

Please refer to the SPECIAL FEATURES above for information on
the tropical wave associated with AL91.

A western Caribbean tropical wave is near 88W from near the east
Yucatan coast southward across Belize, western Honduras and El
Salvador to the East Pacific. It is moving west around 10 kt.
Widely scattered showers and isolated thunderstorms are occurring
at the northwestern Caribbean, including the Gulf of Honduras.
This feature will be carried over to the Tropical Weather
Discussion for the East Pacific.

...MONSOON TROUGH/ITCZ...

A monsoon trough enters the Atlantic along the Mauritania coast
just north of the Mauritania-Senegal border, then runs
southwestward across 13N20W to 07N26W. Numerous moderate
convection is noted south of the trough from 11N to 13N between
the Gambia-Guinea coast and 18W. There is no ITCZ presence based
on the latest analysis.

...GULF OF MEXICO...

A stationary front extends westward from near the Florida Big Bend
area to near New Orleans, Louisiana. Widely scattered moderate
convection is seen near and up to 50 nm along either side of this
front. A broad surface trough curves southwestward from the
east-central Gulf to the Bay of Campeche, while another surface
trough reaches southwestward from near Tampa, Florida to just
north of the Yucatan Channel. Isolated thunderstorms are found
across the central and east-central Gulf. Scattered showers and
isolated thunderstorms exist at the southeastern Gulf, including
the Florida Keys and Yucatan Channel. Moderate to fresh ENE winds
and seas of 3 to 5 ft are found near and north of the stationary
front. Gentle to moderate ENE to SE winds and 2 to 3 ft seas
prevail for the rest of the Gulf.

For the forecast, gentle to moderate NE to E winds and slight seas
will prevail across the Gulf through early Thu. Winds are
forecast to increase over the northern Gulf Friday into the
weekend as high pressure ridging strengthens over the southeastern
United States.

...CARIBBEAN SEA...

Refer to the Special Features section above for potential rainfall
related to Tropical Storm Philippe.

Enhanced by modest mid-level divergent flow, a surface trough is
causing widely scattered moderate convection from just east of the
Honduras-Nicaragua border northward to the Cayman Islands.
Convergent easterly trades are generating scattered showers and
isolated thunderstorms near eastern Cuba, Jamaica and Haiti. An
upper-level low near 14N68W is producing similar conditions at the
northeastern basin. Refer to the Tropical Waves section for
additional weather in the basin. Light to gentle monsoonal winds
and seas of 1 to 3 ft are found near Costa Rica and Panama. Gentle
to moderate with locally fresh ENE to SE winds and 3 to 5 ft seas
prevail elsewhere in the Caribbean Basin.

For the forecast, rough seas across the waters east of the
Leeward Islands generated by Tropical Storm Philippe well to the
east will start to subside this weekend. High pressure north of
the area will support moderate to fresh trade winds across most of
the eastern and central basin through tonight. Winds across the
Caribbean Basin will then diminish late this weekend.

...ATLANTIC OCEAN...

Refer to the Special Features section at the beginning on
Tropical Storm Philippe and a Gale Warning related to Invest AL91.

A stationary front extends west-southwestward from south of
Bermuda across 31N78W to near Daytona Beach, Florida. Convergent
southeasterly winds south of the front are coupling with abundant
moisture to trigger widely scattered showers and isolated
thunderstorms from the northwest Bahamas northward to where the
front is. The southern end of an upper-level trough is inducing
isolated thunderstorms well southwest of the Cabo Verde Islands
from 08N to 12N between 29W and 32W. Refer to the Monsoon
Trough/ITCZ section for additional weather in the Atlantic Basin.

A surface ridge extends westward from a 1021 mb high at the
eastern Atlantic near 29N32W to just east of the Bahamas. These
features are supporting light to gentle winds and 5 to 7 ft seas
in mixed north and east swells are present north of 25N between
25W and 70W. Farther west, gentle to moderate with locally fresh
ENE to E winds and seas of 5 to 7 ft in easterly swell are noted
north of 25N between 70W and the Georgia-Florida coast. Near the
Canary Islands, moderate to fresh NNE trades and seas at 4 to 7 ft
dominate from north of 18N between the Africa coast and 25W. At
the central Atlantic from 20N to 25N between 51W and 60W, fresh to
strong ENE to E winds and 8 to 14 ft seas are found. Otherwise,
gentle to moderate ENE to ESE winds and seas of 4 to 7 ft exist
from 20N to 25N between 25W and the Bahamas. Outside the direct
impact from Philippe and AL91, gentle to moderate ENE to SE to SW
winds with 6 to 8 ft seas in mixed swells are observed from 10N
to 20N between the Cabo Verde Islands and the Lesser Antilles.
Light to gentle monsoonal and southerly winds with 4 to 7 ft seas
in mixed south and north swells prevail for the remainder of the
Atlantic Basin.

For the forecast west of 55W, Tropical Storm Philippe will move
to 18.1N 55.1W Thu morning, 18.6N 56.5W Thu afternoon and 18.9N
57.7W Fri morning. It will then move to near 18.9N 58.8W Fri
afternoon, 18.8N 60.0W Sat morning, and 18.7N 61.6W Sat afternoon.
Afterward, Philippe will weaken to a remnant low near 18.4N 64.0W
Sun afternoon. Rough seas ahead of the storm are east of 60W, and
will continue to spread east of 65W through the end of the week.
Elsewhere, seas will build tonight and Thursday north of the
Bahamas and east of Florida in NE swell.

$$

Forecaster Chan
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