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Atlantic Tropical Weather Discussion

AXNT20 KNHC 281108

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 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 0600 UTC surface analysis and satellite imagery through 
1050 UTC.


Tropical Storm Philippe is centered near 18.8N 54.6W at 28/0900 
UTC or 485 nm E of the northern Leeward Islands, and moving WNW 
at 5 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 20 to 22 ft. Seas of 12 ft or
greater extend outward up to 300 nm from the center in the N 
semicircle, 180 nm SE quadrant and 120 nm SW quadrant. Scattered 
moderate to strong convection is within 300 nm E semicircle, 120 
nm SW quadrant and 180 nm NW quadrant. A slow west-northwestward 
to westward motion is forecast during the next day or so, followed
by a slower westward to west-southwestward motion by this 
weekend. Little change in strength is forecast during the next day
or so, with slow weakening forecast this weekend. Please read the
latest HIGH SEAS FORECAST issued by the National Hurricane Center
at website and the 
latest Philippe NHC Forecast/Advisory and Public Advisory at for more details.

Gale Warning Associated with Invest Area (AL91): A 1006 mb low
pressure (AL91) is near 15.5N44.5W, and moving NNW at 10 kt.
Maximum sustained winds are near 30 kt and peak seas are about 13
ft. Numerous moderate scattered strong convection is noted within
180 nm of the center. Scattered moderate convection is elsewhere 
from 11N to 21N between 38W and 49W. Strong to near gale force
winds and 10-13 ft seas are present from 14N to 21N between 41W
and 47W. Winds are forecast to reach gale force later this
morning. By early Sat, the system could develop winds up to 40-45
kt and seas up to 16-20 ft as the low reaches near 19.5N49W. The
chance of tropical cyclone formation within the next 48 hours is
high. Please read the latest HIGH SEAS FORECAST issued by the 
National Hurricane Center at website - and the latest 
Tropical Weather Outlook at for more information.


A tropical wave extends southward from AL91 and is moving slowly


The monsoon trough enters the Atlantic along the Mauritania coast
near 18N16W to 07N26W. Scattered moderate isolated strong 
convection is noted from 06N to 16N between 13W and 20W.


A stationary front extends westward from near the Florida Big Bend
area to just south of New Orleans, Louisiana. Scattered moderate 
convection is seen near and up to 60 nm along either side of this
front. A surface trough is analyzed from near Naples, FL to near
Cancun, Mexico. Isolated to scattered thunderstorms are along and
southeast of this trough axis. Another broad surface trough
extends from the NW Gulf near 28N91W southward to the east-central
Bay of Campeche. Isolated thunderstorms are located within 60 nm
of the coast of southern Texas. Fresh E winds and 4-5 ft seas are
likely occurring to the north of the aforementioned stationary 
front. Elsewhere, gentle winds and 1-3 ft seas prevail.

For the forecast, the stationary front should move southward as a
cold front by Sunday. To the north of the front, fresh E winds 
are expected over the northern Gulf through the forecast period 
due to strong high pressure ridging over the southeastern United 


Total precipitable water imagery shows very moist air over the
northwest Caribbean. A surface trough is located off the coast of
southern Cuba, where scattered moderate convection is occurring.
Scattered thunderstorms are also noted in the Yucatan Channel and
in the Gulf of Honduras. Only isolated showers and thunderstorms
are seen over the central Caribbean, and over the SW Caribbean
attributed to the East Pacific monsoon trough. Moderate trades
prevail over much of the basin, except for gentle over the far
western Caribbean and over the far SE portion of the basin. Seas
range from 2 to 5 ft across the basin.

For the forecast, Tropical Storm Philippe will move to near 
18N58W early Sun morning, and weaken to a remnant low near 18N59W
early Mon morning. Rough seas across the forecast zones east of 
the Leeward Islands generated by Tropical Storm Philippe will 
start to subside toward the end of the week south of 17N, but will
continue 8 to 12 ft north of 17N into the weekend. Mainly 
moderate trade winds will prevail across the central Caribbean, 
with gentle to moderate winds elsewhere through the weekend.


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

A stationary front extends west-southwestward from 32N60W to
Daytona Beach, FL. Fresh to strong NE winds and 8 to 9 ft seas
prevail north of 30N and west of 79W. Scattered showers and 
isolated thunderstorms are located west of a line from 31N72W to 
22N78W. Elsewhere west of 65W, winds are moderate or weaker with 5
to 7 ft seas in mixed swell. Farther east, the subtropical surface
ridge extends east-west along 28/29N between 30W and 60W, anchored
by a 1020 mb high pressure centered near 29N32W. From 26N to 31N
between 30W and 60W, winds are light to moderate with 6 to 9 ft
seas in mixed swell. Winds of 20 to 45 kt and seas of 9 to 22 ft
associated with Tropical Storm Philippe and AL91 cover the area 
from 14N to 25N between 40W and 60W. Fresh to locally strong NE 
winds and 7 to 9 ft seas prevail north of the Cabo Verde Islands 
to 25N between the coast of Africa and 35W.

For the forecast west of 55W, Tropical Storm Philippe will move 
to near 19N57W by early Sat morning, 18N58W early Sun morning, and
weaken to a remnant low near 18N59W early Mon morning. Rough seas
ahead of the storm are east of 62W, and will continue to spread 
east of 68W through the end of the week. Elsewhere, fresh to 
strong NE winds and seas 8 to 9 ft will prevail through this 
evening north of the Bahamas and east of Florida in NE swell.
Looking ahead, AL91 could move west of 55W by Mon as a tropical