[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241148 AAA
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
648 AM EST Sat Nov 24 2018

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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
1100 UTC.

...SPECIAL FEATURES...

...GALE WARNING IN THE ATLANTIC WELL NE OF BAHAMAS...

A cold front extends WSW from 32N46W to 28N56W, then continues as
a stationary front to a 1012 mb low near 25N71W. A warm front
extends NW from the low to 29N80W. Scattered moderate convection
is seen N of the warm front between 73W-80W, and from 24N-25N
between 67W-70W, and north of 23N between 47W-64W. Recent surface
observations and a scatterometer pass from around 0215 UTC
suggest winds are near 35 kt in the area within 120 nm north of
the low and front between 64W-72W with seas of 11 to 17 ft. Winds
will gradually diminish this morning as the low pressure moves
slowly N, then begins to accelerate NE across the western and
central Atlantic tonight through Sunday. Gales may redevelop
tonight east of 70W as the low approaches 30N. The system has a
low chance of becoming a subtropical cyclone before merging with
a frontal system by early next week. Please refer to the latest
HIGH SEAS FORECAST issued under the AWIPS/WMO headers
HSFAT2/FZNT02 KNHC.

...MONSOON TROUGH/ITCZ...

The monsoon trough emerges off the west coast of Africa over the
coast of Sierra Leone near 08N13W and extends to 04N19W. The
ITCZ continues from 04N19W to 00N26W to 00N47W. Scattered
moderate convection is observed from 03N-06N between 05W-13W.
Scattered showers are seen well north of the axis, from 09N-18N
between the W coast of Africa and 30W. Isolated showers are
elsewhere from 00N-19N between the W coast of Africa and 38W.

GULF OF MEXICO...

A 1009 mb surface low is centered over SE Louisiana near 30N90W.
A surface trough extends from the low to 26N90W to 24N96W to
20N96W in the SW Gulf of Mexico. A warm front extends from the
1009 mb low through Pensacola and Apalachicola Florida to
30N83W. Scattered moderate convection is observed from 24N-27N
between 82W-87W, and from 25N-27N between 91W-98W. Elsewhere,
isolated showers are over much of the NE Gulf. Isolated showers
are possible over the west-central and SW Gulf.

Satellite imagery and surface observations indicate patchy to
areas of dense sea fog this morning along the Gulf Coast
extending to 30 nm offshore into the Gulf of Mexico from the mid-
Louisiana coast to the Alabama coast.

The low will move E across the N Gulf coastal waters through this
evening, dragging a frontal trough across the northern waters
through tonight. Another cold front will move SE off the Texas
coast late Sun afternoon. The front will reach from the Florida
Panhandle to the W Bay of Campeche early Mon, then stall across
the far SE waters on Tue. Winds will increase briefly to minimal
gale force across the far W waters early Mon and then across the
SW waters of the Gulf Mon afternoon through evening.

CARIBBEAN SEA...

A weak surface trough extends from an Atlantic 1012 mb surface
low near 25N71W through the Windward Passage to 17N75W. No
significant shower activity is noted. Water vapor imagery shows
relatively dry conditions over the basin. The monsoon trough
near Panama is not producing significant convection at this
time, except for scattered showers and isolated thunderstorms on
the East Pacific side of Panama and southern Costa Rica.

A weak pressure gradient across the basin will maintain gentle to
moderate trades today. Fresh to locally strong trades are
expected across the tropical waters E of the Windward Islands.
Locally strong nocturnal trades will resume along the NW coast of
Colombia beginning tonight and lasting through Wed.

ATLANTIC OCEAN...

Please refer to the Special Features section above for details
relating to the evolution of the features associated with the
gale currently occurring well NE of the Bahamas. A surface trough
is analyzed from 29N49W to 25N53W. Convection associated with
this features was mentioned above. Scattered showers are noted
east of the cold front north of 30N between 39W-47W. Scattered
moderate convection is seen north of 31N between 26W-35W,
enhanced by upper-level diffluence in the area. A second surface
trough is just east of the Leeward Islands along 59/60W from 12N-
19N. Some isolated showers are possible with this trough over
the Lesser Antilles today. Elsewhere, broad high pressure of
1024 mb centered near 27N31W extends across the area and will
prevail through the weekend.

A new cold front will move off the SE United States coast on Mon
evening. This cold front will stall from 31N71W to the Florida
Keys Tue evening, then become reinforced Wed and reach from near
Bermuda through the central Bahamas to central Cuba Wed
afternoon.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Hagen
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