[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251701
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1201 PM EST Wed Dec 25 2019

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 1200 UTC surface analysis and satellite imagery through
1640 UTC.

...SPECIAL FEATURES...

...CENTRAL ATLANTIC GALE WARNING...

A 1007 mb low is near 31N54W, with a developing cold front
extending SW from the low to 27N59W. Gale force winds are
currently occurring in the eastern semicircle of the low, north of
29N. Gales will continue in the eastern and southern quadrants of
the low, and east of the cold front, north of 28N, as the system
moves eastward and then east-northeastward during the next 24
hours. Gales are forecast for the area north of 28N between 40W-
53W this afternoon and evening. Thursday morning, gales are
expected north of 29N between 35W-43W. Winds will decrease to
below gale force, south of 32N, by late Thursday afternoon. Seas
of 10-14 ft will develop this afternoon, with 12-16 ft expected
by this evening. Please refer to the latest NWS High Seas Forecast
issued by the National Hurricane Center under AWIPS/WMO headers
MIAHSFAT2/FZNT02 KNHC for further details.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the west coast of Africa near the
Sierra Leone/Liberia border near 07N11W to 05N15W. The ITCZ
extends from 05N15W to 04N38W to the coast of NE Brazil near
00N50W. Scattered moderate with embedded isolated strong
convection is seen within 75 nm either side of the ITCZ between
25W-36W. Isolated moderate convection is within 75 nm of the ITCZ
between 36W-46W.

GULF OF MEXICO...

A 1016 mb surface high is over the western Gulf near 25N93W. Mid-
upper level ridging covers the eastern and central Gulf of Mexico.
A surface trough is analyzed from 23N86W to 27N89W, with little to
no precipitation noted. The latest ASCAT pass shows moderate E
winds east of the surface trough. Gentle anticyclonic winds
prevail west of the surface trough.

The weak surface trough that is currently from 23N86W to 27N89W
will drift westward across the central and western Gulf today
through Fri, with fresh to locally strong E to SE winds east of
the trough. A cold front is forecast to enter the NW Gulf Sat
night into Sun followed by fresh to strong northerly winds and
building seas.

CARIBBEAN SEA...

A cold front extends from Haiti near 20N72W to 17N76W. A
stationary front extends from 17N76W to 13N79W, dissipating to
12N80W. Isolated showers are along the front. Isolated tstorms are
seen over the Dominican Republic. In the far SW Caribbean, the
east Pacific monsoon trough is inducing numerous moderate with
embedded isolated strong convection from 8.5N-11N between 79W-83W,
including over western Panama and far SE Costa Rica. The latest
ASCAT pass shows strong SE winds in the SE Caribbean from 12N-14N
between 65W-68W, but these winds should decrease to fresh this
afternoon. Gentle winds currently prevail across the central
Caribbean between 70W and the front. Fresh to strong N winds are
seen between the front and the coasts of Nicaragua and Costa Rica.

The front extending from western Haiti to 13N79W will dissipate
by tonight. Fresh to strong N winds are expected west of the front
to the coast of Nicaragua today. Winds and seas will diminish
across the central Caribbean on Thu, then increase again on Fri as
high pressure builds N of area.

ATLANTIC OCEAN...

Refer to the section above for details on the Gale Warning
currently in effect for the central Atlantic.

A 1003 mb surface low is centered near 29N69W. A surface trough
extends westward from the low to Stuart Florida, with little to no
shower activity noted along the trough. An occluded front extends
from the low to a triple point near 30N65W. A cold front extends
from 30N65W to 25N66W to 21N71W to Haiti near 20N72W. A warm front
extends from 30N65W to 27N59W. The surface low and front are being
supported by a strong mid-upper level low near 27N69W. Ahead of
the cold front, numerous moderate with embedded scattered strong
convection is seen within 60 nm either side of a line from 27N60W
to 24.5N63W to 21.5N66.5W, as of 25/1600 UTC. These strong
thunderstorms are likely producing wind gusts to gale force.
Scattered moderate convection is elsewhere within the area bounded
by 32N65W to 21N68W to 32N49W to 32N65W. The latest ASCAT pass
shows 25-30 kt NE winds, north of a line from 31N66W to 30N69W to
28N75W. An altimeter pass from 25/1026 UTC shows wave heights of
10-12 ft from 30N-32N near 72W-73W.

Farther E, a 1024 mb surface high is near 30N31W, with a surface
ridge axis extending west-southwestward from the high to the
Lesser Antilles. An east Atlantic cold front extends from 32N16W
to 25N24W. Scattered showers are seen over water from 24N-32N
between 10W-22W.

The low pressure system centered near 29N69W will continue to
affect the forecast waters through Thu, then shift eastward. The
pressure gradient between the low pres and high pres building
across the US eastern seaboard will support fresh to strong NE to
E winds, from 25N-30N on Thu, and from 21N-27N on Fri, between 60W
and the NW Bahamas.

$$
Hagen
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