[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040602
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
102 AM EST Thu Jan 4 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 0000 UTC surface analysis and satellite imagery through
0545 UTC.

...SPECIAL FEATURES...
As of 04/0300 UTC, a vigorous middle to upper level trough is
noted on water vapor imagery over the eastern Gulf of Mexico and
the SW N Atlc waters supporting a deepening and complex area of
low pressure focused on a 997 mb low near 31N74W and a 993 mb low
near 31N76W. A cold front extends from the easternmost low SW to
the northern Bahamas near 25N76W through central Cuba continuing
to eastern Honduras. A warm front also extends E from the
eastern low to near 31N52W. The eastern low is forecast to merge
with the western low as it continues to rapidly intensify while
moving to the NE. Storm force winds are currently in place N of
the Bahamas from 28.5N to 31N west of the cold front with seas to
18 ft. Hurricane- force winds will develop off the east coast of
the US north of the discussion area within the next 24 hours. The
complex low will continue to move N-NE offshore of the east coast
of the US reaching Nova Scotia, Canada by Thursday night. See the
latest NWS NHC High Seas Forecast under AWIPS/WMO headers
MIAHSFAT2/FZNT02 KNHC and NWS OPC High Seas Forecast under
AWIPS/WMO headers HSFAT1/FZNT01 KWBC for more details.

A tight pressure gradient and reinforcing cold air filtering in
across the western Gulf of Mexico continues to support near gale
to gale force N-NW winds generally within 60 nm of the coast of
Veracruz, Mexico. These winds are forecast to diminish below
gale force before sunrise today. See the latest NWS High Seas
Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more
details.

...ITCZ/MONSOON TROUGH...
The monsoon trough extends from the African coast near 06N10W to
05N20W. The Intertropical Convergence Zone axis extends from
05N20W SW to the coast of Brazil near 03S39W. Scattered moderate
convection is from the Equator to 09N between 16W-30W.

...DISCUSSION...

GULF OF MEXICO...
Aside from the near gale to gale force conditions mentioned
above, a surface ridge prevails across the Gulf anchored by a
1030 mb high centered near Tampico, Mexico. Fresh to strong
northerly winds are expected to persist through Thursday morning.
Thereafter, the ridging will weaken gradually relaxing the
pressure gradient and winds will diminish into moderate breeze
levels for the upcoming weekend.

CARIBBEAN SEA...
Southwesterly flow aloft prevails over the Caribbean basin between
the base of an upper level trough over the northwestern
Caribbean, and an upper level ridge anchored east of the Windward
Islands. The trough aloft supports a cold front analyzed across
central Cuba from 21N79W to the eastern Gulf of Honduras near
16N85W. Isolated showers are possible within 60 nm either side of
the front. South of Jamaica, a 1009 mb low is analyzed near 13N78W
with a trough extending northward from the low to the Windward
Passage. This elongated area of low pressure is underneath
diffluent flow aloft, which is supporting scattered heavy showers
and scattered tstms N of the low between 71W and 80W. including
the Windward Passage and Hispaniola. Similar convection is S of
the low to the coast of Panama and Costa Rica. This convection is
being influenced by the EPAC surface trough and divergent flow in
the upper levels. Otherwise, the eastern Caribbean remains under
fair skies within moderate to occasional fresh trades. As the
Special Features low pressure area across the SW North Atlc waters
moves northward, the associated cold front will move across the
western Caribbean to 78W and become stationary across the Windward
Passage and Hispaniola today into Friday with fresh to near gale
force winds expected W of the boundary through the upcoming
weekend.

...HISPANIOLA...
Increased cloudiness and scattered to isolated showers are across
Hispaniola due to an elongated area of low pressure centered south
of Jamaica. A cold front currently across central Cuba and the NW
Caribbean Sea will begin to approach from the west on today with
NE winds increasing through the Windward Passage region and
persisting through early next week.

ATLANTIC OCEAN...
Outside of the Special Features deepening area of low pressure
across the SW North Atlc, a surface trough extends from 29N56W to
22N70W supporting scattered showers and isolated tstms within 150
nm either side of the boundary. The remainder of the central and
eastern Atlc is under the influence of a surface ridge anchored by
a 1033 mb high centered W-SW of the Iberian peninsula near
36N13W.

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

$$
Ramos
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