[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041103
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
603 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 0600 UTC surface analysis and satellite imagery through
1100 UTC.

...SPECIAL FEATURES...
As of 04/0900 UTC, a vigorous middle to upper level trough is on
water vapor imagery over the eastern Gulf of Mexico and the west
N Atlc waters supporting a deepening and complex area of low
pressure focused on a 972 mb low near 34N74W. A cold front
extends from the low SW to 30N68W to the southern Bahamas near
22N72W through eastern Jamaica continuing to 15N80W. Gale force
winds are currently in place N of the Bahamas and west of the front
with seas to 18 ft. Hurricane-force winds are off the east coast
of the US north of the discussion area. The complex low will
continue to move N-NE offshore of the east coast of the US
reaching Nova Scotia, Canada by tonight. 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 in the SW Caribbean between surface
ridging in the NW basin and lower pressure associated with the
aforementioned cold front and a center of low pressure off central
Panama support gale force winds west of the low center. Latest
scatterometer data show gale force NW to N winds from 10N to 13N
west of 81W. These winds are forecast to diminish below gale
force before this afternoon. However, fresh to near-gale force
winds will prevail west of the front through early Friday morning. 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 04N08W to
04N20W. The Intertropical Convergence Zone axis extends from
04N20W SW to 01N30W to 01N38W. Scattered moderate convection is
from 02N to 08N between 16W-34W.

...DISCUSSION...

GULF OF MEXICO...

A strong surface ridge prevails across the Gulf anchored by a
1030 mb high centered north of Tampico, Mexico. A tight pressure
gradient east of the Sierra Madre Oriental, Mexico continue to
support fresh to near gale force winds south of 27N between 83W
and 98W. The ridge 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
eastern Cuba from 20N74W across eastern Jamaica to 15N80W. Ahead
of the front, an elongated surface trough extends from the
Windward Passage to a 1009 mb low off the coast of central Panama.
This area of low pressure is underneath diffluent flow aloft,
which is supporting scattered heavy showers and scattered tstms
between 71W and 83W, including the Windward Passage and
Hispaniola. Otherwise, the eastern Caribbean remains under fair
skies within moderate to occasional fresh trades. The cold front
is forecast to become stationary over Hispaniola Friday. Fresh to
near gale force winds are expected W of the boundary through the
upcoming weekend.

...HISPANIOLA...
Scattered showers are across Hispaniola due to an elongated area
of low pressure anchored by a 1009 mb low off the coast of central
Panama. A cold front currently moving off E Cuba into the Windward
Passage will move over Haiti tonight and then will stall there
Friday before dissipating over the weekend. NE winds will
increase 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 W Atlc, scattered showers and isolated tstms are across
the southern Bahamas and the approaches to the Windward Passage
being supported by a diffluent environment aloft. The remainder
of the central and eastern Atlc is under the influence of a
surface ridge anchored by a 1034 mb high centered W-SW of the
Iberian peninsula near 35N14W.

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

$$
Ramos
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