[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171749
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1249 PM EST Tue Dec 17 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
1720 UTC.

...SPECIAL FEATURES...

A cold front is along 30N87W 19N95W. Expect NW-to-N gale-force
winds, and sea heights ranging from 8 feet to 10 feet, within
22N96W to 19N96W to 23N98W to 24N98W to 24N95W to 22N96W.
The gale-force wind conditions are forecast to continue until at
least Thursday morning, for the next 48 hours or so.
Please read the latest HIGH SEAS FORECAST: MIAHSFAT2/FZNT02 KNHC,
the latest OFFSHORE FORECAST: MIAOFFNT4/FZNT24 KNHC, or go to the
website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, everything
from the NWS National Hurricane Center, for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of Sierra
Leone near 09N13W to 06N15W and 01N17W, westward, to the Equator
along 35W, to 01S37W. Precipitation: widely scattered moderate to
isolated strong from 05N southward between 10W and 30W. More
precipitation: Widely scattered moderate to isolated strong also
is within 120 nm of the coast of Brazil and French Guiana, between
49W and 55W. Isolated moderate is within 600 nm to the ENE of the
coast of French Guiana.

GULF OF MEXICO...

A cold front passes through the Florida Panhandle, into the north
central Gulf of Mexico, into the west central sections of the
Gulf, to the coast of Mexico near 18.5N96W, and inland
northwestward into Mexico. Precipitation: scattered moderate to
isolated strong within 135 nm to the southeast of the cold front
from 25N northward. Isolated moderate is elsewhere within 120 nm
to the SE of the cold front from 20N to 25N.

The current strong cold front will move southeastward across the
Gulf of Mexico. The front will extend from Tampa Bay Florida to
the central Yucatan Peninsula tonight, before moving southeast of
the area on Wednesday. Northerly gale-force winds and very large
seas will prevail behind the front, mainly W of 90W, through late
Wednesday. The wind speeds and the sea heights will diminish in
the central and western Gulf of Mexico on Thursday and Thursday
night. Strong NE to E winds will continue in the Straits of
Florida after the frontal passage, from Thursday through Friday
night. It is possible that low pressure may develop in the eastern
Gulf of Mexico on Friday night, and move across Florida during
the upcoming weekend.

Strong northerly winds, today and on Wednesday, behind the front,
will result in heavy rainfall amounts between the Mexican States
of Veracruz and Tabasco/Campeche, from today into Wednesday. The
maximum rainfall amounts may range from 4 inches to 6 inches.
Additional rainfall amounts may range from 1 foot to 3 feet on
Wednesday and Thursday. The most intense rainfall is expected on
Wednesday and on Thursday, from NW Honduras to central Guatemala
(Puerto Barrios), a maximum of 6 inches to 8 inches. It is
possible that localized maxima may range from 10 inches to 12
inches, due to strong topographical forcing.

CARIBBEAN SEA...

The GFS model for 500 mb and for 700 mb shows broad cyclonic wind
flow, with an inverted trough, from the SW corner of the Caribbean
Sea within 300 nm of the coast of Colombia, and within 150 nm to
the north of Honduras. Precipitation: warming cloud top
temperatures and dissipating/weakening precipitation, covers the
SW corner of the area from 12N southward from 76W westward.
Widely scattered moderate to isolated strong from 16N to 23N in
the Yucatan Channel, between 80W and 87W.

High pressure, to the northeast of the region, will maintain
fresh to strong trade winds and building seas, from the tropical
north Atlantic Ocean from 55W westward, to the south central
Caribbean Sea through Saturday. A strong cold front will move
through the Yucatan Channel late on Wednesday. The front will move
across the far NW Caribbean Sea, before stalling and weakening
from central Cuba to central Honduras by late Thursday. Fresh to
strong northerly winds will accompany the front. It is possible
that a second cold front may move across the southern Gulf of
Mexico, and approach the NW Caribbean Sea by late Saturday. The
precise timing remains uncertain at this time.

ATLANTIC OCEAN...

A stationary front passes through 32N50W to 30N40W to 28N60W. The
front becomes dissipating stationary from 28N60W to 28N63W and
26N74W. Precipitation: isolated moderate within 30 nm on either
side of the line from 31N40W to 33N36W to 34N33W. Broken to
overcast multilayered clouds and possible rainshowers are from 27N
to 30N between 40W and 60W.

Broad upper level cyclonic wind flow and comparatively drier air
in subsidence cover the area that is from 10N to 20N between 40W
and 60W. High level clouds are curving anticyclonically, from
10N40W to 20N30W to 23N25W, and into the southern sections of the
Western Sahara.

The current dissipating stationary front will continue to become
weaker with time. A strong cold front will move off the southeast
U.S.A. coast late tonight. The strong cold front will extend from
31N70W to western Cuba on Wednesday night, and then from 27N65W
across the central Bahamas to central Cuba on Thursday night.
Strong N to NE winds and building seas are expected across much of
the forecast waters following the frontal passage. The front will
stall gradually, in the central waters on Friday and Friday
night. It is possible that fresh to strong easterly winds may
persist on Saturday, from the northern Bahamas to northeast
Florida, as low pressure develops in the Gulf of Mexico. The exact
timing and location are still uncertain.

$$
MT
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