[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180603
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
102 AM EST Wed Dec 18 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 0000 UTC surface analysis and satellite imagery through
0545 UTC.

...SPECIAL FEATURES...

A cold front extends from 29N83W to 18N92W. Latest ASCAT data
shows Gale to storm force winds over portion of the western Gulf
from 18N-20N and west of 95W. This strong gale force winds will
continue through Wednesday afternoon in the southwestern Gulf of
Mexico, mainly south of 22N and west of 93.5W. Elsewhere behind
the front, winds of 25-30 kt will continue through tonight, with
frequent gusts to gale force south of 26N and west of 87W. Seas
of 11-17 ft will occur over portions of the southwestern Gulf of
Mexico through Wednesday morning. See the latest NWS High Seas
Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for further
details.

...MONSOON TROUGH/ITCZ...

The ITCZ passes through the coast of Sierra Leone near 08N13W to
01N29W to 01N47W. Scattered moderate convection is seen from 01N-
04N between 14W-38W. Scattered showers are seen near Brazil and
French Guiana extending 300 nm east offshore.

GULF OF MEXICO...

See the section above for details on the Gale Warning in the
Gulf of Mexico.

Since early this morning and latest ASCAT data shows fresh to
strong northerly winds behind the front across central and western
portion of the Gulf of Mexico. Gale force winds are also seen
over the western Gulf north of 20N and west of 94W. A squall line
extends from 26N83W to 30N80W ahead of the front. Scattered
moderate isolated strong convection is seen over the NE Gulf of
Mexico from North central Florida SE to the Yucatan Channel.
Convection is being enhanced by upper level diffluence. A surface
trough over the Yucatan Peninsula is also inducing scattered
moderate with isolated strong convection over the northern Yucatan
Peninsula, Yucatan Channel.

The squall line will continue racing east-southeast across the
rest of the eastern Gulf through late tonight. The front will move
southeast across the Gulf and extend from Tampa Bay Florida to
central Yucatan tonight, before moving southeast of the area Wed.
Northerly gale force winds and very large seas will prevail behind
the front, mainly W of 90W, through late Wed. Winds and seas will
diminish over the central and western Gulf Thu and Thu night.
Strong NE to E winds will continue over the Straits of Florida
after the frontal passage Thu through Fri night. Low pressure may
develop over the eastern Gulf Fri night and move across Florida
this weekend.

A heavy rainfall event is expected now through Wed for the Mexican
states of Chiapas, Tabasco southern portions of Campeche. Currently,
rains have already begun over much of the Yucatan Peninsula. In
Mexico, the maximum rainfall amounts may range from 4 to 6 inches.
The most intense rainfall is expected on Wed through Thu morning,
These rains will likely cause localized flooding and possible
mudslides.

CARIBBEAN SEA...

A surface trough over the Yucatan Peninsula is inducing scattered
moderate with isolated strong convection over the Yucatan Channel
as well as the east coast of the Yucatan Peninsula, the Gulf of
Honduras and Belize. Elsewhere in the NW Caribbean, scattered
showers extend to beyond the Cayman Islands, mainly north of 16N
between 79W-85W. In the far SW Caribbean, the east Pacific monsoon
trough is inducing scattered moderate with isolated strong convection
south of 11N between 73W-84W, including over Colombia and Panama.
Scattered light to moderate showers are seen over Puerto Rico and
Hispaniola. The ASCAT pass from late Tuesday morning shows fresh
to locally strong winds across the eastern and central Caribbean,
east of 81W, and light to moderate winds across the SW and NW
portion.

High pressure northeast of the region will maintain fresh to
strong trade winds and building seas from the tropical north
Atlantic west of 55W to the south central Caribbean through Sat.
A strong cold front will move through the Yucatan Channel late
Wed, then across the far northwest Caribbean before stalling and
weakening from central Cuba to central Honduras by late Thu. Fresh
to strong northerly winds will accompany the front. Looking ahead,
another front may move across the southern Gulf of Mexico and
approach the northwest Caribbean by late Sat, but the precise
timing remains uncertain at this time. Heavy rain is also expected
to affect northern and central Guatemala, much of Belize, and
northwestern Honduras tonight through Thu.

ATLANTIC OCEAN...

A cold front across the Southeast Plains continues to move SE
across Florida tonight. A pre-frontal squall line extends from
Jacksonville to Clearwater Florida. Another line of tstorms ahead
of that extends over the western Atlantic from near 28N79W to
31N74W. Expect these pre-frontal thunderstorms to continue moving
eastward through tonight, extending between 75W and the east
coast of Florida. The bulk of the moderate to strong storms will
remain north of 27N. Further east, a cold front extends from
31N34W to 28N52W, then stalls to 29N82W. Scattered showers are
seen along and 180 nm SE of the front.

High pressure over the area will continue to slide eastward
through Wed in response to a strong cold front currently over the
southeastern U.S. This cold front will move off the southeastern
U.S. coast late tonight, reach from near 31N70W to western Cuba on
Wed night, and then from 27N65W across the central Bahamas to
central Cuba on Thu night. Strong north to northeast winds and
building seas are expected across much of the forecast waters
following frontal passage. The front will gradually stall over the
central waters Fri and Fri night.

Looking ahead, fresh to strong easterly winds may persist Sat
across much of the western part of the area and NW Bahamas to
northeast Florida as low pressure develops in the Gulf of Mexico
and tracks in a general east to northeast direction. Exact timing
and location of this low remains uncertain.

$$
NATIONAL HURRICANE CENTER
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