[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 242000 AAA
TWDAT

Tropical Weather Discussion...Updated
NWS National Hurricane Center Miami FL
300 PM EST Wed Jan 24 2018

Updated Gulf of Mexico section for convection

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
1945 UTC.

...SPECIAL FEATURES...

Caribbean Sea Gale Warning: The combination of high pressure in
the central Atlantic Ocean, and lower surface pressures in northern
Colombia will continue to bring pulses of strong to minimal gale
force NE to E winds along and near the coast of Colombia during
the overnight hours through Friday, and possibly for more time,
into the upcoming weekend. Sea heights are expected to be in the
range of 9 feet to 14 feet with the winds. Please read the latest
NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02
KNHC for more details.

Gulf of Mexico Gale Warning: As of 15Z, a cold front extends from
along and to just S of the Florida Keys southwestward to 24N84W,
where it becomes stationary to 23N90W to 21N94W to the central Bay
of Campeche near 20N94W and to just N of the coast of Mexico at
Coatzacoalcos. The earlier NW 25-35 kt gale force that were behind
the front S of 21N W of 95W have diminished for the time being,
but are forecast to increase again to gale force by early this
afternoon as the pressure gradient in the far SW Gulf along the
coast of Mexico in the vicinity of Veracruz tightens up again as
ridging that extends from strong high pressure centered over
eastern Texas presses southward along eastern Mexico and towards
the SW Gulf area. With this synoptic set-up taking form, the
tightening of pressure gradient from the building ridge will
maintain the northerly gale wind conditions into Thu before
diminishing to N to NE fresh winds. Please read the the latest
NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02
KNHC for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis emerges of the coast of Liberia, Africa
near 06N10W, and extends to near 04N16W. The ITCZ continues from
04N16W, to 02N26W to 01N34W to Equator at 30W. Scattered moderate
isolated strong convection is N of the ITCZ axis within 60 nm of
a line from 03N33W to 02N38W. Scattered moderate convection is
also N of the ITCZ within 30 nm of a line from 02N29W to 03N33W.

...DISCUSSION...

...THE GULF OF MEXICO...Updated

Please read the SPECIAL FEATURES section for details about the
cold front and associated gale-force northerly winds.

A cold front is analyzed from along and to just S of the Florida
Keys southwestward to 24N84W, where it becomes stationary to
23N90W to 21N94W to the central Bay of Campeche near 20N94W and to
just N of the coast of Mexico at Coatzacoalcos. A pre-frontal
trough is within 45 nm to its SE and E of western Cuba. Isolated
showers are seen along and SE of the trough. Over the far SW
Gulf, scattered moderate convection is over the SW Gulf from 20N
to 22.5N and between 92W and 96W. Latest available satellite
lightning data shows lightning strikes mainly in the eastern
sector of this convection. This is activity is forecast along
and near a surface trough that extends from just W of the tail
end of the stationary front northwestward to just SE of
Veracruz. It is being sustained by a strong jet stream branch
that stretches from the eastern Pacific eastern to across
central Mexico and over the northern portion of the gulf. Expect
for this activity to remain active through Thu. Scattered
showers and isolated thunderstorms are seen from 20N to 22N
between 94W and 96W. Areas of rain along with scattered showers
are present over the NW and N central waters to the northwest
and west of a line from just S of the western Florida panhandle
to 25N88W to 20N91W.

The eastern eastern portion of the front will move SE of the
Straits of Florida by Thu morning leaving a NW to SE orientated
trough across the far SW waters to meander through early Sat, then
lift back to the N as a warm front with a surface low expected to
developing along it near 27N90W on Sat night. The newly formed
surface low will move E on Sun, reaching the Florida Big Bend on
Sun night, while pushing a cold front across the Central Gulf
waters.

...THE CARIBBEAN SEA...

Please read the SPECIAL FEATURES section for details about the
gale-force winds for the area that is off the coast of Colombia.

Southerly upper level flow is noted over the just about the enter
basin, except over the far eastern portion where winds are
northwesterly behind the broad upper central Atlantic troughing.
Scattered showers and isolated thunderstorms are noted S of 16N
and W of 80W. Isolated showers and thunderstorms are elsewhere W
of 79W. Patches of low-level moisture advecting westward in the
easterly flow are seen over the eastern Caribbean waters, and also
approaching the northern Windward Islands. Scattered showers with
gusty winds are possible with this moisture.

The pressure gradient associated with high pressure N of the area
should support fresh to strong NE to E trades W of about 70W
elsewhere outside the gale force winds area described above
through Thu. Moderate to fresh trades are expected elsewhere
through Fri. Strong NE winds are expected through the Windward
Passage beginning late Thu. A cold front presently moving through
Straits of Florida and far SE Gulf of Mexico will move slowly
southeastward across the NW Caribbean this afternoon, then become
stationary, and gradually dissipate from Central Cuba to Belize
through Fri. Strengthening high pressure in the wake of the front
will produce fresh to strong NE winds across the NW Caribbean by
late Thu, with these conditions spreading eastward across the NE
Caribbean on Fri night through Sat. Moderate to fresh trades will
continue across the tropical Atlantic Ocean waters E of the
Windwards through Friday. Fresh to strong NE winds are forecast
from Fri night through Sun night. Conditions will improve across
the Caribbean from the NW on Sunday.

...THE ATLANTIC OCEAN...

A cold front extends from near 32N72W southwestward to 28N77W
to the Straits of Florida as of 15Z. A pre-frontal trough is
within 30 nm SE and S of the front. Isolated showers and
thunderstorms are along the trough portion NE of the Bahamas. A
surface trough is along a position from 31N37W to 26N38W to
21N38W.

A central Atlantic upper level trough is along a position from
32N42W to an upper low at 26N47W and continues to near 14N55W. A
second surface trough is along 49W from 19N to 26N. Visible
satellite imagery shows an extensive area of multilayer clouds
wrapping around in a cyclonic motion over the northern portion
of the trough. Scattered showers and isolated thunderstorms are
seen from 20N to 28N between 42W and 49W. A third surface trough
is along 54W/55W from from 21N to 30N. Isolated showers are
within 120 nm of the trough.

The aforementioned cold front will move slowly southeastward
and reach from near 31N69W to the Straits of Florida on this
evening, from near 29N65W to Central Cuba on Thu evening, and
then become stationary E to W along 23N on Fri night through Sat
night. The western portion of the front will lift N across the
Straits of Florida on Sun night. Strengthening high pressure in
the wake of this front will produce strong to near gale force NE-E
winds NW of the front Thu through Sat, with conditions improving
by Sun.

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

$$
Aguirre
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