[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201743
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1242 PM EST Sat Jan 20 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 1200 UTC surface analysis and satellite imagery through
1730 UTC.

...SPECIAL FEATURES...

Broad strong high pressure over the SW N Atlc waters will
continue to move eastward while slightly strengthening the next
two days.
This is currently supporting fresh to near gale-force winds in
the south-central Caribbean waters with the strongest winds being
along the coast of NW Colombia. The pressure gradient in this
region is expected to slightly increase tonight, thus leading to
the development of gale-force winds along Colombia. Gale winds
are expected to continue through Sunday morning, but remain in
the strong to near-gale range through Monday. See the latest NHC
High Seas Forecast under AWIPS/WMO headers MIAHSFEP2/FZPN03 KNHC
for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean near 07N12W and
continues to 03N16W to 01N21W. The ITCZ begins near 01N21W and
continues along 01N40W to 01S50W. Scattered moderate rain showers
are from 01N to 06N between 10W-18W and within 175 nm either side
of the ITCZ.

...DISCUSSION...

...GULF OF MEXICO...

A broad surface ridge extends from the SW N Atlc waters across
Florida, the SE CONUS, into the Gulf and into inland Mexico. This
setting is providing the basin with light to moderate return
flow, except for locally fresh wind off the coast of Texas. A
middle to upper level low centered between Louisiana and
Mississippi extends a trough S-SW across the basin. To the east,
SW flow associated with the NW periphery of a ridge centered in
the south-central Caribbean supports diffluent flow, which is
supporting cloudiness and possible isolated showers across the E
Gulf, the Yucatan Channel and the Florida Straits. A weakness in
the ridge analyzed as a surface trough along the SE coast of
Florida into the Straits of Florida may enhance the shower
activity for the SE Gulf. Otherwise, low level moisture
convergence support isolated showers over Louisiana adjacent
waters as indicated by radar imagery. The next cold front will
come off the coast of Texas Monday morning, extend from the
Florida Big Bend SW to near Tuxpan, Mexico Tuesday morning and
then is expected to stall over  South Florida to the central
Gulf waters Wednesday. Remnants of the front will lift N late on
Wed, with strong NE winds developing across the NW Gulf waters.

...CARIBBEAN SEA...

A broad middle to upper level ridge centered over the south-
central waters covers the Caribbean. Diffluent flow in the
western periphery of this ridge along with moderate to high low
level moisture support scattered showers within 175 nm west of a
surface trough that extends along Nicaragua, Costa Rica and
northern Panama adjacent waters. Isolated showers are elsewhere
west of 75W. The tail of a weakening stationary front extends
across the Windward Passage to near 18N80W supporting isolated
showers in that region and over portions of Hispaniola. Shallow
moisture in the trade winds may support scattered to isolated
showers across Puerto Rico and adjacent waters. Otherwise,
strong high pressure over SW N Atlc waters supports fresh to
near-gale force winds in the south-central basin, increasing to
gale-force off the coast of Colombia tonight through Sunday
morning. See the Special Features section for more details.

...HISPANIOLA...

Partly cloudy skies prevail across the island as the tail of a
weakening stationary front extends across the Windward Passage
towards western Jamaica adjacent waters. Isolated showers are
occurring along the northern half of the Island. Similar weather
conditions are forecast through Sunday morning as the front
dissipates. Fresh northeasterly winds will continue across the
Windward Passage through tonight and then it will limit to the
Atlc approaches as the ridge slides towards the central Atlc
waters.

...ATLANTIC OCEAN...

Strong high pressure covers the SW N Atlc waters being anchored
by a 1026 mb high near 29N72W. A weakness in the ridge is
analyzed as a surface trough along the SE Florida coast SW
towards the Straits of Florida. This surface feature in
underneath diffluent flow aloft between a trough over the Gulf
and a broad ridge covering the Caribbean Sea. This scenario
support cloudiness and possible isolated showers in the northern
Bahamas, the Great Bahama Bank and the straits. A broad middle
to upper trough over the north-central Atlc with base near 30N
continue to support a cold front that extends from 30N47W SW to
22N59W to 21N67W. From 21N67W, the front transitions to a
weakening stationary front that traverses the Windward Passage.
Scattered to isolated showers are N of 24N between 40W and 55W.
The remaining eastern Atlc is under the influence of the Azores
high that extends a ridge axis near 23N.
The front in the central Atlc will continue to weaken as it loses
support from aloft. A remnant surface trough is forecast in the
central waters by Monday morning. The next cold front will exit
the NE Florida coast Tuesday afternoon.

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

$$
Ramos
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