[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171721
TWDAT

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
1700 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 12N15W
to 02N25W. The ITCZ continues from 02N25W to 01N37W. Numerous
moderate and scattered strong convection is observed within 360
nm of the coast of Liberia and Sierra Leone, east of 17W from
02S-07N. Isolated showers are within 210 nm N and within 180 nm
S of the ITCZ and monsoon trough between 20W-36W.

GULF OF MEXICO...

A cold front is moving off the Texas coast and into the far
western Gulf of Mexico now, as of about 17/1700 UTC, from
roughly Houston TX to 27.5N96.5W to the Mouth of the Rio Grand
River. Ahead of the front, fresh to strong S to SE winds prevail
across the central Gulf of Mexico, per the latest ASCAT pass,
where seas are likely 6 to 8 ft. A pre-frontal line of scattered
showers and tstorms has formed offshore of Texas, mainly north
of 27N, extending northward to the Texas/Louisiana border. This
line of tstorms will move from west to east across the NW Gulf
this afternoon. By midnight tonight local time, the line of
tstorms will be near the coast of Mississippi and SE Louisiana.
Some of the tstorms to the north of 28N are likely to be strong,
with frequent lightning, gusty winds, small hail and isolated
waterspouts.

The cold front will reach from the Florida Panhandle to the Bay
of Campeche on Thu, and from southern Florida to the Yucatan
peninsula on Fri. Near gale-force NW winds are expected near the
Veracruz coast of Mexico Thu afternoon. The strong winds will
end by Thu night. Seas will peak around 8-10 ft in the area of
strongest winds Thu afternoon and Thu evening, then subside Thu
night as the winds diminish. Fresh to strong winds and building
seas are expected in the NE Gulf Sat night through Sun night.

CARIBBEAN SEA...

A recent ASCAT pass indicates the presence of a surface trough
in the SW Caribbean from the SE coast of Nicaragua to the N
coast of Panama near 09N80W. This surface trough and a mid-level
trough over the southern portion of Central America are
enhancing scattered moderate to strong convection over the SW
Caribbean from 09.5N-12N between 80W-83.5W, or within 180 nm of
the coasts of western Panama, Costa Rica and SE Nicaragua. Heavy
rain could impact the southeast coast of Nicaragua this
afternoon through tonight.

A cold front extends from west of the Azores near 38N33W to
Antigua near 17N62W to just south of Puerto Rico and ending
inland over the Dominican Republic. Cloudiness with possible
scattered showers are within 45 nm either side of the front,
including near Antigua, Montserrat, Nevis and the Dominican
Republic. The cold front is forecast to drift SE across the NE
Caribbean through Thu. A surface trough extends from St. Lucia
east-northeastward to 17N53W. Scattered showers are possible
near St. Lucia and Martinique.

The latest ASCAT pass shows fresh winds covering most of the
Caribbean, with strong NE to E winds over the central Caribbean.
Strong E to SE winds are also likely occurring in the Gulf of
Honduras. Seas are likely currently 7-10 ft in the central
Caribbean, 5-8 ft in the eastern Caribbean and 4-7 ft in the NW
Caribbean, except 6-8 ft in the Gulf of Honduras. Strong trade
winds will continue across the central Caribbean through Fri
morning, with near gale-force winds expected near the coast of
Colombia each night. Fresh to strong winds are expected in the
Windward Passage tonight. SE winds will increase across the NW
Caribbean through tonight, ahead of a cold front moving into the
Gulf of Mexico. The front will stall and weaken near the Yucatan
Channel Fri night and Sat. Large northerly swell will affect the
Tropical N Atlantic waters and NE Caribbean Passages through Thu.

ATLANTIC OCEAN...

A cold front extends from 34N73W to Savannah Georgia. Ahead of
the front, scattered moderate showers and tstorms are occurring
from 29.5N-32N between 70W-77W. Fresh S to SW winds are located
in the same area. Gentle anticyclonic winds prevail elsewhere
north of 22N and west of 60W, due to surface ridging. An
exception is in the Florida Straits, where fresh SE winds are
seen on the latest ASCAT data pass.

A cold front extends southwestward across the central Atlantic
from 32N36W to 21N50W to Antigua near 17N62W, and across the NE
Caribbean, ending inland over the Dominican Republic. The latest
ASCAT data pass shows fresh NE winds north of the front to 22N
between 52W-70W. These winds are locally strong just north of
the Mona Passage. A pre-frontal surface trough is analyzed from
30N36W to 18N47W. Cloudiness and scattered light showers are
along the cold front and the surface trough. Large NW to N swell
of 10-20 ft covers the Atlantic behind the cold front and east
of 65W, highest near 31N43W. Seas are 6 to 9 ft east of the
Bahamas, in N swell.

For the forecast, a cold front will move east of northern
Florida Thu night, extend from near 31N71W to the Straits of
Florida Fri night, then become stationary on Sat. An area of low
pressure forming along the stationary front will intensify
northerly winds east of northern Florida Sun and Sun night, with
gale conditions possible. Farther east, the cold front from
21N50W to the NE Caribbean will drift SE today. Large northerly
swell will continue to affect the waters E of 72W through Thu,
then gradually diminish afterwards. Aside from some fresh to
locally strong NE winds occurring Fri and Sat near 28N45W, south
of a developing high pressure, the trade winds across the
central Atlantic will remain moderate to fresh.

$$
Hagen
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