[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221805
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
105 PM EST Thu Feb 22 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
1745 UTC.

...SPECIAL FEATURES...

Caribbean Sea Gale Warning: A tight surface pressure gradient
continues to exist, between comparatively higher surface pressures
in the western Atlantic Ocean and lower surface pressures in
northern sections of S America. This pattern is supporting winds
reaching gale force strength from 11N to 13N between 74W and 77W.
Waveheights within the area of gale force winds will range from
12-14 feet. These winds are forecast to diminish below gale force
early this afternoon, then develop again tonight and Fri night.
Please read the latest NHC High Seas Forecast under AWIPS/WMO
headers MIAHSFAT2/FZNT02 KNHC for more details.

Please refer to the METEO-FRANCE High Seas Forecast, that is
listed on the website: WWW.METEOFRANCE.COM/PREVISIONS-METEO-
MARINE/BULLETIN/ GRANDLARGE/METAREA2. Gale-force winds are
forecast for the areas: IRVING and METEOR. The OUTLOOK, for the
24 hours that follow the forecast that is valid until 23/0000
UTC, consists of: the threat of NW near gale or gale in IRVING
and in METEOR.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coastal sections of
Guinea near 10N14W to 03N19W, where latest scatterometer data
indicated it transitions to the ITCZ dropping below the equator
at 24W. Scattered moderate to strong convection is within 30 nm
of the axis between 11W-15W. Scattered moderate isolated strong
convection is seen S of 04N between 30W- 42W. Scattered moderate
convection is S of 03N between 24W-26W.

...DISCUSSION...

GULF OF MEXICO...

A weak cold front that moved into the far NW Gulf during the
overnight hours has become stationary along a position from near
the Texas/SW Louisiana border to a 1020 mb low at 27N96W and to
inland the coast of Mexico at 24N98W as of 15Z this morning.
Isolated showers and small patches of rain are along and NW of the
front and low per latest NWS radar imagery. Stratus clouds and
areas of dense fog with visibility 1 nm or less are observed along
the coast of Texas, and east from there to within about 75 nm of
that coast. Similar areas of dense fog are along the coast of
Mexico N of 19N. The fog is expected to linger into this evening.
A terrain induced weak low of 1019 mb is near Tuxpan with a
trough extending southeastward to 20N96W, and another trough
extending northward to 23N97W. The stationary front is forecast to
begin to lift back N as a warm front today. A weak cold front is
expected to slowly move to the Texas coastal late on Sun, then
move southeastward reaching from the Florida panhandle to Veracruz
by Mon afternoon. The gradient associated with strong high
pressure that extends from the western Atlantic to over the
eastern and central gulf waters will maintain fresh east to
southeast winds to the E of the front and low, with the exception
of strong east winds across the Straits of Florida through tonight
before diminishing to mainly fresh winds on Friday as the ridge
weakens.

CARIBBEAN SEA...

Please read the SPECIAL FEATURES section for details regarding
the Gale Warning that is in effect for the waters near the coast
of Colombia.

Scattered to broken low clouds with scattered showers and
isolated thunderstorms are associated with a shear line,
and are noted from 15N-17N east of about 67W. Gusty winds
can be expected with these showers. Strong surface high pressure
across the NW Atlantic Ocean will dominate the region, settling
across the Bermuda area through Sat. Fresh to strong trade winds
will prevail across the Caribbean Sea and the Tropical N Atlantic
Ocean today, with nocturnal winds expected along the coast of
Colombia expected to diminish to just below gale force early this
afternoon, then pulse back to gale force tonight and Fri night.
Surface high pressure will weaken through the weekend leading to
diminishing winds and seas.

ATLANTIC OCEAN...

An upper level trough extends from an upper low dropping southward
N of the area at 34N28W through 32N29W to 24N38W, then continues
as a cyclonic shear axis to 23N46W to 21N56W and to the NE
Caribbean Sea. The trough supports a cold front that enters the
area at 32N23W, and continues to 25N24W to 18N33W, where it
transitions to a shear line to 17N38W to 16N48W to just S of
Martinque and to the eastern Caribbean Sea at 17N71W. Broken low
level clouds with scattered showers are within 45 nm either side
of the shear line. The surface low associated with the upper low
at 32N28W is forecast to intensify as it quickly drops southward
reaching to near 29N26W with a pressure of 998 mb by early on Fri.
Strong to gale force winds will accompany the low along with large
seas. An associated cold front is forecast to extend from near
25N35W to 25N44W to 28N49W by early on Sat. Strong to near gale
force NW to N winds and seas of 10-17 ft are expected to the
north of a line from 25N35W TO 25N44W TO 28N49W at that time.

A western Atlantic ridge will persist along 33N/34N through Fri,
then slowly move southwestward and weaken slowly through the
weekend. Patches of low clouds moving quickly westward with
isolated showers will continue to the S of 26N and west of 50W
outside those associated with the aforementioned shear line.
Gentle to moderate winds will prevail N of 25N, with fresh to
strong winds S of 25N through Thursday. NNE swell will move
through the waters that are to the E of 65W through Friday night.
It is possible that a weak cold front may move off the NE Florida
coast early next week.

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

$$
Aguirre
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