[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041702
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1202 PM EST Sun Mar 4 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
1645 UTC.

...SPECIAL FEATURES...

Atlantic Storm Warning: Cold front extends from near 32N48W to
22N59W to Puerto Rico near 18N65.5W. A very tight pressure
gradient between the front and intense 973 mb low pressure
centered well north of the discussion area near 36N59W continues
to maintain 30 to 40 kt winds north of 25N and west of the front
to 73W along with large seas in the 14 to 29 ft range. Gale-force
SW to W winds are also present along the front N of 27N with
accompanying seas in the 15 to 20 ft range. The cold front will be
weakening as it reaches a position from near 32N43W to 25N50W to
near 17N62W Mon morning. A second round of even more vigorous
winds and seas can be expected Mon night and Tue morning as tight
low pressure develops within a trough that rotates around the
south side of the parent low over the Western Atlantic. Storm
conditions can be generally expected N of 29N between 52W and 65W
during this time frame, while gale conditions will prevail
southward as far as 27N. Gale conditions will persist through Wed
while shifting eastward over the central Atlantic. Please refer to
the Atlantic High Seas Forecast under the AWIPS header MIAHSFAT2
and under the WMO header FZNT02 KNHC for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends through the coastal sections of
Sierra Leone near 09N13W to 02N20W. The ITCZ continues from 02N20W
to 00N36W to end close to the Mouth of the Amazon near 01S51W.
There is no significant convection currently associated with these
features.

...DISCUSSION...

GULF OF MEXICO...

A strong and elongated ridge extends from the Ohio Valley over
the central Gulf to the Yucatan Peninsula and adjacent waters. The
ridge provides moderate NE to E winds over the eastern half of
the basin and E to SE moderate flow across the western Gulf.
GOES-16 animated water vapor imagery shows strong upper-level
ridging over the Gulf. Very dry air present in the mid to upper
levels is restricting convection and supporting mainly clear
skies. The surface ridge will slide eastward through Monday night,
thus allowing for the next cold front to move into the NW Gulf
early Tuesday morning. A secondary surge of cold air will push the
front across the rest of basin by Thu morning.

CARIBBEAN SEA...

The tail of a cold front associated with the intense low pressure
system over the NW Atlc extends across Hispaniola and the
Windward Passage to end just SW of the Yucatan Channel near
20N85W. No significant convection accompanies this weakening
boundary. Aside from shallow moisture associated with the front,
deep layer dry air is over most of the basin, which supports
mostly clear skies and fair weather conditions. The exception is
the SE Caribbean where a small area of convergent low-level flow
is supporting the continuation of cloudiness as well as scattered
to isolated showers over the southern Windward Islands and NE
Venezuela.

Large NE swell will continue affecting the tropical Atlantic
Ocean waters through mid week as the low pressure system lingers
over NW Atlc waters and secondary low pres develops on the S side
of the system. This will produce a large N to NE swell, that will
penetrate the NE Caribbean Sea Passages through Thu and reach the
A-B-C Islands as well as the coast of Venezuela. Otherwise, the
low pressure center will drag the weakening cold front through the
NE Caribbean tonight while it gradually dissipates.

ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section for more details about
the ongoing gale event over the western and central Atlantic.

A cold front associated with an intense low pressure system over
the NW Atlc, enters the area of discussion near 32N48W and
continues SW to 22N59W to Puerto Rico near 18N65.5W. Scattered
showers and isolated thunderstorms are occurring along and up to
120 nm ahead of the front N of 26N and along and up to 60 nm ahead
of the front between 22N and 26N. Strong to gale force winds
continue to persist behind this front. These conditions are
forecast to continue through Thursday as the front moves E into
the central Atlantic and weakens. The largest swell event thus far
this winter is already in progress and will be reinforced by the
development of secondary low pres just N of 32N55W on Tue. The
large swell will continue affecting all waters E of Florida and
the Bahamas through Wed. Another strong cold front is forecast to
impact the waters E of Florida Wednesday. Gales will be possible
along the front N of 30N as the front emerges from the Georgia and
Florida coasts.

Over the eastern Atlantic Ocean, a dissipating cold front
stretches from Mauritania on the coast of NW Africa near 21N17W
to end near 17N26W. No significant convection is present near the
front. Otherwise, moderate to fresh trades are noted over the
tropical Atlc S of 1019 mb high pres centered NW of the Canary
Islands near 23N27W.

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

$$
McElroy
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