[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041206
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
706 AM 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 0600 UTC surface analysis and satellite imagery through
1100 UTC.

...SPECIAL FEATURES...

Atlantic Gale Warning: Cold front extends from near 32N48W to
22N60W to the eastern Dominican Republic near 19N70W. A very
tight pressure gradient between the front and intense low pressure
well north of the discussion area continues to maintain W to NW
30 to 40 kt winds north of 26N and west of the front to 72W along
with large seas in the 18 to 31 ft range. Gale-force SW to W
winds are also N of 29N within 90 nm east of the front with
accompanying seas in the 17 to 20 ft range. The cold front will
be weakening as it reaches a position from near 32N44W to 25N51W
to near 18N60W tonight. A second round of even more vigorous
gales between 35 kt and 45 kt with seas of 18 to 32 ft can be
expected Mon night and Tue morning N of 27N between 52W and 67W as
tight low pressure develops within a trough rotates around the
south side of the parent low over the Western Atlantic. Gale
conditions will persist through Mon while shifting eastward to 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 04N17W to 02N21W. The ITCZ continues
from 02N21W to 00N30W then along the Equator to the coast of
Brazil near 00N46W to end 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 lower and
middle levels is 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 and 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 Island and NE Venezuela.

Large NE swell will impact 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 today into next week
reaching the A-B-C Islands and coast of Venezuela. Otherwise, the
low pressure center will drag the cold front into the northeast
Caribbean tonight while it gradually dissipates through early next
week.

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 22N60W to NE Hispaniola. Aside from scattered
showers and isolated thunderstorms along and up to 120 nm ahead of
the front N of 26N, strong to gale force winds continue to
persist behind this front. These conditions are forecast to
continue through Tuesday as the front moves E towards the central
Atlantic. The largest swell event thus far this winter is already
in progress and will accompany this system as it progresses,
affecting all waters E of Florida and the Bahamas through early
next week. 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 it emerges from the Georgia and Florida coasts.

Over the eastern Atlantic Ocean, a cold front stretches from the
coast of NW Africa near 22N17W to 20N21W where it continues as a
nearly stationary front to 19N40W. No significant convection is
present near the front.

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

$$
McElroy
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