[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211748
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
148 PM EDT Mon May 21 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...

Upper level cyclonic wind flow spans the Gulf of Mexico. A trough
extends from the Florida Panhandle, beyond the Yucatan Channel,
into the NW Caribbean Sea. This weather pattern is drawing deep
tropical moisture northward, from the SW Caribbean Sea between
76W and 84W. A surface trough in the Gulf of Mexico extends from
a 1015 mb low pressure center that is just off the coast of the
Florida Big Bend along 85W/86W, to 23N. A second surface
trough is in the western part of the Caribbean Sea, from 21N86W,
across eastern Honduras and NE Nicaragua, to 10N83W in the SW
Caribbean Sea. Precipitation: widely scattered to scattered
moderate and isolated strong rainshowers cover the areas that
extend from the SW Caribbean Sea, across Cuba, to Florida, and the
Bahamas and the nearby Atlantic Ocean. This activity is expected
to continue through at least Tuesday, with heavy rainfall and
possible flooding. Environmental conditions are expected to be
unfavorable for development during the next few days. Some gradual
development is possible later this week while the system moves
into the central or eastern Gulf of Mexico. Locally heavy rainfall
is possible across western Cuba and Florida during the next
several days.

...TROPICAL WAVES...

A tropical wave is along 29W/30W from 15N southward, based on
current satellite imagery, moving W 10 to 15 knots. This wave is
embedded in a sharp 700 mb trough. Precipitation: widely scattered
moderate to isolated strong from 02N to 05N between 29W and 32W.

A tropical wave is just to the east of the Caribbean Sea, along
20N58W 15N59W 10N61W, just to the west of Barbados. This wave
continues to appear as a 700 mb trough and has a poleward surge in
moisture associated with it. The tropical wave is moving through
an area of upper level cyclonic wind flow, that is moving around a
23N58W Atlantic Ocean cyclonic circulation center. Precipitation:
isolated moderate to locally strong rainshowers are from 12N to
23N between 52W and 65W.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of
Guinea near 09N13W, to 06N14W. The ITCZ continues from 06N14W
to 04N27W, and 01N37W. Precipitation: widely scattered moderate to
isolated strong rainshowers, in a disorganized pattern, are from
07N southward.

...DISCUSSION

GULF OF MEXICO...

Please read the Special Features section for more details about
the upper level trough and related surface weather features and
precipitation.

Scattered moderate to strong rainshowers are from 20N to 22N
between 96W and 99W, in the coastal sections of Mexico. This area
of precipitation has been moving southward during the day today,
from the border with Texas to its present position.

A surface ridge will remain in the northern Gulf Coast through
Thursday night. The current eastern Gulf of Mexico surface trough
will drift westward, into the central Gulf of Mexico, by
Wednesday. It is possible that a low pressure center may develop
in the the NW Caribbean Sea on Thursday, and move northward along
the trough into the south central Gulf of Mexico on Friday.

CARIBBEAN SEA...

Please read the Special Features section for more details about
the upper level trough and related surface weather features and
precipitation, from the Gulf of Mexico into the NW Caribbean Sea.

Upper level cyclonic wind flow cuts across the area, to the north
of the line that curves from Hispaniola to 13N67W to 13N60W. This
upper level wind flow is around the periphery of the 23N58W
Atlantic Ocean cyclonic circulation center. Comparatively drier
air in subsidence is apparent in water vapor imagery to the north
of the Hispaniola-to-14N60W line.

The monsoon trough is along 08N/09N from N Colombia beyond SE
Costa Rica, into the eastern Pacific Ocean. Precipitation: widely
scattered to scattered moderate and isolated strong rainshowers
are elsewhere from 05N to 11N between 73W and 81W.

Atlantic Ocean high pressure will maintain fresh to locally
strong trades in the central Caribbean Sea through Friday night.
Strong winds, and sea heights to 9 feet, will affect the NW coast
of Colombia. A surface trough will linger in the far western
Caribbean Sea through Thursday. It is possible that a low pressure
center may form along the trough in the Gulf of Honduras on
Thursday, and then move northward into the Gulf of Mexico on
Friday. Fresh to strong winds will develop in the central and
western Caribbean Sea from Thursday through Friday night, between
the surface trough and the Atlantic Ocean high pressure.

ATLANTIC OCEAN...

Please read the Special Features section for more details about
the upper level trough and related surface weather features and
precipitation, from the Gulf of Mexico into the NW Caribbean Sea.
The chances for heavy rainfall in Florida, across the Bahamas,
and in the western Atlantic Ocean will continue.

An upper level cyclonic circulation center is near 23N58W.
Cyclonic wind flow covers the Atlantic Ocean and parts of the
Caribbean Sea from 13N northward between 42W and 74W.

An east-to-west oriented ridge will be along 30N through Friday
night. The ridge will support fresh to locally strong E to SE
winds mainly S of 26N, including the Old Bahama Channel, and the
approaches to the Windward Passage through Wednesday. Fresh to
occasionally strong winds will prevail N of Hispaniola, mainly at
night. It is possible that a broad area of low pressure may
develop in the NW Caribbean Sea and move northward across the
eastern Gulf of Mexico late in the week. This will cause strong SE
to S winds to develop in the waters W of 75W on Friday night.

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

$$
MT
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