[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 070600
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 AM EDT Tue Aug 7 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 0000 UTC surface analysis and satellite imagery through
0530 UTC.

...SPECIAL FEATURES...

A gale warning is in effect for the south-central Caribbean. A
strong Atlantic ridge west of 60W is tightening the pressure
gradient in the south-central Caribbean. Wind gusts reaching
gale-force were expected tonight, and a scatterometer pass at
0130 UTC confirmed the existence of gale force winds in the Gulf
of Venezuela, and 30 kt winds along the coast of Colombia near
13N71W. Gale-force winds are forecast for the Gulf of Venezuela
on overnight and along the coast of Colombia Wed night. Please
see the Atlantic High Seas Forecast under AWIPS/WMO headers
MIAHSFAT2/FZNT02 KNHC for further details.

...TROPICAL WAVES...

A tropical wave axis in the eastern Atlantic extends from 20N36W
to 08N39W, moving W at 10-15 kt. Scatterometer data depicts a
distinct shift in wind direction along the convergence zone axis
west of the wave. The northern part of the wave is affected by
Saharan dry air intrusion, limiting convection to the area
south of 12N between 38W and 45W.

A tropical wave in the equatorial central Atlantic extends from
01N-14N along 50W, moving W at 10-15 kt. The wave continues to
be affected by intrusion of Saharan dry air and dust. Shallow
moisture in the vicinity of the ITCZ supports scattered moderate
convection mainly S of 10N.

A tropical wave axis in the central Caribbean extends south of
22N along 73W, moving W at 10-15 kt. The wave is in a moist
environment at the lower levels as indicated by LPW and water
vapor imagery, and under a diffluent environment between an
elongated upper-level low over the central basin and S-SW flow
to the east, which is supporting scattered showers N of 18N
between 70W-73W.

A tropical wave is in the western Caribbean with axis S of 21N
along 82W, moving W at 10 kt. LPW imagery shows shallow moisture
in the vicinity of the wave, and interaction with the monsoon
trough supports scattered moderate convection mainly S of 12N.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the eastern Atlantic near 20N16W and
extends southwestward to 13N28W then westward to 12N38W. The
ITCZ begins W of a tropical wave near 10N40W and continues to
06N49W, then resumes near 08N51W to 09N61W. Aside from the
convection related to the tropical waves, scattered moderate
convection is observed along the ITCZ.

...DISCUSSION...

GULF OF MEXICO...

A broad area of high pressure extends from the western Atlantic
into the northern Gulf. Scattered convection is observed just W
of the Florida peninsula, a remnant of evening thunderstorms
over land. Return flow associated with the surface ridge
continues to advect shallow moisture from the Caribbean into the
Gulf, supporting scattered moderate convection in the Yucatan
Channel and south-central Gulf waters between 84W-90W. A surface
trough is in the NE Gulf from the Florida Big Bend to 29N84W
with associated convection over land at this time.

Expect convection to fire up again across the basin later today.
A nocturnal thermal trough that will emerge off the Yucatan
Peninsula each night, and enhance the NE winds off the W Yucatan
Peninsula. Surface ridging will prevail elsewhere through Sat.

CARIBBEAN SEA...

Enhanced satellite imagery continues to show a thin layer of
Saharan dust moving across most of the basin where deep-layer
wind shear prevails. This environment continues to suppress the
development of significant convection across the basin. Shallow
moisture is present south of Cuba, supporting scattered showers.
The monsoon trough in the SW Caribbean supports convection near
Panama. Fresh to near-gale force winds in the south-central
Caribbean are forecast to increase to gale-force gusts in the
Gulf of Venezuela and off the coast of Colombia by tonight, then
sustained gale-force winds will develop through midweek. See the
Special Features section for further details.

ATLANTIC OCEAN...

Two tropical waves are moving across the basin. See above for
details. A subtropical low pressure system centered near 35N48W
interacting with a broad upper-level low has organized showers
and thunderstorms N of its center. Environmental conditions are
expected to be marginally conducive for it to acquire tropical
characteristics, and chances for tropical cyclone development
are low. A surface trough extends S and SE from it to 24N57W
supporting scattered showers and tstms N of 30N between 40W-50W.
Aside from the tropical waves, the remainder of the Atlc is
under the influence of surface high pressure that supports fair
weather.


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

$$
Mundell
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