[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071202
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
802 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 0600 UTC surface analysis and satellite imagery through
1145 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. Scatterometer data has
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 by 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 19N37W
to 08N41W, 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 14N between 36W and 44W.

A tropical wave in the equatorial central Atlantic extends from
02N-14N along 52W, 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 showers
convection mainly S of 08N.

A tropical wave axis in the central Caribbean extends south of
22N along 74W, 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 84W, moving W at 10-15 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 between 80W-85W.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the eastern Atlantic near 20N17W and
extends southwestward to 13N25W then westward to 18N39W. The ITCZ
begins W of a tropical wave near 10N41W and continues to 06N51W,
then resumes near 08N53W to 09N61W. Aside from the convection
related to the tropical waves, scattered moderate convection is
observed along the ITCZ between 40W-50W.

...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/ERA
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