[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 300558
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1258 AM EST Thu Nov 30 2017

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
0515 UTC.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 10N14W to
09N18W. The Intertropical Convergence Zone extends from 09N18W to
02N51W. Scattered moderate convection is from 04N-09N between
29W-38W.

...DISCUSSION...

GULF OF MEXICO...

A broad mid to upper-level ridge is over much of the Gulf basin
with a mid to upper-level shortwave trough progressing eastward
over the Ohio River valley. A 1018 mb low is centered across
northwest Arkansas with the associated cold front extending
southward to Louisiana and the northwest Gulf waters along 94W and
north of 28N. The front continues to weaken as the mid-level
energy progresses eastward. A surface trough extends from the cold
front near 29N93W to 25N91W. While water vapor imagery indicates
very dry conditions aloft, shallow low-level moisture in the
vicinity of the trough is supporting isolated showers within 90 nm
either side of the boundary. Moderate east winds prevail east of
the surface trough and generally gentle to moderate northerly
winds prevail west of the trough. Another trough extends across
the northern portion of the Yucatan Peninsula and continues over
the west Caribbean. Isolated showers are noted within 50 nm north
of this trough affecting the Yucatan Channel. The trough over the
northwest waters is forecast become diffuse by early Sunday with
ridging anchored across the eastern CONUS influencing the basin
with gentle to moderate easterly winds. Little change is expected
elsewhere.

CARIBBEAN SEA...

West-northwesterly flow aloft prevails over much of the basin on
the northern periphery of an upper-level anticyclonic circulation
anchored in the East Pacific waters south of Panama near 05N84W.
Generally dry air aloft and overall stable conditions are noted
across the central and eastern Caribbean, with most atmospheric
moisture centered around Panama. This convection is due to the
presence of the monsoon trough along 10N and enhanced due to
favorable upper-level divergence. A surface trough extends from
the northern Yucatan Channel to 14N82W with isolated showers.
Farther east, the only other area of note is a surface trough
analyzed southeast of Trinidad and Tobago from 13N58W to 10N60W.
Scattered showers are occurring within 150 nm either side of the
boundary impacting eastern Venezuela, Trinidad and Tobago, and
Barbados overnight. Moderate to fresh trades will persist east of
80W into Thursday, with slightly strong winds anticipated within
120 nm of the Colombia coast through the overnight hours.

...HISPANIOLA...

Clear skies and fair weather conditions are across the island
as the influence of dry westerly flow aloft remains in place over
the region. Little change is expected through Friday.

ATLANTIC OCEAN...

A mid to upper-level shortwave trough is noted over the west
Atlantic that supports a 1014 mb surface low centered near 24N73W.
A surface trough extends from 28N70W to the low to 21N75W.  Low-
level moisture convergence along with mid to upper-level
divergence east of the low/trough is supporting scattered moderate
convection occurring north of 22N between 64W-70W. The low is
expected to move northeast into the central Atlantic waters
during the next 24 hours. Farther east, a vigorous mid to upper-
level low is centered over the central Atlantic supports a storm-
force 985 mb low nearly centered north of the discussion area near
39N40W. The associated cold front enters the discussion area near
31N36W to 28N43W to 29N54W. Isolated showers are possible within
90 nm on either side of the front. To the southeast, a surface
trough extends from 28N34W to 24N47W. The remainder of the
central and eastern Atlantic is under the influence of rather
benign and tranquil conditions south of 25N.

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

$$

ERA
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