[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120001
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
701 PM EST Sat Mar 11 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 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough axis extends from the African coast near
07N12W to 03N20W. The Intertropical Convergence Zone extends from
03N20W to the equator at 38W to the coast of South America near
02S45W. Scattered moderate convection is from 01N-05N between
14W-26W.

...DISCUSSION...

GULF OF MEXICO...

Water vapor imagery indicated a zonal pattern over the Gulf
characterized by a flat ridge with mean axis along 88W. Strong W
to WSW flow was noted over the basin with satellite derived winds
at jetstream level of 90-100 KT winds along the immediate Gulf
coast. The flow was becoming more diffluent over the western Gulf
in advance of a shortwave trough moving through central Texas. At
the surface a stationary front extended from near Fort Myers
Florida through 27.5N88W to the Louisiana-Texas border. This front
was in the process of dissipating as of 2100 UTC. A weak area of
low pressure of 1014 mb was noted along the Texas coast. Coastal
WSR-88D data and satellite imagery indicated scattered
thunderstorms were developing within 90-120 NM NE of the low with
an overall increase in lightning strikes over the past half hour.
E to SE return flow was increasing to 15-20 KT over the
northwestern Gulf in advance of the low pressure. The area of low
pressure is forecast to move NE to just south of the Louisiana
coast by early Sunday then stall in the north-central Gulf into
Sunday night while weakening. N to NE winds will increase in the
wake of the low over the NW Gulf to 20-30 KT early Sunday then
diminish slightly Sunday night.

CARIBBEAN SEA...

Broad anticyclonic flow prevailed over the entire Caribbean Sea
with strong subsidence noted over the area S of 18N. At the
surface a 1009 mb low is centered over northern Colombia near
10N73W. Retreating high pressure over the central Atlantic has
relaxed the pressure gradient such that moderate to fresh trade
winds were noted, generally in an area from the N coast of South
America to 18N between 65W and 75W. Strongest winds were occurring
along the north coast of Colombia, and in a belt from 16N to 18N
south of Hispaniola. Patches of broken to overcast low clouds with
embedded showers were noted over Puerto Rico, Hispaniola and
eastern Cuba. Little change in overall conditions are expected
over the next 24 hours.

...HISPANIOLA...

As noted above, broken to overcast low and mid clouds were noted
over the entire island with embedded scattered showers. The 1200
UTC Santo Domingo rawinsonde showed a fairly deep layer of
moisture, up to 600 mb with precipitable water values of 1.53
inches. This is somewhat wetter than normal for March. Expect
little change in these conditions over the next 24 hours.

ATLANTIC OCEAN...

A flat mid-to upper level trough is over the western Atlantic
W of 60W. A shortwave ridge was noted E of the trough N of 25N
along 45W with a downstream upper level low near 28N23W producing
scattered showers. A cold front over the Atlantic extends from
31N61W to 27N75W to the east coast of Florida near Palm Beach. The
front was becoming stationary west of 75W as of 2100 UTC.
Scattered showers are within 60-90 NM of the front. A 1030 mb high
is centered over the central Atlantic near 34N37W. A ridge axis
extends SW from the high through 29N45W to 25N64W. The cold front
is forecast to move east and extend from 31N54W to 26N60W to the
central Bahamas by late Sunday with only widely scattered showers
expected.


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

$$
Cobb
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