[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240541
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST TUE FEB 24 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N9W 0N22W 1S33W 0N45W 2N50W.
SCATTERED MODERATE CONVECTION IS S OF 2N BETWEEN 17W-25W.
SCATTERED MODERATE CONVECTION IS ALSO S OF 2N BETWEEN 34W-38W.

...DISCUSSION...

GULF OF MEXICO...
GENERALLY FAIR WEATHER IS PRESENT ACROSS MUCH OF THE GULF
REGION...WHERE NORTHWESTERLY FLOW ALOFT IS SUPPORTING
ATMOSPHERIC SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS. DEEP
LAYER DRY AIR IS ALSO PRESENT ACROSS MUCH OF THE GULF REGION.
HOWEVER...UPPER LEVEL MOISTURE IS STREAMING SOUTHEASTWARD INTO
PORTIONS OF THE NW GULF. THE SUBSIDENCE IS ALSO BEING SUPPORTED
BY A 1030 MB SURFACE HIGH OVER E MISSISSIPPI NEAR 33N89W. ACROSS
THE E AND S GULF...NE TO E SURFACE WINDS IN THE WAKE OF A
SURFACE COLD FRONT OVER THE SW NORTH ATLC AND NW CARIBBEAN ARE
USHERING IN A RELATIVELY COOLER AND DRIER AIRMASS.
ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH
THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE
E PACIFIC REGION.

CARIBBEAN SEA...
A DEEP LAYER TROUGH OVER THE W ATLC EXTENDS INTO THE NW
CARIBBEAN AND IS ASSOCIATED WITH A SURFACE COLD FRONT THAT
EXTENDS FROM CENTRAL CUBA NEAR 22N79W TO THE NW CARIBBEAN NEAR
22N82W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS
WITHIN 60 NM EITHER SIDE OF THIS FRONT. ALSO...AN INCREASED
SURFACE PRESSURE GRADIENT IS RESULTING IN STRONG TRADE WINDS
ACROSS THE CARIBBEAN SEA...WITH NE TO E SURFACE WINDS OF 20 TO
30 KT ACROSS PORTIONS OF THE SW AND E CARIBBEAN. GENERALLY FAIR
WEATHER CONDITIONS ARE OCCURRING ACROSS MUCH OF THE CARIBBEAN
REGION...WHERE AN UPPER LEVEL RIDGE IS PRESENT TO THE SE OF THE
AFOREMENTIONED DEEP LAYER TROUGH. PATCHES OF LOW LEVEL MOISTURE
CONTINUE TO BE ADVECTED WESTWARD ACROSS THE CARIBBEAN BY THE
TRADE WINDS...WITH SCATTERED SHOWERS EMBEDDED WITHIN THESE
PATCHES OF LOW LEVEL MOISTURE. THE GREATEST CONCENTRATION OF
THESE SHOWERS IS S OF 17N BETWEEN 68W-73W.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH OVER THE W ATLC IS ASSOCIATED WITH A SURFACE
COLD FRONT THAT EXTENDS FROM CENTRAL CUBA NEAR 22N79W TO 27N70W
TO 32N62W TO NE OF THE DISCUSSION AREA...AND A DISSIPATING
SURFACE STATIONARY FRONT FROM 26N70W TO 28N66W TO 30N64W. LOW
LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM
EITHER SIDE OF EACH OF THESE FRONTS. ACROSS LOCATIONS IN THE
CENTRAL AND E ATLC THAT ARE SE OF THESE FRONTS...SUBSIDENCE
ASSOCIATED WITH A SURFACE RIDGE IS SUPPORTING FAIR WEATHER
CONDITIONS. HOWEVER...AN UPPER TROUGH IS PRESENT OVER THE E ATLC
WITH AN AXIS THAT EXTENDS FROM 20N30W TO 27N25W TO 32N24W TO N
OF THE DISCUSSION AREA. TO THE E OF THIS UPPER TROUGH
AXIS...UPPER LEVEL DIVERGENCE ASSOCIATED WITH AN UPPER LEVEL
WIND SPEED MAXIMUM IS SUPPORTING SCATTERED SHOWERS N OF 25N E OF
19W. THIS ACTIVITY IS BEING ENHANCED BY LOW LEVEL CONVERGENCE IN
THE VICINITY OF A SURFACE TROUGH THAT EXTENDS FROM 31N15W TO
32N14W TO NE OF THE DISCUSSION AREA. ACROSS THE TROPICAL
ATLC...AN UPPER RIDGE IS S OF 11N E OF 47W. UPPER LEVEL
DIVERGENCE ASSOCIATED WITH THIS UPPER LEVEL RIDGE IS ENHANCING
THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN




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