[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241140
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N10W 2N21W CROSSING THE EQUATOR
NEAR 28W EXTENDING TO 1S34W INTO NE BRAZIL NEAR 3S45W. SCATTERED
MODERATE CONVECTION IS S OF 2N BETWEEN 10W-13W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS S OF 3N BETWEEN 17W-28W.
SCATTERED MODERATE CONVECTION IS S OF 2N BETWEEN 34W-42W.

...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 N GULF. THE SUBSIDENCE IS ALSO BEING SUPPORTED
IN THE VICINITY OF A SURFACE RIDGE OVER THE NW GULF...WITH A
1027 MB SURFACE HIGH OVER E MEXICO NEAR 23N99W. ACROSS THE E
GULF...NE TO E SURFACE WINDS IN THE WAKE OF A SURFACE COLD FRONT
OVER THE W 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. THESE
WINDS ARE FORECAST TO DIMINISH BELOW GALE FORCE AT 25/0000 UTC.

CARIBBEAN SEA...
A DEEP LAYER TROUGH OVER THE W ATLC EXTENDS INTO THE NW
CARIBBEAN AND IS ASSOCIATED WITH A SURFACE COLD FRONT IN THE NW
CARIBBEAN THAT EXTENDS FROM 22N82W TO CENTRAL CUBA NEAR 22N80W.
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
THE SW 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 DEEP LAYER TROUGH OVER
THE W ATLC AND NW CARIBBEAN. 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 15N E OF 65W.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH OVER THE W ATLC IS ASSOCIATED WITH A SURFACE
COLD FRONT THAT EXTENDS FROM CENTRAL CUBA NEAR 22N80W TO 27N68W
TO 32N60W TO NE OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE IS
SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE THIS
FRONT. ACROSS LOCATIONS IN THE CENTRAL AND E ATLC THAT ARE SE OF
THIS FRONT...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE IS
SUPPORTING FAIR WEATHER CONDITIONS. HOWEVER...A DEEP LAYER
TROUGH IS PRESENT OVER THE E ATLC N OF 21N BETWEEN 16W-32W WITH
AN ASSOCIATED SURFACE COLD FRONT EXTENDING FROM 27N31W TO 29N26W
TO 32N24W TO N OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE AND
ATMOSPHERIC INSTABILITY ARE SUPPORTING NUMEROUS SHOWERS ALONG
AND WITHIN 90 NM E OF THIS COLD FRONT. A 1009 MB SURFACE LOW N
OF THE DISCUSSION AREA NEAR 36N27W IS ALSO ASSOCIATED WITH THE
DEEP LAYER TROUGH OVER THE E ATLC. THIS SURFACE LOW IS FORECAST
TO MOVE SOUTHWARD DURING THE NEXT DAY AND BE LOCATED NEAR 26N26W
AS A 1011 MB SURFACE LOW AT 25/0600 UTC. FARTHER TO THE E...
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 26N14W TO A
1010 MB SURFACE LOW N OF THE CANARY ISLANDS NEAR 31N15W TO
32N15W TO N OF THE DISCUSSION AREA. ACROSS THE TROPICAL
ATLC...AN UPPER RIDGE IS S OF 11N E OF 52W. UPPER LEVEL
DIVERGENCE ASSOCIATED WITH THIS UPPER LEVEL RIDGE IS ENHANCING
THE CONVECTION ASSOCIATED WITH THE ITCZ. THIS UPPER LEVEL
DIVERGENCE IS ALSO SUPPORTING SCATTERED SHOWERS S OF 4N BETWEEN
44W-51W.

$$
COHEN




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