000
AXNT20 KNHC 130545
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST FRI FEB 13 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 
0515 UTC.

...THE ITCZ...

ITCZ IS CENTERED ALONG 5N8W 2N20W CROSSING THE EQUATOR NEAR 31W 
AND INTO NE BRAZIL NEAR 4S39W. CLUSTERS OF SCATTERED MODERATE 
CONVECTION ARE WITHIN 60 NM ON EITHER SIDE OF THE AXIS BETWEEN 
12W-21W.
 
...DISCUSSION...

GULF OF MEXICO...
A PROGRESSIVE MID LATITUDE PATTERN WITH STRONG MIDDLE TO 
UPPER-LEVEL WESTERLIES COVERS THE GULF REGION BETWEEN THE SRN 
EDGE OF A DEEP LAYER TROUGH OVER THE CANADIAN MARITIMES AND THE 
RIDGE OVER CENTRAL AMERICA AND THE YUCATAN PENINSULA. A SURFACE 
COLD FRONT EXTENDS FROM THE W ATLC ACROSS CENTRAL FLORIDA INTO 
THE GULF NEAR ST. PETERSBURG W TO 27N86W. FROM THAT POINT A WARM 
FRONT EXTENDS SW TO 24N95W IN THE WRN GULF. MULTI-LEVEL CLOUDS 
AND ISOLATED SHOWERS ARE WITHIN 90 NM ON EITHER SIDE OF THE 
BOUNDARY ACROSS THE CENTRAL GULF. THE STRONG WESTERLY 
ANTICYCLONIC FLOW HAS PREVENTED THE DEVELOPMENT OF AND DEEP 
CONVECTION ACROSS THE BASIN THIS EVENING. ELY WINDS AND A 
RELATIVELY DRIER AIRMASS ARE OBSERVED N OF THIS FRONT AND 
SOUTHERLY FLOW IS DOMINANT SE OF THE WARM FRONT. UPPER LEVEL 
SUBSIDENCE AND DRY AIR ARE MAINTAINING MOSTLY CLEAR CONDITIONS 
IN THE SE AND SW GULF AWAY FROM THE INFLUENCE OF THE FRONTAL 
BOUNDARY.

CARIBBEAN SEA...
CONFLUENCE BETWEEN THE FLOW AROUND THE UPPER LEVEL RIDGE AXIS 
OVER CENTRAL AMERICA AND THE UPPER TROUGH OVER THE CENTRAL ATLC 
EXTENDING SW ACROSS THE ERN CARIBBEAN IS LIMITING ANY DEEP 
CONVECTION OVER MUCH OF THE CARIBBEAN. ISOLATED SHOWERS CONTINUE 
TO BE TRANSPORTED ACROSS THE CARIBBEAN BY STRONG TRADE WIND 
FLOW. MOST NOTABLY ACROSS THE NE CARIBBEAN AND WITHIN 90 NM OF 
A LINE FROM CARACAS VENEZUELA TO 17N81W IN THE NW CARIBBEAN.  
THE TRADE WINDS ARE FORECAST TO RELAX AND GRADUALLY WEAKEN OVER 
THE NEXT 24-48 HOURS AS HIGH PRESSURE IN THE CENTRAL ATLC NEAR 
24N56W SHIFTS EWD.

ATLANTIC OCEAN...
A SURFACE COLD FRONT ASSOCIATED WITH THE DEEP LAYER TROUGH OVER 
THE CANADIAN MARITIMES IS SLOWLY MOVING SE AND ENTERS THE 
DISCUSSION AREA NEAR 32N70W EXTENDING SW TO MELBOURNE FLORIDA 
AND INTO THE GULF OF MEXICO. SCATTERED SHOWERS ARE WITHIN 90 NM 
OF THE BOUNDARY. ELSEWHERE...FAIR WEATHER COVERS MUCH OF THE W 
ATLC WITH CONFLUENT UPPER FLOW FOUND BETWEEN THE COLD FRONT AND 
A 1025 MB SURFACE HIGH PRESSURE CENTERED NEAR 24N56W. THE HIGH 
PRESSURE IS EXPECTED TO WEAKEN AS IT MOVES EWD INTO THE CENTRAL 
ATLC...ALLOWING TRADE WIND FLOW TO DECREASE ACROSS THE WRN ATLC. 
FARTHER E...A SURFACE TROUGH EXTENDS FROM A COLD FRONT N OF THE 
AREA ALONG 31N25W TO 26N29W. A SECOND SURFACE TROUGH TO THE SW 
EXTENDS FROM 25N38W TO 19N42W. MULTI-LEVEL CLOUDS WITH POSSIBLE 
EMBEDDED SHOWERS ARE WITHIN 30 NM OF THE TROUGHS. HIGH CLOUDS 
ARE CENTERED FARTHER SE WHERE MID TO UPPER LEVEL MOISTURE IS 
BEING ADVECTED NEWD AHEAD OF AN UPPER LEVEL TROUGH OVER THE ERN 
ATLC. FARTHER S ACROSS THE TROPICAL ATLC...AN UPPER HIGH IS 
PRESENT NEAR 3N31W. UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THIS 
HIGH IS ENHANCING THE CONVECTION ALONG THE ITCZ.

$$
HUFFMAN