[Tropical] Tropical Weather Discussion

[EMWIN Server]

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


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