[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121745
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU FEB 12 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1615 UTC.

...THE ITCZ...

ITCZ IS CENTERED ALONG 6N10W 3N20W 1N30W CROSSING THE EQUATOR
NEAR 39W AND INTO NE BRAZIL NEAR 3S45W.A SMALL CLUSTER OF
MODERATE CONVECTION IS OFF THE AFRICAN COAST FROM 5N-6N E OF
12W. SCATTERED MODERATE CONVECTION IS FROM 3S-3N BETWEEN 20W-34W.

...DISCUSSION...

GULF OF MEXICO...
STRONG UPPER-LEVEL WESTERLIES COVER THE GULF REGION AT THE BASE
OF A DEEP LAYER TROUGH OVER THE CONUS. THIS TROUGH CONTINUES TO
SUPPORT A COLD FRONT THAT...AS OF 1500 UTC...STRETCHES ACROSS
FLORIDA AND ENTERS THE REGION JUST NORTH OF TAMPA BAY AND
EXTENDS TO NEAR 27N86W WHERE IT BECOMES STATIONARY AND CONTINUES
ALONG 25N90W 23N95W TO THE SOUTHERN BAY OF CAMPECHE AND INLAND
OVER MEXICO. MULTI-LEVEL CLOUDS AND SCATTERED SHOWERS ARE WITHIN
80 NM OF THE BOUNDARY. N-NE WINDS AND A RELATIVELY COOLER AND
DRIER AIRMASS ARE OBSERVED N OF THIS FRONT. STRONG NW-N WINDS
ARE OBSERVED IN THE BAY OF CAMPECHE W OF THE FRONT. A SFC
TROUGH...A REFLECTION OF AN UPPER-LEVEL SHORT-WAVE...IS AHEAD OF
THE FRONT FROM 25N90W ALONG 21N93W TO 18N93W. UPPER LEVEL
SUBSIDENCE AND DRY AIR ARE MAINTAINING MOSTLY CLEAR CONDITIONS
IN THE SE GULF AWAY FROM THE INFLUENCE OF THE FRONTAL BOUNDARY.

CARIBBEAN SEA...
GENERALLY FAIR WEATHER IS PRESENT ACROSS THE WRN CARIBBEAN...
WHERE DEEP LAYER DRY AIR AND CONFLUENT WESTERLY FLOW ARE
OBSERVED. ISOLATED SHOWERS CONTINUE TO BE TRANSPORTED ACROSS THE
EASTERN CARIBBEAN BY STRONG TRADE WIND FLOW. THE TRADE WINDS ARE
EXPECTED TO WEAKEN OVER THE NEXT 24-48 HOURS AS HIGH PRESSURE
OVER IN THE W ATLC SHIFTS SE.

ATLANTIC OCEAN...
A COLD FRONT NICKS THE NW CORNER OF THE DISCUSSION AREA. AS OF
1500 UTC...THE FRONT ENTERS THE W ATLC NEAR 31N77W AND EXTENDS
SW CROSSING FLORIDA NEAR DAYTONA BEACH. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE WITHIN 50 NM OF THE BOUNDARY. SW
WINDS 20-25 KT AHEAD OF THE FRONT SHIFT TO W-NW 15-20 KT BEHIND
THE BOUNDARY. FAIR WEATHER COVERS THE REMAINDER OF THE W ATLC
DUE TO A 1027 MB SFC HIGH PRESSURE CENTERED NEAR 27N89W. THIS
SYSTEM IS EXPECTED TO MOVE INTO THE CENTRAL ATLANTIC...ALLOWING
TRADE WIND FLOW TO DECREASE ACROSS THE CARIBBEAN. FARTHER
EAST... A SFC TROUGH EXTENDS FROM A COLD FRONT N OF THE AREA
ALONG 31N29W 27N32W 26N39W TO 23N42W. MULTI-LEVEL CLOUDS WITH
POSSIBLE EMBEDDED SHOWERS ARE WITHIN 40 NM OF THE TROUGH. THIS
FEATURE IS BEGINNING TO WEAKEN AS THE AFOREMENTIONED HIGH
PRESSURE SLIDES EASTWARD. IN THE TROPICS...AN UPPER HIGH IS
PRESENT NEAR 6N33W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS
HIGH IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
WADDINGTON





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