000
AXNT20 KNHC 120533
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN APR 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0345 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N4W 2N10W 1N21W CROSSING THE 
EQUATOR NEAR 26W AND EXTENDING ALONG 2S31W AND INTO E BRAZIL 
NEAR 5S36W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION ARE FROM 4N TO THE EQUATOR BETWEEN 9W-18W. SMALL 
CLUSTERS OF SIMILAR CONVECTION ARE FROM 2N TO S OF THE EQUATOR 
BETWEEN THE PRIME MERIDIAN AND 8W AS WELL AS S OF THE EQUATOR 
BETWEEN 15W-26W.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH IS ALONG THE E U.S. SEABOARD AND CONTINUES 
TO SUPPORT A COLD FRONT THAT EXTENDS INTO THE W ATLC ACROSS 
FLORIDA NEAR JACKSONVILLE TO A WEAK 1015 MB LOW NEAR TALLAHASSEE 
AND THE FLORIDA BIG BEND REGION. AN EQUALLY WEAK COLD FRONT 
EXTENDS SW INTO THE GULF FROM THE SURFACE LOW ALONG 28N86 THEN W 
TO 28N90W WHERE THE FRONT STALLS AND CONTINUES AS A STATIONARY 
FRONT TO INLAND ACROSS EXTREME S TEXAS NEAR CORPUS CHRISTI. 
ISOLATED SHOWERS ARE WITHIN 60 NM N OF THE STATIONARY FRONT. S 
OF THE FRONTAL BOUNDARIES W OF 85W...SE TO ELY SURFACE FLOW OF 
UP TO 20 KTS AND GENERALLY FAIR WEATHER IS OBSERVED. THE SELY 
SURFACE RETURN FLOW IS FORECAST TO PERSIST AS THE NEXT AREA OF 
LOW PRESSURE HAS DEVELOPED OVER CENTRAL TEXAS AND WILL MOVE INTO 
THE NW GULF LATE MONDAY.

CARIBBEAN SEA...
EASTERLY TRADE WINDS UP TO 20 TO 30 KTS DOMINATE THE CARIBBEAN 
WITH SURFACE WIND CONVERGENCE CONTINUING IN THE SW CARIBBEAN 
GENERATING ISOLATED SHOWERS S OF 12N W OF 74W. STRONG SUBSIDENCE 
AND DRY AIR UNDER WEAK TROUGHING ACROSS THE BASIN IN THE MID AND 
UPPER LEVELS IS LIMITING AND PRECIPITATION TO ISOLATED SHALLOW 
LOW LEVEL MAINLY AFTERNOON SHOWERS THAT GENERATED OVER E CUBA 
AND HISPANIOLA MOVING INTO THE CARIBBEAN WATERS AD BEGINNING TO 
DISSIPATE. LITTLE CHANGE IS EXPECTED IN THE NEXT 24-48 HOURS.

ATLANTIC OCEAN...
A DEEP LAYERED TROUGH IS ALONG THE E U.S. SEABOARD EXTENDS INTO 
THE W ATLC AND SUPPORTING A COLD FRONT THAT ENTERS THE 
DISCUSSION AREA NEAR 32N74W CONTINUING W TO NEAR JACKSONVILLE 
FLORIDA. SHOWERS AND NUMEROUS THUNDERSTORMS AS INDICATED BY 
LIGHTENING DATA IS WITHIN ARE WITHIN 90 NM SW OF THE FRONT E OF 
78W. A PRE-FRONTAL SURFACE TROUGH INDICATED BY A WIND SHIFT 
EXTENDS FROM 29N79W TO OVER THE E COAST OF THE FLORIDA PENINSULA 
NEAR PALM BEACH WITH ISOLATED SHOWERS WITHIN 75 NM E OF THE 
TROUGH AXIS. FARTHER TO THE E ACROSS THE REMAINDER OF THE W 
ATLC...A MID TO UPPER LEVEL TROUGH WITH AXIS ALONG 65W TO S OF 
PUERTO RICO IS GENERATING CLUSTERS OF SCATTERED SHOWERS AND 
ISOLATED SHOWERS FROM 22N-32N BETWEEN 60W-70W. ACROSS THE 
CENTRAL AND E ATLC...AN ELONGATED UPPER TROUGH EXTENDS FROM NEAR 
26N25WNW TO 30N45W BUT IS NOT PRODUCING ANY SURFACE WEATHER. A 
LARGE SURFACE RIDGE DOMINATES THE SAME AREA ANCHORED BY A 1029 
MB HIGH CENTERED JUST S OF THE AZORES PROVIDING NE TO ELY 
SURFACE FLOW AND FAIR WEATHER ACROSS THE ATLC E OF 60W.

$$
WALLACE