000
AXNT20 KNHC 121020
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N4W 2N12W 1N21W CROSSING THE 
EQUATOR NEAR 28W AND EXTENDING INTO E BRAZIL NEAR 4S40W. 
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE 
FROM 4N TO S OF THE EQUATOR BETWEEN 4W-16W. SCATTERED 
MODERATE/STRONG CONVECTION IS WITHIN 90/120 NM ALONG THE COAST 
OF BRAZIL S OF THE EQUATOR BETWEEN 39W-46W. CLUSTERS OF 
SCATTERED MODERATE CONVECTION ARE FROM 3N TO S OF THE EQUATOR 
BETWEEN 24W-34W. 

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH IS MOVING OFF THE E U.S. SEABOARD AND 
CONTINUES TO SUPPORT A COLD FRONT THAT EXTENDS INTO THE W ATLC 
ACROSS FLORIDA S OF JACKSONVILLE BECOMING STATIONARY INTO THE 
GULF ALONG 29N84W TO 29N89W DISSIPATING OVER THE NW GULF NEAR 
28N95W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS 
ARE ACROSS THE NW GULF N OF 27N W OF 93W AHEAD OF THE NEXT 
FRONTAL SYSTEM THAT IS WELL INLAND OVER CENTRAL TEXAS. THE GULF 
WATERS HAVE BECOME TRANQUIL WITH E TO SE SURFACE FLOW. THE NEXT 
FRONTAL BOUNDARY WILL MOVE INTO THE NW GULF LATE MONDAY.

CARIBBEAN SEA...
MODERATE/STRONG EASTERLY TRADE WINDS CONTINUE TO DOMINATE THE 
CARIBBEAN WITH SURFACE WIND CONVERGENCE IN THE SW CARIBBEAN 
GENERATING ISOLATED SHOWERS S OF 12N W OF 76W AND BANKING LOW 
LEVEL CLOUDS ALONG THE MOUNTAINS OF COSTA RICA. STRONG 
SUBSIDENCE AND DRY AIR UNDER WEAK TROUGHING ACROSS THE BASIN AT 
THE MID AND UPPER LEVELS ARE LIMITING PRECIPITATION TO 
PERSISTENT ISOLATED LOW LEVEL SHOWERS THAT GENERATED OVER 
HISPANIOLA YESTERDAY EVENING MOVING INTO THE CARIBBEAN WATERS 
JUST S OF HAITI. LITTLE CHANGE IS EXPECTED IN THE NEXT 24-48 
HOURS.

ATLANTIC OCEAN...
A DEEP LAYERED TROUGH IS MOVING OFF THE E U.S. SEABOARD EXTENDS 
INTO THE W ATLC AND SUPPORTING A COLD FRONT THAT ENTERS THE 
DISCUSSION AREA NEAR 32N71W CONTINUING W TO JUST S OF 
JACKSONVILLE FLORIDA. NUMEROUS SHOWERS AND THUNDERSTORMS AS 
INDICATED BY LIGHTENING DATA ARE WITHIN 90/120 NM SW OF THE 
FRONT E OF 75W. FARTHER TO THE E ACROSS THE REMAINDER OF THE W 
ATLC...A MID TO UPPER LEVEL SHORTWAVE TROUGH WITH AXIS ALONG 64W 
TO S OF PUERTO RICO IS GENERATING CLUSTERS OF SCATTERED SHOWERS 
AND ISOLATED SHOWERS FROM 24N-31N BETWEEN 60W-70W. ACROSS THE 
CENTRAL AND E ATLC...AN ELONGATED UPPER TROUGH EXTENDS FROM NEAR 
23N29W NW 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