000
AXNT20 KNHC 122336
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N9W 2N20W 1N30W CROSSING THE 
EQUATOR NEAR 35W AND EXTENDING INTO NE BRAZIL NEAR 3S40W. 
SCATTERED STRONG CONVECTION IS ACROSS LIBERIA AND THE WRN IVORY 
COAST FROM 4N-10N BETWEEN 5W-11W. ELSEWHERE...SCATTERED MODERATE 
CONVECTION IS S OF 2N BETWEEN 35W-46W. 

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH ACROSS THE SRN PLAINS SUPPORTS A 1005 MB 
SURFACE LOW CENTERED OVER NW LOUISIANA. THE ATTENDANT COLD FRONT 
ENTERS THE GULF NEAR THE TEXAS AND LOUISIANA BORDER EXTENDING 
ALONG 28N95W TO INLAND OVER NE MEXICO JUST S OF BROWNSVILLE 
TEXAS. LOW-LEVEL SURFACE CONVERGENCE ALONG WITH UPPER-LEVEL 
DIFFLUENCE E OF THE UPPER TROUGH IS GENERATING SCATTERED SHOWERS 
AND TSTMS ACROSS A MAJORITY OF ERN LOUISIANA...MISSISSIPPI AND 
WRN ALABAMA WHILE CONVECTIVE ACTIVITY REMAINS N OF 28N ACROSS 
THE NW AND MIDDLE GULF. A WEAK STATIONARY FRONT IS ACROSS THE NE 
GULF AND EXTENDS FROM TAMPA FLORIDA W-NW TO NEAR NEW ORLEANS 
LOUISIANA. SCATTERED SHOWERS ARE WITHIN 30 NM S OF THE 
STATIONARY FRONT AND ALSO NOTED N OF THE FRONT W OF 85W OVER THE 
NRN MIDDLE GULF. SLY SURFACE FLOW DOMINATES ACROSS THE SRN GULF 
AND WILL PRECEDE THE NEXT FRONTAL BOUNDARY FORECAST TO ENTER THE 
NW GULF LATE MONDAY.

CARIBBEAN SEA...
MODERATE/STRONG EASTERLY TRADE WINDS CONTINUE TO DOMINATE ACROSS 
THE CARIBBEAN SEA. STRONG SUBSIDENCE AND DRY AIR UNDER WEAK 
TROUGHING ACROSS THE BASIN AT THE MID AND UPPER LEVELS ARE 
LIMITING PRECIPITATION TO ISOLATED LOW-LEVEL SHOWERS OVER THE 
LESSER ANTILLES AND PORTIONS OF PUERTO RICO AND HISPANIOLA. 
LITTLE CHANGE IS EXPECTED OVER THE NEXT 24-48 HOURS.

ATLANTIC OCEAN...
A DEEP LAYERED TROUGH ACROSS THE NW ATLC SUPPORTS A COLD FRONT 
THAT ENTERS THE DISCUSSION AREA NEAR 32N64W CONTINUING SW ALONG 
30N66W 27N70W OVER ABACO AND GRAND BAHAMA ISLANDS TO INLAND OVER 
THE SRN FLORIDA PENINSULA NEAR PALM BEACH. ISOLATED SHOWERS ARE 
WITHIN 90 NM E OF THE FRONT N OF 27N. NW OF THE COLD FRONT 
ACROSS THE REMAINDER OF THE W ATLC...A 1024 MB HIGH PRESSURE 
RIDGE CENTERED OVER ERN NORTH CAROLINA IS FORECAST TO PROVIDE 
FAIR WEATHER CONDITIONS THROUGH EARLY MONDAY. FARTHER TO THE 
E...A MID TO UPPER LEVEL SHORTWAVE TROUGH WITH AXIS ALONG 56W TO 
THE FAR NE CARIBBEAN IS GENERATING POSSIBLE SCATTERED SHOWERS 
FROM 18N-24N BETWEEN 50W-58W. THE REMAINDER OF THE CENTRAL AND 
ERN ATLC IS DOMINATED BY A LARGE SURFACE RIDGE ANCHORED BY A 
1034 MB HIGH CENTERED W OF THE AZORES NEAR 40N40W PROVIDING NE 
TO ELY SURFACE FLOW AND FAIR WEATHER ACROSS THE ATLC E OF 50W.

$$
HUFFMAN