000
AXNT20 KNHC 111053
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT APR 11 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 7N8W 3N18W CROSSING THE EQUATOR NEAR 
23W AND EXTENDING INTO E BRAZIL NEAR 5S37W. SCATTERED/NUMEROUS 
STRONG CONVECTION IS WITHIN 90 NM OF LINE FROM 00N17W ACROSS THE 
ITCZ TO 3N21W. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION ARE FROM 1N-4N BETWEEN 10W-17W WITH LARGER 
CLUSTERS ALONG THE COAST OF SOUTH AMERICA S OF THE EQUATOR 
BETWEEN 39W-47W. 

...DISCUSSION...

GULF OF MEXICO...
THE VIGOROUS DEEP LAYERED TROUGH CONTINUES TO MOVE WITH THE 
UPPER LOW OVER VIRGINIA SUPPORTING A COLD FRONT THAT EXTENDS 
ACROSS THE CAROLINAS AND GEORGIA...SE LOUISIANA CONTINUING SW 
JUST OFF THE TEXAS GULF COAST THEN W INLAND S OF CORPUS CHRISTI 
ACROSS N MEXICO. SCATTERED SHOWERS ARE NOW ACROSS THE N GULF N 
OF 28N E OF 90W ACROSS NE FLORIDA AHEAD OF THE FRONT. THE FRONT 
WILL PROGRESS E INTO THE W ATLC DRAPING W ACROSS THE N GULF 
WATERS LATER TODAY EXTENDING FROM THE FLORIDA PANHANDLE TO S 
TEXAS AND THEN BEGIN TO STALL. SOUTHERLY RETURN FLOW REMAINS  
ACROSS A MAJORITY OF THE GULF WITH MOSTLY FAIR CONDITIONS OVER 
MOST OF THE GULF WITH THE EXCEPTION OF LOW LEVEL CLOUDS BEING 
BANKED W OF 95W TO INLAND OVER S TEXAS AND E MEXICO. AN UPPER 
LEVEL RIDGE WITH AXIS ALONG 96W IS PROVIDING THE GULF WITH W TO 
NW UPPER LEVEL FLOW BRINGING TROPICAL MOISTURE ACROSS MEXICO 
INTO THE NW GULF. 

CARIBBEAN SEA...
EASTERLY TRADE WINDS OF 20 TO 30 KTS DOMINATE THE CARIBBEAN AND 
THE NATURAL FLOW IN THE SW CARIBBEAN CONTINUE TO BANK LOW 
LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS S OF 13N BETWEEN 
76W-81W. STRONG SUBSIDENCE AND DRY AIR IN THE MID AND UPPER 
LEVELS LIMITING ANY ISOLATED SHOWERS TO THE LOWER LEVELS. LITTLE 
CHANGE IS EXPECTED IN THESE SURFACE WIND PATTERNS OVER THE NEXT 
24 HOURS. 

ATLANTIC OCEAN...
A LARGE SCALE MID/UPPER TROUGH OVER THE W/CENTRAL ATLC CONTINUES 
TO FLATTEN PROVIDING LIMITED SUPPORT FOR A SURFACE TROUGH 
EXTENDING FROM 32N50W TO 27N61W. ONLY BROKEN CLOUDINESS AND 
POSSIBLE LINGERING ISOLATED SHOWERS ARE WITHIN 60 NM OF THE 
SURFACE TROUGH. A SURFACE RIDGE EXTENDS W OF THE TROUGH FROM A 
WEAK 1025 MB HIGH E OF BERMUDA NEAR 32N60W ACROSS THE REMAINDER 
OF THE W ATLC INTO THE FAR E GULF OF MEXICO AND IS PROVIDING 
FAIR WEATHER AND A FEW PASSING HIGH LEVEL CLOUDS FROM 24N TO 
BEYOND 32N BETWEEN 36W-69W. WINDS ARE GENERALLY LIGHT ACROSS THE 
W ATLC BESIDES FOR SWLY WINDS OF UP TO 20 KT N OF 30N W OF 75W 
ENHANCED BY THE LOW PRESSURE AREA OVER THE E CONUS. FARTHER 
E...AN UPPER LOW IS ROUGHLY CENTERED NEAR 25N32W AND BECOMING 
ELONGATED E/W. AT THE SURFACE ACROSS THE REMAINDER OF THE 
CENTRAL AND THE ENTIRE E ATLC...A 1029 MB HIGH IS CENTERED JUST 
SW OF THE AZORES PROVIDING NE TO ELY SURFACE FLOW AND GENERALLY 
FAIR WEATHER. 

$$
WALLACE