000
AXNT20 KNHC 312339
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
805 PM EDT THU MAR 31 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 2330 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE COAST OF LIBERIA NEAR 5N10W 
CONTINUING SW ALONG 2N20W EQ30W 1S40W INTO NE BRAZIL NEAR 2S47W. 
ISOLATED WEAK TO MODERATE CONVECTION IS FROM 4S-4N BETWEEN 
12W-28W. SIMILAR ACTIVITY IS OCCURRING WITHIN 190 NM OFF THE 
COAST OF BRAZIL BETWEEN 40W-50W.

...DISCUSSION...

THE GULF OF MEXICO...
A BROAD UPPER LEVEL TROUGH MOVES ACROSS THE EASTERN HALF OF THE 
CONUS. A LONGWAVE IS EMBEDDED IN THE SOUTHERN PERIPHERY OF THE 
UPPER TROUGH MOVING ACROSS THE NORTHERN GULF. THIS SYSTEM 
SUPPORTS A COLD FRONT EXTENDING SW ACROSS NORTHERN FLORIDA. 
CONSEQUENTLY....THIS FRONT ENTERS THE GULF WATERS THROUGH TAMPA 
BAY AND CONTINUES SW ALONG 24N90W...BECOMING WEAK NEAR 22N92W 
INTO THE BAY OF CAMPECHE NEAR 19N94W. DESPITE THE EXTENSION OF 
THE FRONTAL SYSTEM...MOST OF THE INSTABILITY AND LOW-LEVEL 
CONVERGENCE IS FOCUSED ALONG A LINE OF STRONG CONVECTION 
DEPICTED ON DOPPLER RADAR IMAGERY E OF 85W FROM 25N-28N. 
NUMEROUS HEAVY SHOWERS AND THUNDERSTORMS ARE PRODUCING STRONG 
GUSTY WINDS AND POSSIBLE HAIL WITHIN THIS AREA...AFFECTING THE 
COASTAL WATERS FROM TAMPA BAY TO CAPE CORAL. THIS FRONT WILL 
CONTINUE TO DRIFT ESE OVER THE NEXT 24 HOURS. HOWEVER....THE 
CONVECTION IS EXPECTED TO WEAKEN DURING THIS TIME PERIOD.

THE CARIBBEAN SEA...
WATER VAPOR IMAGERY SHOWS VERY DRY AIR AND STRONG SUBSIDENCE 
ALOFT ACROSS THE CARIBBEAN SEA THIS EVENING. AT SURFACE...FRESH 
TO STRONG TRADE WINDS PERSIST WITH VERY FEW AREAS OF SHOWER 
ACTIVITY. THE FLOW TURNS SE W OF 75W N OF 15N AS SURFACE 
PRESSURE TENDENCIES DECREASE IN THE FAR EAST GULF OF MEXICO AND 
FLORIDA PENINSULA. THE FLOW ALSO TURNS CYCLONIC OVER THE FAR SW 
BASIN S OF 15N W OF 75W...GENERATING SCATTERED SHOWERS ALONG THE 
COAST OF COLOMBIA AND PANAMA BETWEEN 73W-79W. FRESH TRADE WINDS 
ARE EXPECTED TO PERSIST OVER E CARIBBEAN THROUGH SAT. THEN...THE 
WILL INCREASE ACROSS CARIBBEAN SUN AND MON AS HIGH PRESSURE 
BUILDS NE OF AREA.

THE ATLANTIC OCEAN...
A BROAD UPPER LEVEL TROUGH IS OVER THE EASTERN HALF OF THE CONUS 
SLOWLY MOVING OFF THE SEABOARD. THIS FEATURE SUPPORTS A COMPLEX 
SYSTEM OF FRONTAL BOUNDARIES AND LOW PRESSURE CENTERS OVER THE 
WEST ATLC N OF THE DISCUSSION AREA. HOWEVER...A SQUALL LINE IS 
MOVING OFF THE FLORIDA PENINSULA GENERATING NUMEROUS HEAVY 
SHOWERS AND THUNDERSTORMS ALONG WITH STRONG GUSTY WINDS AND 
POSSIBLE HAIL WITHIN AN AREA N OF 27N W OF 77W. THE COLD FRONT 
BEHIND THE SQUALL LINE IS EXPECTED TO ENTER THE WEST ATLC WATERS 
WITH CONVECTION IN THE NEXT 6 TO 12 HOURS. THE REMAINDER OF THE 
OCEAN IS DOMINATED BY A BROAD UPPER RIDGE COVERING MOST OF THE 
CENTRAL AND EAST ATLC. THE UPPER RIDGE SUPPORTS A PAIR OF 1022 
MB AND 1024 MB HIGHS NEAR 29N48W AND 26N33W RESPECTIVELY. 
HOWEVER...THE SOUTHERN EXTENSION OF A COLD FRONT CUTS IN BETWEEN 
THESE TWO HIGHS FROM 32N34W TO 28N43W. WEAK ISOLATED SHOWERS ARE 
WITHIN 50 NM AHEAD OF THE FRONT. THIS FRONT IS EXPECTED TO 
WEAKEN OVER THE NEXT 24 HOURS.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$

GARCIA