000 AXNT20 KNHC 121058 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE APR 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...ITCZ... ITCZ AXIS IS ANALYZED ALONG 06N10W 02N22W CROSSING THE EQUATOR NEAR 26W THEN TO 04S30W AND INTO NE BRAZIL NEAR 05S38W. WIDELY SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 01N-05N BETWEEN 14W-29W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL TROUGH CONTINUES TO PROGRESS ACROSS THE SE CONUS THIS MORNING SUPPORTING A COLD FRONT THAT AT 12/0900 UTC ENTERS THE GULF OF MEXICO NEAR 30N87W THEN SW ALONG 28N90W TO 25N95W THEN INLAND ACROSS THE SOUTHERN MEXICO GULF COAST NEAR 20N96W. WATER VAPOR IMAGERY INDICATES FAIRLY DRY CONDITIONS AND OVERALL STRONG SUBSIDENCE ALOFT OVER MUCH OF THE GULF SO CONVECTION WITH THE FRONT IS LIMITED TO A PRE-FRONTAL SURFACE TROUGH EXTENDING FROM THE FLORIDA PANHANDLE NEAR 30N85W TO 28N89W IMPACTING THE COASTAL WATERS WITH ISOLATED SHOWERS N OF 28N BETWEEN 83W-88W. ISOLATED LOW-TOPPED SHOWERS ARE ALSO POSSIBLE WITHIN 45 NM EITHER SIDE OF THE COLD FRONT. STRONGER NE WINDS TO 20 KT ON RECENT SHIP AND BUOY OBSERVATIONS ARE NOTED NW OF THE FRONT DUE TO AN INCREASED PRESSURE GRADIENT BETWEEN THE FRONTAL TROUGH AND A 1021 MB HIGH CENTERED OVER CENTRAL TEXAS NEAR ABILENE. THE HIGH IS FORECAST TO SHIFT EASTWARD THROUGH EARLY WEDNESDAY WITH AXIS ALONG 90W PROVIDING THE GULF WITH LIGHT ANTICYCLONIC WINDS AND GENERALLY FAIR CONDITIONS. CARIBBEAN SEA... DRY AIR AND STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY ACROSS MUCH OF THE WESTERN CARIBBEAN IN ASSOCIATION WITH BROAD MIDDLE TO UPPER LEVEL TROUGHING EXTENDING FROM THE SW NORTH ATLC REGION. THE UPPER LEVEL TROUGH AXIS EXTENDS FROM NORTH OF HISPANIOLA NEAR 20N70W TO PANAMA NEAR 08N78W. THIS VERY DRY AIR ALOFT IS SUPPORTIVE OF CLEAR SKIES W OF 70W AND IS EXPECTED TO REMAIN IN PLACE THROUGH THURSDAY AS THE UPPER LEVEL TROUGH MOVES LITTLE. THE HIGHER POTENTIAL CONVECTIVE WEATHER REMAINS EAST OF THE TROUGH AXIS ALONG 70W. E OF 70W...E-NE TRADES CONTINUE WITH A SURFACE TROUGH ANALYZED FROM 12N65W TO 18N63W N OF ANGUILLA. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING E OF A LINE FROM EASTERN PUERTO RICO NEAR 18N66W TO ARUBA NEAR 12N70W. THIS AREA IS FORECAST TO REMAIN NEARLY STATIONARY THROUGH EARLY WEDNESDAY AS A FRONTAL TROUGH TO THE NORTH OVER THE SW NORTH ATLC SHIFTS E-NE OVER THE NEXT 24 TO 36 HOURS. HIGH VALUES OF TOTAL PRECIPITABLE WATER ARE NOTED OVER THE SE CARIBBEAN COINCIDING WITH THE SURFACE TROUGH AND THIS ADDED LOW-LEVEL MOISTURE WILL CONTINUE TO SUPPORT SCATTERED SHOWER ACTIVITY E OF 70W OVER THE NEXT COUPLE OF DAYS. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL TROUGH IS OVER THE CENTRAL ATLC THAT SUPPORTS A COLD FRONT ENTERING THE DISCUSSION AREA NEAR 32N44W EXTENDING SW AS A DISSIPATING STATIONARY FRONT TO 25N62W. A PRE-FRONTAL TROUGH IS ANALYZED FROM THE FRONT NEAR 29N50W TO 22N56W. WHILE MOST OF THE LOW-LEVEL CONVERGENCE IN THE VICINITY OF THE BOUNDARIES W OF 50W REMAINS WEAK...THE STRONGEST UPPER LEVEL DYNAMICS EVIDENT ON WATER VAPOR IMAGERY N OF 26N E OF 50W CONTINUE TO SUPPORT SCATTERED SHOWERS AND ISOLATED TSTMS FROM 27N TO BEYOND 32N BETWEEN 41W-48W. SW OF THE FRONT...A WEAK 1015 MB LOW IS CENTERED NEAR 22N62W WITH VERY LITTLE ASSOCIATED SHOWER ACTIVITY. MOST CLOUDINESS AND POSSIBLE ISOLATED SHOWERS FROM 10N-23N BETWEEN 52W-63W ARE ADVECTING NORTHEASTWARD FROM THE EASTERN CARIBBEAN SEA DUE TO A STRONG UPPER LEVEL TROUGH ALONG 70W S OF 24N. THE REMAINDER OF THE ATLC E OF 42W IS UNDER THE INFLUENCE OF A SURFACE RIDGE WITH AXIS EXTENDING FROM THE AZORES NEAR 38N27W TO 25N42W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN