000 AXNT20 KNHC 301043 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT MON APR 30 2012 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 08N13W TO 06N17W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N17W TO 03N26W TO 03N37W TO THE EQUATOR NEAR 50W. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 07N BETWEEN 23W-39W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH EXTENDS OVER THE EASTERN GULF FROM 29N83W SOUTH-SOUTHEASTWARD OVER THE FLORIDA STRAITS TO EASTERN CUBA NEAR 20N76W. WHILE MOST OF THE ACTIVE WEATHER ASSOCIATED WITH THIS TROUGH CONTINUES TO BE ACROSS THE FLORIDA PENINSULA AND THE SW NORTH ATLC...A FEW WIDELY SCATTERED SHOWERS ARE OCCURRING OVER THE FLORIDA STRAITS AND IN THE VICINITY OF THE FLORIDA KEYS S OF 25N E OF 83W. THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF WEST-NORTHWESTERLY FLOW ALOFT WITH MOSTLY DRY AIR AND SUBSIDENCE NOTED ON WATER VAPOR IMAGERY BETWEEN 83W-89W. AT THE SURFACE...A WEAK SURFACE RIDGE AXIS EXTENDS FROM NORTHERN FLORIDA AND SOUTHERN GEORGIA NEAR 31N84W TO THE TEXAS GULF COAST NEAR 26N97W. EAST TO SOUTHEAST WINDS IN THE RANGE OF 10 TO 20 KT ARE EXPECTED THROUGH LATE MONDAY AS A WEAK SURFACE TROUGH... ANALYZED OVER THE FLORIDA STRAITS AND NW CARIBBEAN SEA MOVES WEST-NORTHWESTWARD OVER THE NEXT 24 TO 36 HOURS INTO THE CENTRAL GULF. WHILE THE ECMWF...NAM...AND UKMET HAVE BEEN CONSISTENTLY SUGGESTING THIS WEAK TROUGHING TO DRIFT WESTWARD...THE GFS HAS TRENDED LESS AGGRESSIVE WITH FORMING A SURFACE LOW OVER THE CENTRAL GULF ON MONDAY AND COME MORE INTO LINE WITH THE OTHER GLOBAL MODEL SOLUTIONS. THEREFORE...THE FORECAST CONTINUES TO INDICATE THIS TROUGHING WHICH IS EXPECTED TO DISSIPATE BY TUESDAY OVER THE NW GULF WATERS. CARIBBEAN SEA... A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE FLORIDA STRAITS THIS MORNING AND EXTENDS A TROUGH AXIS SOUTH-SOUTHEASTWARD TO EASTERN CUBA NEAR 20N76W. WATER VAPOR IMAGERY INDICATES A VERY DRY AIRMASS IS IN PLACE SOUTHWEST OF THIS UPPER LEVEL TROUGH AXIS AS WEST-NORTHWESTERLY CONFLUENT FLOW ALOFT DOMINATES N OF 14N W OF 76W. HOWEVER...AS A RESULT OF THE UPPER LEVEL TROUGH... A WEAK SURFACE TROUGH IS ANALYZED FROM THE FLORIDA STRAITS NEAR 24N81W ACROSS WESTERN CUBA TO 18N83W. A FEW ISOLATED LOW-TOPPED SHOWERS ARE OCCURRING IN THE VICINITY OF THE SURFACE TROUGH AXIS AND AREAS EAST FROM 17N-22N BETWEEN 75W-83W...INCLUDING JAMAICA AND EASTERN CUBA. THIS SURFACE TROUGH IS EXPECTED TO DRIFT WEST-NORTHWESTWARD OVER THE NEXT 24 TO 36 HOURS INTO THE CENTRAL GULF OF MEXICO. THE REMAINDER OF THE CARIBBEAN FALLS UNDER THE INFLUENCE OF SOUTHWEST TO WESTERLY UPPER LEVEL FLOW DUE TO AN ANTICYCLONIC CIRCULATION CENTERED OVER NE VENEZUELA NEAR 10N63W. MOST OF THE MIDDLE TO UPPER LEVEL MOISTURE ASSOCIATED WITH THIS RIDGE IS LOCATED ON THE NORTHWESTERN PERIPHERY THAT CONTINUES TO PROVIDE HIGH LEVEL CLOUDINESS E OF 73W. AT THE SURFACE... MODERATE TO FRESH EASTERLIES ARE NOTED ON RECENT OBSERVATIONS AND EARLIER ASCAT SCATTEROMETER PASSES WHICH ARE FORECAST TO PERSIST THROUGH WEDNESDAY. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL LOW AND ASSOCIATED TROUGH IS CENTERED OVER THE FLORIDA STRAITS AND IS PROVIDING MOST OF THE SW NORTH ATLC WITH PLENTY OF MOISTURE AND OVERCAST CLOUDINESS W OF 60W. INFRARED SATELLITE IMAGERY INDICATES THAT SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING OVER A LARGE AREA FROM 20N-30N BETWEEN 62W-81W. THE RIDGE AXIS OVER NORTHERN FLORIDA AND THE SW NORTH ATLC PRESENT YESTERDAY HAS SLOWLY ERODED AND SHIFTED EASTWARD AS A WEAK STATIONARY FRONT REMAINS ANALYZED TO THE NORTH OF THE DISCUSSION AREA ALONG 33N BETWEEN 68W AND THE SOUTH CAROLINA COAST. OTHERWISE...THE SW NORTH ATLC CONTINUES TO EXPERIENCE E-SE WINDS IN THE RANGE OF 10 TO 20 KT WITH POSSIBLE STRONGER WINDS S OF 27N W OF 70W DUE TO THE CLOSE PROXIMITY OF THE SURFACE TROUGH ACROSS THE FLORIDA STRAITS. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 27N39W AND CONTINUES TO PROVIDE SOUTHWESTERLY MIDDLE TO UPPER LEVEL FLOW WITH MOISTURE STREAMING NORTHEASTWARD FROM THE TROPICS TO THE NORTHEAST AFRICAN COAST. AT THE SURFACE HOWEVER...A SURFACE RIDGE HOLDS STRONG ANCHORED BY A 1031 MB HIGH CENTERED NW OF THE AZORES NEAR 43N33W. FRESH TO STRONG NE WINDS WERE NOTED ON EARLIER ASCAT PASSES OFF THE COAST OF WESTERN SAHARA STRETCHING TO THE NORTHERN CAPE VERDE ISLANDS TO 15N30W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN