000 AXNT20 KNHC 102341 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU MAY 10 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO 06N25W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N25W TO 03N34W TO THE EQUATOR NEAR 42W. SCATTERED MODERATE CONVECTION IS FROM 03N-06N BETWEEN 08W-13W. ISOLATED MODERATE CONVECTION IS FROM 04N-06N BETWEEN 22W-27W. ...DISCUSSION... GULF OF MEXICO... WESTERLY UPPER LEVEL FLOW IS OVER THE GULF THIS EVENING WITH WATER VAPOR IMAGERY INDICATING THAT DRY AND SUBSIDENCE PREVAILS N OF 24N E OF 90W. TO THE NORTHEAST...AN UPPER LEVEL TROUGH IS PROGRESSING EASTWARD OVER THE EASTERN CONUS AND SUPPORTS A COLD FRONT ANALYZED ACROSS THE SW NORTH ATLC TO THE SOUTHERN FLORIDA PENINSULA AND INTO THE EASTERN GULF ALONG 26N82W TO 26N85W. THE FRONT HAS BECOME VERY WEAK AND DIFFUSE OVER THE GULF WATERS... HOWEVER A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING OVER EASTERN PORTIONS OF THE SOUTHERN FLORIDA PENINSULA AS THE FRONT PUSHES EAST THIS EVENING. FARTHER WEST...AN UPPER LEVEL LOW IS CENTERED OVER FAR WEST TEXAS NEAR 31N104W AND SUPPORTS A DEVELOPING AREA OF LOW PRESSURE ACROSS SOUTH-CENTRAL TEXAS. WHILE NO FRONTAL BOUNDARIES ARE IDENTIFIED OVER INLAND TEXAS...MIDDLE TO UPPER LEVEL DIFFLUENCE IS MAXIMIZED OVER EASTERN TEXAS AND IS GENERATING SCATTERED SHOWERS AND TSTMS MAINLY INLAND W OF 96W...HOWEVER A FEW ISOLATED TSTMS ARE OCCURRING OVER THE NW GULF WATERS N OF 27N W OF 94W. OTHERWISE...THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A SURFACE RIDGE EXTENDING FROM A 1018 MB HIGH CENTERED OVER LAKE MICHIGAN SOUTHWARD TO 25N ALONG 90W. WEAK ANTICYCLONIC WINDS ARE EXPECTED THROUGH THE OVERNIGHT HOURS ACROSS THE EASTERN GULF E OF 90W...WHILE EAST-SOUTHEASTERLY FLOW IN THE RANGE OF 10 TO 15 KT PREVAILS W OF 90W AND IS FORECAST TO GRADUALLY INCREASE AND SPREAD EASTWARD FRIDAY INTO SATURDAY AS THE RIDGE SHIFTS EAST. CARIBBEAN SEA... AN UPPER LEVEL TROUGH IS OVER THE EASTERN CARIBBEAN WITH AXIS EXTENDING FROM THE SW NORTH ATLC NEAR 23N64W TO A BASE OVER NW VENEZUELA NEAR 11N70W. WEST OF THE TROUGH AXIS...DRY AND STABLE NW FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY WITH CLEAR SKIES AND FAIR CONDITIONS W OF 70W THIS EVENING. EAST OF THE TROUGH AXIS...MOIST SOUTHWESTERLY FLOW DOMINATES WITH MIDDLE TO UPPER LEVEL MOISTURE ADVECTING NORTHEASTWARD FROM THE EASTERN CARIBBEAN INTO THE CENTRAL ATLC. WHILE SURFACE TROUGHING HAS WEAKENED AND DISSIPATED...AMPLE MIDDLE TO UPPER LEVEL DIFFLUENCE IS MAXIMIZED EAST OF THE TROUGH AXIS AND IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS E OF 69W. SEVERAL OF THE LESSER ANTILLES ISLANDS HAVE REPORTED MORE THAN A TRACE OF PRECIPITATION THROUGHOUT THE LAST 24 HOURS WITH BARBADOS REPORTING 0.43 INCHES AND TRINIDAD REPORTING 1.02 INCHES AS OF 10/1200 UTC. THE UPPER LEVEL TROUGHING IS FORECAST TO GRADUALLY WEAKEN AND LIFT NORTHEASTWARD HOWEVER IT IS FORECAST TO BE REPLACED BY UPPER LEVEL TROUGHING MOVING OFF THE EASTERN CONUS. AS A RESULT...INCREASED PROBABILITY OF PRECIPITATION IS EXPECTED ACROSS THE EASTERN CARIBBEAN THROUGH LATE FRIDAY INTO SATURDAY. ATLANTIC OCEAN... WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL TROUGH EXTENDS OVER THE EASTERN CONUS WITH AXIS EXTENDING FROM WESTERN QUEBEC SOUTHWARD OVER THE DELMARVA REGION TO A BASE NEAR 30N78W OVER THE SW NORTH ATLC. THIS TROUGHING SUPPORTS A COLD FRONT ANALYZED FROM 32N74W TO 28N78W TO THE SOUTHERN FLORIDA PENINSULA COAST NEAR 27N80W. LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE FRONT AND MIDDLE TO UPPER LEVEL DIFFLUENCE LOCATED EAST OF THE TROUGH AXIS ARE GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE AREA FROM 24N-32N W OF 68W TO THE FRONT. THE FRONT IS FORECAST TO MOVE EAST OF 65W AND INTO THE CENTRAL ATLC BY LATE SUNDAY. FARTHER EAST OVER THE CENTRAL ATLC...A SURFACE RIDGE CONTINUES TO INFLUENCE THE AREA N OF 24N BETWEEN 38W-63W ANCHORED BY A 1031 MB HIGH CENTERED WELL NORTH OF THE REGION NEAR 44N43W. OVER THE EASTERN ATLC HOWEVER...AN UPPER LEVEL TROUGH DOMINATES E OF 38W AND SUPPORTS A 1007 MB LOW CENTERED SOUTH OF THE AZORES NEAR 37N28W. A SURFACE TROUGH IS ANALYZED FROM SOUTH OF THE LOW NEAR 33N28W TO 29N30W TO 25N39W. WHILE PRECIPITATION IS LIMITED WITH THIS SURFACE TROUGH...EARLIER ASCAT PASSES INDICATED THE PRESENCE OF THE TROUGH WITH STRONGER NORTHERLY WINDS IN WAKE OF ITS PASSAGE. FINALLY...A LARGE AREA OF SAHARAN DUST COVERS A LARGE PORTION OF THE TROPICAL EASTERN ATLC BOUNDED BY 27N13W TO 17N53W TO 07N50W TO 08N28W TO 10N14W. MUCH OF THIS AREA ON SATELLITE IMAGERY IS UNDER CLEAR SKIES AND STABLE CONDITIONS DUE TO THE SUSPENDED DUST. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN