000 AXNT20 KNHC 051746 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE APR 05 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ... ITCZ AXIS IS ALONG 06N10W 02N20W CROSSING THE EQUATOR NEAR 31W THEN INTO NE BRAZIL NEAR 02S45W. A STRONG LINE OF LOW-LEVEL CONVERGENCE SE OF THE ITCZ IN THE FORM OF A SQUALL LINE IS ANALYZED FROM 03N09W TO THE EQUATOR NEAR 07W THEN TO 02S04W. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 07N BETWEEN 05W-13W. ISOLATED MODERATE CONVECTION IS FROM THE EQUATOR TO 04N BETWEEN 18W-33W...AND FROM THE EQUATOR TO 02N BETWEEN 44W-50W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL TROUGH IS PROGRESSING ACROSS THE GULF THIS AFTERNOON AND SUPPORTS A COLD FRONT ANALYZED FROM THE FLORIDA BIG BEND NEAR 30N83W TO 24N90W TO THE COAST OF MEXICO NEAR 20N97W. A PRE-FRONTAL SURFACE TROUGH IS ALSO OVER THE SW GULF FROM THE COLD FRONT NEAR 24N90W TO 19N93W. THE SURFACE FRONT...ALONG WITH THE STRONG UPPER LEVEL DYNAMICS IS GENERATING NUMEROUS SHOWERS AND SCATTERED TSTMS FOCUSED ALONG AND BEHIND AN INTENSE SQUALL LINE OF SHOWERS AND TSTMS EXTENDING FROM FLAGLER BEACH SW TO THE TAMPA BAY REGION TO 26N87W. MOST OF THE CONVECTIVE ACTIVITY HOWEVER REMAINS WITHIN 180 NM SE OF THE COLD FRONT AND CONTINUES TO PUSH SOUTHEASTWARD ACROSS THE FLORIDA PENINSULA AND SE GULF WATERS. WEST OF THE FRONT...STRONG N-NE WINDS IN THE RANGE OF 20-30 KT ARE OCCURRING AS A RIDGE OF HIGH PRESSURE SETTLES IN OVER THE NW GULF WATER THROUGH THIS EVENING. THE RIDGE IS FORECAST TO SHIFT EASTWARD OVER THE NEXT 24 TO 36 HOURS WITH E-SE WINDS EARLY WEDNESDAY THEN SE RETURN FLOW BECOMING DOMINATE OVER THE WESTERN GULF THROUGH EARLY THURSDAY. CARIBBEAN SEA... THE CARIBBEAN SEA REMAINS UNDER MOSTLY SOUTHWESTERLY UPPER LEVEL FLOW BETWEEN AN UPPER LEVEL TROUGH OVER THE GULF OF MEXICO AND AN ANTICYCLONIC CIRCULATION CENTERED NEAR 11N59W PROVIDING MOSTLY DRY AIR AND SUBSIDENCE OVER MUCH OF THE EASTERN AND CENTRAL CARIBBEAN E OF 75W. WATER VAPOR IMAGERY INDICATES A STREAM OF MIDDLE TO UPPER LEVEL MOISTURE ON THE NORTHWESTERN PERIPHERY OF THE RIDGE EXTENDING FROM THE NW CARIBBEAN NEAR 18N82W ACROSS EASTERN CUBA AND OVER THE SW NORTH ATLC TO 24N65W. AT THE SURFACE...EASTERLY TRADES CONTINUE AND ARE EXPECTED TO PERSIST THROUGH THE REMAINDER OF THE WEEK DUE TO A FAIRLY STATIONARY RIDGE LOCATED IN THE SW NORTH ATLC. LOW-LEVEL MOISTURE CONTINUES TO ADVECT AROUND THE SOUTHWESTERN PERIPHERY OF THE ATLC RIDGE WITH ISOLATED SHOWERS OCCURRING MOSTLY OVER THE NE CARIBBEAN...AND PORTIONS OF PUERTO RICO...HISPANIOLA... AND FAR EASTERN CUBA. ALSO...LOW-LEVEL WIND SPEED CONVERGENCE ACROSS THE SW CARIBBEAN IS GENERATING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS S OF 12N W OF 78W. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH IS SWEEPING ACROSS THE EASTERN CONUS AND SUPPORTS A COLD FRONT ANALYZED FROM COASTAL SOUTH CAROLINA NEAR 34N79W TO THE FLORIDA COAST NEAR SAINT AUGUSTINE. A SQUALL LINE PRECEDES THE FRONT AND IS LOCATED FROM 32N78W TO COCOA BEACH FLORIDA. NUMEROUS SHOWERS AND SCATTERED TSTMS ARE OCCURRING BETWEEN THE SQUALL LINE AND THE COLD FRONT ACROSS THE SW NORTH ATLC WATERS AND PORTIONS OF THE FLORIDA PENINSULA THIS AFTERNOON. THE CONVECTIVE ACTIVITY IS FORECAST TO CONTINUE MOVING SOUTHEASTWARD THROUGH THE EVENING HOURS. THE COLD FRONT WILL CONTINUE MARCHING EASTWARD AND LOCATE N OF 20N BETWEEN 62W-74W BY WEDNESDAY AFTERNOON. HIGH PRESSURE IS EXPECTED TO BUILD IN BEHIND THE FRONT PROVIDING FOR STRONG N-NE WINDS WEST OF THE FRONT TO 80W THROUGH TOMORROW. FARTHER EAST...AN AMPLIFIED UPPER LEVEL TROUGH IS ALONG 36W WITH AN AXIS THROUGH 32N38W TO A BASE NEAR 25N50W. THIS UPPER LEVEL TROUGH SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N33W AND EXTENDS SW TO 24N46W...THEN BECOMES A SHEAR LINE WESTWARD TO 22N63W. A RECENT 05/1336 UTC ASCAT PASS DEPICTED STRONGER NE WINDS OF 20 KT WITHIN 120 NM NORTH OF THE BOUNDARY BETWEEN 46W-63W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE ANCHORED BY A 1027 MB HIGH CENTERED NEAR 34N56W N OF THE AFOREMENTIONED SHEAR LINE AND A 1021 MB HIGH CENTERED NEAR 28N28W EAST OF THE COLD FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN