000 AXNT20 KNHC 252336 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU APR 25 2013 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 09N13W TO 03N24W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 03N24W TO THE EQUATOR NEAR 32W. SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN 90 NM OF THE EQUATOR AT 06W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM THE EQUATOR TO 04N BETWEEN 10W-25W. ...DISCUSSION... GULF OF MEXICO... WEST TO NORTHWESTERLY MID TO UPPER LEVEL FLOW IS NOTED OVER THE GULF THIS EVENING BETWEEN AN ANTICYCLONIC CIRCULATION CENTERED OVER THE EASTERN PACIFIC REGION NEAR 09N95W AND A PAIR OF MIDDLE TO UPPER LEVEL SHORTWAVE TROUGHS CENTERED OVER THE NE CONUS AND GREAT LAKES REGION. THE OVERALL BROAD TROUGHING OVER THE EASTERN U.S. SUPPORTS A STATIONARY FRONT EXTENDING ACROSS THE FLORIDA PANHANDLE JUST WEST OF APPALACHICOLA INTO THE GULF TO NEAR 27N90W THEN CONTINUES TO A 1021 MB LOW NEAR 25N96W THEN SOUTHWARD TO THE SOUTHERN BAY OF CAMPECHE NEAR 19N95W. WITH LITTLE UPPER LEVEL DYNAMIC SUPPORT REMAINING FOR THE STATIONARY FRONT...LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE BOUNDARY IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 26N-29N BETWEEN 88W-97W. LIGHTNING DATA INDICATED THAT THE MOST ACTIVE AREA OF THUNDERSTORMS WERE NOTED ABOUT 90 NM S OF GALVESTON TEXAS. THE FRONT WILL REMAIN DRAPED ACROSS THE GULF OVERNIGHT THEN GRADUALLY DISSIPATE DURING THE DAY ON FRIDAY AS EAST TO SOUTHEAST RETURN FLOW INCREASES ACROSS THE REGION. THIS GENERAL PATTERN IS EXPECTED TO PERSIST INTO THE WEEKEND. CARIBBEAN SEA... OVERALL DRY AND STABLE AIR IN NORTHWESTERLY FLOW ALOFT DOMINATES MUCH OF THE CARIBBEAN THIS EVENING RESULTING IN OVERALL BENIGN CONDITIONS ACROSS THE BASIN. SATELLITE AND TOTAL PRECIPITABLE WATER IMAGERY INDICATE INCREASED LOW-LEVEL MOISTURE AND ISOLATED SHOWERS OCCURRING OVER THE SE CARIBBEAN S OF 16N E OF 69W. OTHERWISE...TRADE WINDS REMAIN IN THE RANGE OF 10 TO 15 KT AS INDICATED BY AN EARLIER 1442 UTC ASCAT PASS. THESE WINDS ARE EXPECTED TO PERSIST IN THAT RANGE OVER THE NEXT SEVERAL DAYS. THE ONLY EXCEPTION EXPECTED WILL BE PERIODS OF SLIGHTLY HIGHER NE TRADES S OF 13N BETWEEN 72W-78W IN THE AREA OF CLOSE PROXIMITY TO THE COLOMBIA COAST. ATLANTIC OCEAN... NARROW MID TO UPPER LEVEL RIDGE IS OVER THE FAR WESTERN PORTION OF THE SW NORTH ATLANTIC WITH AXIS EXTENDING FROM THE FLORIDA STRAITS TO BEYOND 32N71W. A 1024 MB HIGH CENTERED NEAR 29N77W IS PROVIDING OVERALL FAIR CONDITIONS THIS EVENING W OF 70W...AN APPROACHING FRONTAL SYSTEM CURRENTLY ANALYZED INLAND ACROSS SOUTH CAROLINA AND GEORGIA IS EXPECTED TO MOVE OFF THE COAST LATER THIS EVENING INTO THE OVERNIGHT PERIOD. PRE-FRONTAL TROUGHING AND CONVERGENCE LINE IS GENERATING WIDELY SCATTERED SHOWERS WITHIN 45 NM EITHER SIDE OF A LINE FROM 34N75W TO 31N78W. FARTHER EAST...WATER VAPOR IMAGERY INDICATES A SMALL MID TO UPPER LEVEL LOW CENTERED NEAR 25N63W THAT IS PROVIDING SOME SUPPORT TO A SURFACE TROUGH EXTENDING FROM 30N66W TO 24N65W. A DISSIPATING STATIONARY FRONT EXTENDED FROM 32N68W TO 28N70W. ISOLATED SHOWERS ARE OCCURRING WITHIN 45 NM EITHER SIDE OF THE STATIONARY FRONT...WHILE SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 180 NM E OF THE SURFACE TROUGH S OF 27N AND ELSEWHERE FROM 21N TO 25N BETWEEN 58W AND 65W. THIS ACTIVITY IS LIKELY ENHANCED DUE TO THE AREA OF MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE EAST OF THE UPPER LEVEL LOW AND TROUGH AXIS. FINALLY...THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A LARGE PERSISTENT DEEP LAYERED LOW CENTERED NEAR 34N32W. THE SURFACE 998 MB LOW WAS CENTERED NEAR 34N31W WITH THE ASSOCIATED WEAKENING OCCLUSION WRAPPING AROUND THE LOW TO A TRIPLE POINT LOCATED NEAR THE AZORES NEAR 38N26W. THE WEAKENING COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N23W AND EXTENDS S- SW ALONG 26N25W TO 22N30W TO 19N38W. A SECONDARY FORMING FRONT ENTERED THE DISCUSSION AREA NEAR 32N29W TO 29N33W WHICH BECAME A TROUGH AND EXTENDED THROUGH 28N37W TO 29N43W. ISOLATED WARM- TOPPED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE WEAKENING FRONT...AND WITHIN 90 NM E OF THE NEW FRONT. BROAD FLAT ANTICYCLONIC FLOW PREVAILED OVER THE TROPICAL ATLANTIC S OF 20N E OF 45W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ COBB