000 AXNT20 KNHC 230600 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT APR 23 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURE... A 1010 MB NON-TROPICAL LOW CONTINUES TO SPIN ABOUT 415 NM S OF BERMUDA NEAR 25N65W. THIS IS A DEEP LAYERED LOW WITH THE UPPER LEVEL LOW NEAR 24N65W. WATER VAPOR SATELLITE IMAGERY SHOWS DRY AIR ALOFT INTRODUCED INTO THE UPPER LOW TO THE E AND SURROUNDING THE UPPER LOW MAINLY TO THE WEST AND SOUTH. SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS ARE TO THE SE OF THE SURFACE LOW FROM 24N-26N BETWEEN 61W-65W. A SURFACE TROUGH EXTENDS FROM THE SURFACE LOW ALONG 23N63W 26N60W 22N61W TO THE VIRGIN ISLANDS NEAR 18N65W WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 90/120 NM E OF THE TROUGH N OF 23N E OF 63W. UPPER LEVEL WINDS ARE INCREASINGLY LESS CONDUCIVE FOR DEVELOPMENT AND ARE FORECAST TO BECOME HIGHLY UNFAVORABLE FOR DEVELOPMENT DURING THE NEXT 48 HOURS. THE DRY AIR INTRUSION ALONG WITH UNFAVORABLE UPPER LEVEL WINDS ARE EXPECTED TO HINDER FURTHER DEVELOPMENT. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 5N8W 4N16W CROSSING THE EQUATOR NEAR 22N CONTINUING S OF THE EQUATOR TO INLAND OVER SOUTH AMERICA. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 5N TO S OF THE EQUATOR BETWEEN 3W-20W...FROM 3N TO S OF THE EQUATOR BETWEEN 20W-29W...AND FROM 2N TO S OF THE EQUATOR BETWEEN 35W-45W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH IS OVER THE CENTRAL PLAIN STATES MOVING TOWARD THE MISSISSIPPI VALLEY WITH A SURFACE TROUGH AND DRY LINE INLAND OVER CENTRAL TEXAS AND MEXICO GENERATING SCATTERED SHOWERS/ THUNDERSTORMS. HOWEVER A DRY AND STABLE AIRMASS REMAINS ACROSS THE GULF WITH AN UPPER HIGH OVER THE FLORIDA PENINSULA. THIS DRY AIRMASS IS LIMITING SHOWER ACTIVITY OVER THE GULF WATERS TONIGHT WITH SOME PATCHES OF FOG/HAZE OVER THE NW GULF N OF 26N W OF 89W. A SURFACE RIDGE IS BUILDING FROM THE NE GULF GIVING THE GULF E TO SE SURFACE FLOW WHICH WILL CONTINUE THROUGH TUE AHEAD OF THE NEXT COLD FRONT THAT WILL MOVE OFF THE TEXAS COAST WED MORNING. THIS COLD FRONT WILL RACE E AND DISSECT THE GULF FROM THE FLORIDA BIG BEND TO THE BAY OF CAMPECHE LATE WED NIGHT. CARIBBEAN SEA... BROAD UPPER RIDGE DOMINATES THE CARIBBEAN ANCHORED IN THE W TROPICAL ATLC DRAWING UPPER LEVEL MOISTURE ACROSS THE SE CARIBBEAN. BROAD PRESSURE GRADIENT IS PRODUCING LIGHT TO MODERATE NE TO E TRADE WINDS ACROSS THE AREA. THESE TRADE WINDS ARE BRINGING PATCHES OF LOW LEVEL CLOUDS OVER THE SE CARIBBEAN AND COUPLED WITH THE UPPER LEVEL MOISTURE ARE GENERATING SCATTERED SHOWERS OVER THE SE CARIBBEAN S OF A LINE FROM GUADELOUPE IN THE LEEWARD ISLANDS TO THE ABC ISLANDS OFF THE COAST OF VENEZUELA. AFTERNOON SHOWERS THAT DEVELOPED OVER HISPANIOLA HAVE MOVED INTO THE CARIBBEAN WATERS ON THE NE TO E TRADE WINDS LEAVING THE REMAINDER OF THE CARIBBEAN WITH MOSTLY CLEAR SKIES TONIGHT. ATLANTIC OCEAN... SEE SPECIAL FEATURES ABOVE FOR THE 1010 MB LOW/TROUGH IN THE W/CENTRAL ATLC. AN UPPER TROUGH IS OVER THE NW ATLC DIPPING INTO THE DISCUSSION AREA N OF 28N BETWEEN 65W-75W SUPPORTING A COLD FRONT THAT ENTERS THE W ATLC NEAR BERMUDA EXTENDING SW TO 29N72W WHERE IT CONTINUES AS A DISSIPATING STATIONARY FRONT ALONG 28N75W THEN NW TO INLAND OVER GEORGIA JUST S OF SAVANNAH. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 30N BETWEEN 77W-79W. AN ELONGATED N/S UPPER LOW IS OVER THE E/CENTRAL ATLC NEAR 31N42W WITH AN UPPER RIDGE BETWEEN THIS UPPER LOW AND THE UPPER LOW ASSOCIATED WITH THE SPECIAL FEATURES. THIS UPPER RIDGE IS PROVIDING DIFFLUENCE ALOFT TO GENERATE AN AREA OF SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 23N-30N BETWEEN 49W-55W. THE REMAINDER OF THE CENTRAL AND E ATLC ARE DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A 1030 MB HIGH NEAR 33N35W PROVIDING FAIR WEATHER E OF 48W. BROAD UPPER RIDGE DOMINATES THE TROPICAL ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW