000 AXNT20 KNHC 231103 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURES... A 1011 MB NON-TROPICAL LOW CONTINUES TO SPIN ABOUT 500 NM S OF BERMUDA NEAR 24N65W MOVING S NEAR 10 KT. THIS IS A DEEP LAYERED LOW WITH THE UPPER LEVEL LOW NEAR 26N62W. WATER VAPOR SATELLITE IMAGERY SHOWS DRY AIR ALOFT NEARLY SURROUNDS THE UPPER LOW EXCEPT TO THE NE. A SURFACE TROUGH EXTENDS FROM THE SURFACE LOW E TO 24N57W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE FROM 22N-25N BETWEEN 61W-65W. 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 ALOFT ALONG WITH UNFAVORABLE UPPER LEVEL WINDS ARE EXPECTED TO HINDER FURTHER DEVELOPMENT. ...ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 7N11W 3N19W CROSSING THE EQUATOR NEAR 35N CONTINUING S OF THE EQUATOR TO INLAND OVER SOUTH AMERICA. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 6N TO S OF THE EQUATOR BETWEEN 5W-14W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 4N TO S OF THE EQUATOR BETWEEN 19W-29W AND FROM 2N TO S OF THE EQUATOR BETWEEN 35W-44W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH REMAINS OVER THE CENTRAL PLAIN STATES MOVING ACROSS THE UPPER MISSISSIPPI VALLEY WITH A SURFACE TROUGH AND DRY LINE INLAND OVER CENTRAL TEXAS AND MEXICO. 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 THIS MORNING WITH SOME PATCHES OF HAZE OVER THE NW GULF N OF 27N W OF 89W. A SURFACE RIDGE CONTINUES TO BUILD FROM THE NE GULF TO THE CENTRAL GULF GIVING THE AREA 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 EXTEND 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 E CARIBBEAN. STRONG HIGH PRESSURE OVER THE FAR W ATLC WILL PRODUCE AN AREA OF FRESH NE WINDS OVER THE N CARIBBEAN INCLUDING THE WINDWARD AND MONA PASSAGES THROUGH SUN BRINGING A PATCHES OF LOW LEVEL CLOUDS AND SCATTERED SHOWERS TO THE AREA FROM 16N-20N BETWEEN 70W-82W. BROAD PRESSURE GRADIENT ACROSS THE REMAINDER OF THE CARIBBEAN IS PRODUCING LIGHT TO MODERATE NE TO E TRADE WINDS ACROSS THE REMAINDER OF 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 LA GUAJIRA PENINSULA OF COLOMBIA LEAVING THE REMAINDER OF THE CARIBBEAN WITH MOSTLY CLEAR SKIES THIS MORNING. ATLANTIC OCEAN... SEE SPECIAL FEATURES ABOVE FOR THE 1011 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 60W-75W SUPPORTING A STATIONARY FRONT THAT ENTERS THE W ATLC NEAR 32N57W TO 29N64W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 28N-30N BETWEEN 59W-62W. AN ELONGATED N/S UPPER LOW IS OVER THE E/CENTRAL ATLC NEAR 31N40W 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 N OF 22N BETWEEN 47W-58W. THE REMAINDER OF THE CENTRAL AND E ATLC ARE DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A 1031 MB HIGH SE OF THE AZORES PROVIDING FAIR WEATHER E OF 47W. BROAD UPPER RIDGE DOMINATES THE TROPICAL ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW