000 AXNT20 KNHC 110540 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED MAY 11 2011 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ... ITCZ AXIS IS ANALYZED FROM 10N14W 3N24W 1N35W THEN ALONG THE EQUATOR W OF 43W TO INLAND OVER SOUTH AMERICA NEAR 51W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 45/60 NM OF 3N BETWEEN 27W-32W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 4N TO S OF THE EQUATOR BETWEEN 42W-50W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER RIDGE COVERS MUCH OF THE GULF EXTENDING FROM THE YUCATAN PENINSULA/YUCATAN CHANNEL TO OVER THE N GULF COAST NEAR THE LOUISIANA/TEXAS BORDER. A WEAK SURFACE RIDGE REMAINS OVER THE E GULF ANCHORED BY A 1015 MB HIGH NEAR 29N84W. E TO SE RETURN FLOW AROUND THE HIGH COUPLED WITH LINGERING LOW LEVEL MOISTURE IS BANKING LOW LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS OVER THE W GULF MAINLY WITHIN 75 NM ALONG THE COAST OF FROM VERACRUZ MEXICO TO GALVESTON TEXAS LEAVING THE REMAINDER OF THE GULF WITH MOSTLY CLEAR SKIES AGAIN TONIGHT. A SHORTWAVE UPPER TROUGH IS DIGGING S OVER THE INLAND PORTIONS OF TEXAS GENERATING A BAND OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND OVER E TEXAS MOVING N OVER E OKLAHOMA. HIGH PRESSURE CENTERED OVER THE NE GULF TONIGHT WILL MEANDER ABOUT THE NE GULF THROUGH THU THEN SHIFT SLIGHTLY S AND WEAKEN FRI BUT WILL MAINTAIN MOSTLY MODERATE TO FRESH SE RETURN FLOW ACROSS THE W GULF. THE SURFACE HIGH WILL SHIFT SE SAT AHEAD OF THE NEXT COLD FRONT WHICH WILL ENTER THE NW GULF SAT MORNING AND REACH FROM NEAR APALACHICOLA TO CORPUS CHRISTI SUN MORNING. CARIBBEAN SEA... A BROAD UPPER RIDGE EXTENDS FROM THE TROPICAL ATLC ACROSS THE S CARIBBEAN WITH NEAR ZONAL WESTERLY FLOW ACROSS THE N CARIBBEAN. A SURFACE TROUGH IS OVER THE NE CARIBBEAN EXTENDING FROM THE TROPICAL ATLC ACROSS THE VIRGIN ISLANDS NEAR 18N63W TO 17N67W WITH SCATTERED SHOWERS WITHIN 120 NM N OF THE SURFACE TROUGH TO OVER THE VIRGIN ISLANDS AND PUERTO RICO AND N OF 17N TO OVER HISPANIOLA BETWEEN 67W-73W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE SW CARIBBEAN S OF 14N W OF 75W TO OVER CENTRAL AMERICA. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN UNDER MOSTLY CLEAR SKIES TONIGHT. THE SURFACE TROUGH WILL MEANDER IN THE GENERAL VICINITY THROUGH THU BEFORE DISSIPATING THU NIGHT. A WEAK COLD FRONT OVER SW N ATLC WILL MOVE SSE AND REACH FROM N COAST OF HISPANIOLA ENE TO CENTRAL ATLC THU MORNING THEN GRADUALLY DISSIPATE THROUGH FRI. FRESH EVENING EASTERLIES ARE EXPECTED IN THE GULF OF HONDURAS AND WINDWARD PASSAGE TONIGHT THROUGH THU. ATLANTIC OCEAN... A BROAD UPPER TROUGH COVERS THE W ATLC N OF 20N BETWEEN 50W AND THE FLORIDA PENINSULA SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N54W EXTENDING ALONG 26N59W TO 24N69W WHERE IT DISSIPATES JUST E OF THE BAHAMAS NEAR 24N75W. SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS ARE WITHIN 120 NM E OF FRONT N OF 29N AND ISOLATED SHOWERS ARE WITHIN 90 NM E OF THE FRONT E OF 61W. NEAR ZONAL WESTERLY FLOW ALOFT DOMINATES THE REMAINDER OF THE ATLC WATERS BETWEEN 20N-30N. AN UPPER LOW IS N OF 32N SUPPORTING A DISSIPATING STATIONARY FRONT N OF THE DISCUSSION AREA AND A SURFACE TROUGH THAT EXTENDS FROM 32N28W TO 26N28W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 120 NM E OF THE SURFACE TROUGH. THE REMNANTS OF A SURFACE TROUGH ARE IN THE CENTRAL TROPICAL ATLC EXTENDING FROM 22N37W TO 17N42W WITH ISOLATED SHOWERS POSSIBLE WITHIN 60 NM EITHER SIDE OF THE SURFACE TROUGH. A SURFACE TROUGH IS OVER THE W TROPICAL ATLC INTO THE NE CARIBBEAN EXTENDING FROM 20N58W ACROSS THE VIRGIN ISLANDS NEAR 18N63W. SCATTERED SHOWERS ARE BEING ENHANCED BY THE UPPER RIDGE THAT DOMINATES THE TROPICAL ATLC AND COVER THE AREA FROM 16N-22N BETWEEN 47W-63W. THE W ATLC COLD FRONT WILL SINK SSE TONIGHT AND WED THEN DRIFT SE OVER THE CENTRAL ATLC WED NIGHT BEFORE DISSIPATING THU. A GALE CENTER N OF THE REGION WILL MOVE SE AND PASS JUST NE OF BERMUDA WED AND THU INCREASING NORTHERLY FLOW OVER THE WATERS E OF THE BAHAMAS AND GENERATING LONG PERIOD NORTHERLY SWELL ACROSS THE REGIONAL WATERS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW