000 AXNT20 KNHC 150543 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT MAY 15 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 0430 UTC. ...ITCZ... ITCZ AXIS IS CENTERED FROM SIERRA LEONE NEAR 7N12W ALONG 3N20W 1N30W 2N40W AND INTO NRN BRAZIL NEAR 1S48W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM S OF THE AXIS BETWEEN 11W-16W. SCATTERED MODERATE/STRONG CONVECTION FROM 3N-5N BETWEEN 21W-30W...AND FROM 2N-6N BETWEEN 40-44W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH COVERS THE ERN GULF OF MEXICO WITH AXIS EXTENDING DOWN THE FLORIDA PENINSULA. THE UPPER TROUGH SUPPORTED A COLD FRONT THAT EXTENDS FROM NE FLORIDA NEAR JACKSONVILLE CONTINUING SW ALONG 26N86W 23N92W 23N97W...AS OF 0300 UTC. RADAR IMAGERY INDICATES A LINE OF STRONG SHOWERS/THUNDERSTORMS WITHIN 60 NM AHEAD OF THE FRONT N OF 27N. STRONG DRY AIR AND SUBSIDENCE COVER THE BASIN BEHIND THE UPPER TROUGH SUPPRESSING CONVECTION AND SUPPORTING FAIR WEATHER ACROSS THE REMAINDER OF THE AREA. A FEW ISOLATED SHOWERS ARE NOTED OFF THE ERN COAST OF MEXICO NEAR 24N98W AS STORMS INLAND HAVE MOVED EWD OVER WATER. EXPECT THE FRONT TO DRIFT EWD AND DISSIPATE AS A SECONDARY FRONT MOVES IN BEHIND IT MONDAY AND TUESDAY. THIS SETUP WILL PROVIDE MOIST CONDITIONS ACROSS MUCH OF THE ERN GULF OF MEXICO. CARIBBEAN SEA... BROAD UPPER TROUGHING SITS ACROSS THE ENTIRE CARIBBEAN EXTENDING FROM AN UPPER LEVEL LOW OVER THE UPPER MISSISSIPPI VALLEY. WATER VAPOR IMAGERY INDICATES MOSTLY DRY AIR ACROSS THE NW CARIBBEAN WITH MOISTER CONDITIONS S OF 13N AND E OF 67W. THIS PATTERN IS PROVIDING FAIR CONDITIONS ACROSS THE ENTIRE NW PORTION OF THE BASIN. A SURFACE TROUGH EXTENDS ACROSS THE ERN CARIBBEAN FROM NEAR SRN DOMINICAN REPUBLIC TO THE SW CARIBBEAN ALONG 19N69W 12N73W 9N82W. TOTAL PRECIPITABLE WATER IMAGERY SHOWS ENHANCED MOISTURE VALUES E AND S OF THE TROUGH AXIS WHERE SCATTERED SHOWERS/THUNDERSTORMS COVER THE AREA. SOME OF THIS ACTIVITY IS INFLUENCED BY UPPER LEVEL DIFFLUENCE AROUND THE ERN SIDE OF THE UPPER TROUGH. EXPECT SURFACE TROUGHING TO REMAIN ACROSS THE ERN CARIBBEAN WITH ENHANCED MOISTURE LEVELS SUPPORTING CONVECTION. ATLANTIC OCEAN... UPPER LEVEL DIFFLUENCE AROUND AN UPPER LEVEL TROUGH WITH AXIS DOWN THE FLORIDA PENINSULA IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS N OF 26N BETWEEN 75W-80W. THE REMAINDER OF THE W ATLC IS EXPERIENCING FAIR CONDITIONS UNDER THE INFLUENCE OF DRY AIR ALOFT AND SURFACE RIDGING AROUND A 1014 MB HIGH NEAR 28N73W. HOWEVER...FARTHER E ANOTHER LOW PRESSURE SYSTEM IS IMPACTING THE CENTRAL ATLC. AN UPPER LEVEL TROUGH IS ALONG 54W SUPPORTING A 1006 MB LOW NEAR 35N59W. A SURFACE TROUGH EXTENDS SWD FROM THE LOW CENTER TO NEAR 26N61W DEPICTING THE MAIN WIND SHIFT. THE ACTIVE WEATHER IS FARTHER E ASSOCIATED WITH UPPER LEVEL DIFFLUENCE. SCATTERED SHOWERS/THUNDERSTORMS ARE BETWEEN 45W-51W N OF 23N...AND BETWEEN 50W-67W S OF 23N. THE ERN ATLC IS EXPERIENCING GENERALLY FAIR WEATHER UNDER AN UPPER LEVEL RIDGE ALONG 38W SUPPORTING A SURFACE RIDGE ALONG 35W. AN UPPER LEVEL LOW CONTINUES TO SPIN NE OF THE CANARY ISLANDS NEAR 34N20W SUPPORTING A PAIR OF 1012 MB LOWS NEAR 30N18W AND 32N12W. MINIMAL ACTIVE WEATHER IS ASSOCIATED WITH EITHER LOW IN THE DISCUSSION AREA. EXPECT MOIST CONDITIONS TO REMAIN ACROSS THE CENTRAL ATLC WITH ACTIVITY INCREASING OVER THE W ATLC AS A COLD FRONT OVER THE GULF OF MEXICO PROGRESSES EWD INTO THE W ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON