000 AXNT20 KNHC 151051 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1030 UTC. ...ITCZ... ITCZ AXIS IS CENTERED FROM LIBERIA NEAR 6N11W ALONG 3N20W 3N30W 3N40W AND INTO NRN BRAZIL NEAR 1S50W. AN EMBEDDED SURFACE TROUGH IS ALSO EXTENDS FROM 7N39W TO 1N41W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 150 NM N OF THE AXIS BETWEEN 12W-18W...AND WITHIN 120 NM N OF THE AXIS BETWEEN 21W-26W. SIMILAR ACTIVITY IS W OF THE TROUGH AXIS FROM 1N-5N BETWEEN 42W-46W. ...DISCUSSION... GULF OF MEXICO... MAINLY NWLY FLOW ALOFT COVERS THE GULF OF MEXICO BETWEEN AN UPPER LEVEL RIDGE ACROSS MEXICO AND AN UPPER LEVEL TROUGH WITH AXIS NOW JUST E OF THE FLORIDA PENINSULA. THE UPPER TROUGH CONTINUES TO SUPPORT A COLD FRONT THAT EXTENDS FROM NE FLORIDA NEAR JACKSONVILLE TO TAMPA CONTINUING ALONG 24N86W 21N92W...AS OF 0900 UTC. RADAR IMAGERY INDICATES A LINE OF STRONG SHOWERS/THUNDERSTORMS WITHIN 60 NM AHEAD OF THE FRONT FROM 25N-29N. 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 SMALL AREA OF UPPER LEVEL MOISTURE IS NOTED OVER THE SW GULF SUPPORTING A FEW HIGH CLOUDS. 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 FAR ERN GULF OF MEXICO. CARIBBEAN SEA... BROAD UPPER TROUGHING SITS ACROSS THE ENTIRE CARIBBEAN EXTENDING FROM AN UPPER LEVEL LOW OVER THE OHIO VALLEY. WATER VAPOR IMAGERY INDICATES MOSTLY DRY AIR ACROSS THE NW AND CENTRAL CARIBBEAN WITH MOISTER CONDITIONS E OF 70W. THIS PATTERN IS PROVIDING FAIR CONDITIONS ACROSS THE ENTIRE NW AND CENTRAL PORTIONS OF THE BASIN. A SURFACE TROUGH EXTENDS ACROSS THE ERN CARIBBEAN FROM PUERTO RICO TO COLOMBIA ALONG 18N67W 14N71W 9N75W. TOTAL PRECIPITABLE WATER IMAGERY SHOWS ENHANCED MOISTURE VALUES E OF 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. A FEW ISOLATED SHOWERS ARE ALSO NOTED W OF THE SURFACE TROUGH AXIS FROM 11N-14N BETWEEN 73W-78W. EXPECT SURFACE TROUGHING TO REMAIN ACROSS THE ERN CARIBBEAN WITH ENHANCED MOISTURE LEVELS SUPPORTING CONVECTION. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH NOW SITS JUST E OF THE FLORIDA PENINSULA DOWN 80W SUPPORTING A COLD FRONT ACROSS THE ERN GULF OF MEXICO. UPPER LEVEL DIFFLUENCE AROUND AROUND THE UPPER TROUGH IS SUPPORTING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 26N BETWEEN 74W-78W. ANOTHER LINE OF STORMS IS MOVING ACROSS CENTRAL FLORIDA. THE REMAINDER OF THE W ATLC IS EXPERIENCING FAIR CONDITIONS UNDER THE INFLUENCE OF DRY AIR ALOFT AND SURFACE RIDGING AROUND A WEAK 1013 MB HIGH NEAR 25N61W. HOWEVER...FARTHER E ANOTHER LOW PRESSURE SYSTEM IS IMPACTING THE CENTRAL ATLC. AN UPPER LEVEL TROUGH IS ALONG 53W SUPPORTING A 1007 MB LOW NEAR 34N57W. A SURFACE TROUGH EXTENDS SWD FROM THE LOW CENTER TO NEAR 28N60W DEPICTING THE MAIN WIND SHIFT. THE ACTIVE WEATHER IS FARTHER E ASSOCIATED WITH UPPER LEVEL DIFFLUENCE. SCATTERED SHOWERS/THUNDERSTORMS ARE BETWEEN 44W-51W N OF 23N. A SURFACE TROUGH IS ALSO FARTHER S EXTENDING FROM NEAR 22N60W TO PUERTO RICO AND INTO THE CARIBBEAN. SCATTERED SHOWERS/THUNDERSTORMS ARE S OF 23N BETWEEN 55W-65W. 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 30N19W 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