000 AXNT20 KNHC 152358 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE MAY 15 2012 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF SIERRA LEONE AT 9N13W AND CONTINUES OVER THE E ATLC WATERS TO 6N21W. THE ITCZ CONTINUES FROM 6N21W ALONG 4N35W 4N51W. CLUSTERS OF MODERATE/STRONG CONVECTION ARE NEAR THE AFRICAN COAST FROM 5N-7N BETWEEN 9W-12W...AND FROM 7N-9N BETWEEN 15W-18W. ...DISCUSSION... THE GULF OF MEXICO... SWLY FLOW ALOFT COVERS THE GULF OF MEXICO THIS EVENING BETWEEN AN UPPER LEVEL RIDGE OVER THE WRN CARIBBEAN AND AN UPPER LEVEL TROUGH MOVING ACROSS TEXAS. THE UPPER TROUGH SUPPORTS A STATIONARY FRONT EXTENDING FROM THE FLORIDA PANHANDLE AT 31N85W ALONG 28N87W 24N94W CONTINUING AS A SURFACE TROUGH TO THE BAY OF CAMPECHE AT 19N93W...AS OF 2100 UTC. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 45 NM EITHER SIDE OF THE FRONT AXIS WITH ACTIVITY ALSO COVERING THE FAR SE GULF INCLUDING THE YUCATAN CHANNEL AND CUBA...AS WELL AS ACROSS MUCH OF THE FLORIDA PENINSULA. THE FLORIDA PENINSULA ACTIVITY IS ALSO INFLUENCED BY SEABREEZE CONVERGENCE WHICH TYPICALLY SETS UP OVER THE MIDDLE OF THE STATE. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS HAVE ALSO FORMED NEAR THE TEXAS COASTLINE WHERE A SURFACE TROUGH PARALLELS THE COASTLINE...AS OF 2100 UTC. THIS ACTIVITY LIES JUST E OF THE UPPER TROUGH AXIS WHERE THE MOST DIFFLUENCE ALOFT EXISTS. THE FRONT IS EXPECTED TO REMAIN MOSTLY STATIONARY FOR THE NEXT 24 HOURS. MOIST CONDITIONS ARE ALSO EXPECTED TO STAY OVER MUCH OF THE ERN GULF. THE CARIBBEAN SEA... SHOWERS/THUNDERSTORMS COVER MUCH OF THE FAR WRN CARIBBEAN INCLUDING CENTRAL AMERICA...YUCATAN PENINSULA...AND WRN CUBA. THIS ACTIVITY IS ASSOCIATED WITH MOIST SWLY FLOW ALOFT BETWEEN AN UPPER LEVEL TROUGH OVER TEXAS AND AN UPPER LEVEL RIDGE EXTENDING FROM THE W ATLC TO NICARAGUA. SOME ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE NRN CARIBBEAN ISLANDS INCLUDING HISPANIOLA AND PUERTO RICO. THE REMAINDER OF THE BASIN IS EXPERIENCING MOSTLY FAIR WEATHER WITH CLEAR SKIES AND 15-20 KT TRADEWIND FLOW. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE E OF THE LESSER ANTILLES AND MAY IMPACT THE ISLANDS OVERNIGHT. EXPECT MOIST CONDITIONS TO REMAIN OVER THE WRN CARIBBEAN ESPECIALLY CENTRAL AMERICA WHICH IS CURRENTLY RECEIVING HEAVY RAINFALL. FLOODING IS POSSIBLE IN AREAS WHERE THE GROUND IS ALREADY SATURATED FROM PREVIOUS RAINFALL. THE ATLANTIC OCEAN... WHILE SURFACE RIDGING IS COVERING MUCH OF THE W AND CENTRAL ATLC AROUND A 1031 MB HIGH NEAR 42N51W...MOISTURE AND ASSOCIATED SHOWERS AND ISOLATED THUNDERSTORMS COVER THE AREA W OF 71W INCLUDING THE WRN BAHAMAS AND FLORIDA. THIS IS ASSOCIATED WITH MOIST SWLY FLOW ALOFT BETWEEN AN UPPER LEVEL TROUGH EXTENDING FROM THE GREAT LAKES REGION TO TEXAS...AND AN UPPER LEVEL RIDGE OVER THE W ATLC ALONG 69W. A WEAK SURFACE TROUGH IS ALONG 32N62W TO 27N61W SUPPORTING A FEW ISOLATED SHOWERS. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE ALSO E OF THE LESSER ANTILLES S OF 20N BETWEEN 53W-61W. A SMALL AREA OF SHOWERS/THUNDERSTORMS IS ALSO N OF THE ERN CARIBBEAN ALONG A LINE FROM 20N63W TO 23N69W. SOME OF THIS ACTIVITY E OF THE CARIBBEAN IS ASSOCIATED WITH MOIST SWLY ALOFT ALONG WITH DIFFLUENCE AROUND THE E SIDE OF AN UPPER LEVEL TROUGH ACROSS THE ERN CARIBBEAN ALONG 63W. AN UPPER LEVEL TROUGH ALSO COVERS THE ERN ATLC EXTENDING FROM AN UPPER LEVEL LOW OVER THE AZORES ISLANDS AT 41N27W TO 26N52W. THIS UPPER LOW SUPPORTS A SURFACE LOW AND ASSOCIATED SURFACE TROUGH WHICH ENTERS THE DISCUSSION AREA ALONG 32N26W TO 28N29W. NO SHOWERS ARE ASSOCIATED WITH THE TROUGH. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL RIDGE COVERS THE AREA CENTERED NEAR 8N37W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON