000 AXNT20 KNHC 110555 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT MON APR 11 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ... ITCZ AXIS IS ANALYZED ALONG 05N08W 03N19W CROSSING THE EQUATOR NEAR 27W THEN INTO NE BRAZIL NEAR 04S38W. ISOLATED MODERATE TO STRONG CONVECTION IS FROM THE EQUATOR TO 04N BETWEEN 20W-26W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE COVERS THE GULF OF MEXICO EXTENDING FROM ANTICYCLONIC CIRCULATION OVER SOUTHERN MEXICO NEAR 16N96W. THE UPPER LEVEL RIDGE AXIS EXTENDS N-NE OVER THE SE CONUS. THIS FEATURE CONTINUES TO SUPPORT A WELL-ESTABLISHED SURFACE RIDGE ANCHORED BY TWO HIGHS...1020 MB AND 1019 MB...CENTERED IN THE VICINITY OF THE FLORIDA PENINSULA...ONE LOCATED IN THE NE GULF WATERS AND THE OTHER NEAR ANDROS ISLAND BAHAMAS. S-SE WINDS TO 20 KT ARE OCCURRING OVER MUCH OF THE WESTERN TWO-THIRDS OF THE GULF WHICH IS FORECAST TO PERSIST AND INCREASE SLIGHTLY W OF 90W THROUGH MID-DAY MONDAY AS THE NEXT COLD FRONT APPROACHES FROM CENTRAL TEXAS THROUGH THE OVERNIGHT HOURS. THE FRONT WILL EMERGE OFF THE TEXAS GULF COAST SHORTLY AFTER NOONTIME MONDAY SHIFTING WINDS N-NE OVER THE NW GULF WATERS. THE FRONT WILL QUICKLY MOVE EAST OF THE GULF BY EARLY WEDNESDAY WITH LIGHT EASTERLY FLOW EXPECTED ON THE SOUTHERN PERIPHERY OF A SURFACE RIDGE OVER THE MISSISSIPPI RIVER VALLEY AND SE CONUS. CARIBBEAN SEA... DRY AIR AND STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY ACROSS MUCH OF THE WESTERN CARIBBEAN IN ASSOCIATION WITH BROAD TROUGHING EXTENDING FROM THE SW NORTH ATLC REGION. THE UPPER LEVEL TROUGH AXIS EXTENDS THROUGH THE WINDWARD PASSAGE TO THE SE COAST OF NICARAGUA NEAR 11N84W. THIS VERY DRY AIR ALOFT IS SUPPORTIVE OF VERY CLEAR SKIES W OF 68W AND IS EXPECTED TO REMAIN IN PLACE THROUGH EARLY THURSDAY AS THE UPPER LEVEL TROUGH AMPLIFIES SLIGHTLY AND MORE CONVECTIVE WEATHER POTENTIAL REMAINS EAST OF THE TROUGH AXIS ALONG 70W. E OF 70W...E-NE TRADES CONTINUE WITH BROAD SURFACE TROUGHING NOTED OVER THE LESSER ANTILLES THIS EVENING. ISOLATED SHOWERS ARE OCCURRING S OF 17N E OF 67W AND THIS AREA IS FORECAST TO BEGIN MOVING WESTWARD BY EARLY WEDNESDAY AS THE FRONTAL BOUNDARY TO THE NORTH OVER THE W ATLC SHIFTS NE OF THE AREA OVER THE NEXT 24 TO 36 HOURS. TOTAL PRECIPITABLE WATER VALUES REMAIN HIGH OVER THE SE CARIBBEAN AND THIS ADDED LOW-LEVEL MOISTURE WILL CONTINUE TO SUPPORT SHOWER ACTIVITY E OF 70W OVER THE NEXT COUPLE OF DAYS. ATLANTIC OCEAN... A BROAD MIDDLE TO UPPER LEVEL TROUGH IS OVER THE SW NORTH ATLC WATERS THAT SUPPORTS A COLD FRONT ENTERING THE DISCUSSION AREA NEAR 32N50W THAT EXTENDS SW TO 27N62W THEN CONTINUES AS A DISSIPATING STATIONARY FRONT ALONG 26N70W TO 29N76W. THE STRONGEST UPPER LEVEL DYNAMICS APPEARS TO REMAIN N OF 28N WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING WITHIN 150 NM EITHER SIDE OF THE COLD FRONT. A WEAK SURFACE TROUGH IS ALSO LOCATED SOUTH OF THE FRONT ANALYZED FROM 20N59W TO 24N58W. ISOLATED SHOWERS ARE NOTED ON INFRARED SATELLITE IMAGERY WITHIN 120 NM EITHER SIDE OF THE SURFACE TROUGH AXIS AND COVERING AN AREA TO THE EAST FROM 21N-26N BETWEEN 51W-55W. THE REMAINDER OF THE ATLC E OF 45W IS UNDER THE INFLUENCE OF A SURFACE RIDGE EXTENDING FROM THE AZORES NEAR 36N25W TO 20N50W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN