000 AXNT20 KNHC 111050 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...ITCZ... ITCZ AXIS IS ANALYZED ALONG 05N04W TO THE EQUATOR NEAR 16W THEN ALONG THE EQUATOR TO 23W AND THEN TO 03S31W AND INTO NE BRAZIL NEAR 03S42W. ISOLATED MODERATE TO STRONG CONVECTION IS FROM 05N-07N BETWEEN 09W-13W...AND FROM THE EQUATOR TO 04N BETWEEN 17W-30W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE COVERS THE GULF OF MEXICO EXTENDING FROM AN ANTICYCLONIC CIRCULATION OVER SOUTHERN MEXICO NEAR 16N98W. THE UPPER LEVEL RIDGE AXIS EXTENDS NE OVER THE SE CONUS AND MUCH OF THE EASTERN UNITED STATES. THIS FEATURE CONTINUES TO SUPPORT A WELL-ESTABLISHED SURFACE RIDGE WITH AXIS EXTENDING FROM THE W ATLC NEAR 30N74W TO THE WEST-CENTRAL GULF NEAR 24N96W. S-SE WINDS IN THE RANGE OF 15 TO 25 KT ARE OCCURRING OVER MUCH OF THE WESTERN TWO-THIRDS OF THE GULF WHICH IS FORECAST TO PERSIST W OF 90W THROUGH MID-DAY MONDAY AS THE NEXT COLD FRONT MOVES ACROSS EASTERN TEXAS THIS MORNING. THE FRONT WILL EMERGE OFF THE TEXAS GULF COAST SHORTLY AFTER NOONTIME MONDAY SHIFTING WINDS N-NE OVER THE NW GULF WATERS BEHIND THE FRONT. 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 OVER 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 THIS MORNING AND IS EXPECTED TO REMAIN IN PLACE THROUGH EARLY THURSDAY AS THE UPPER LEVEL TROUGH AMPLIFIES SLIGHTLY. HIGHER CONVECTIVE WEATHER POTENTIAL TODAY REMAINS EAST OF THE TROUGH AXIS ALONG 70W. E OF 70W...E-NE TRADES CONTINUE WITH A SURFACE TROUGH ANALYZED FROM NE VENEZUELA NEAR 10N64W TO DOMINICA NEAR 16N62W. ISOLATED SHOWERS ARE OCCURRING S OF 18N E OF 68W AND THIS AREA IS FORECAST TO BEGIN MIGRATING 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 SCATTERED 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 32N49W THAT EXTENDS SW TO 29N57W THEN CONTINUES AS A STATIONARY FRONT INTO A 1015 MB LOW CENTERED NEAR 29N61W. THE STATIONARY FRONT THEN EXTENDS SW FROM THE LOW CENTER ALONG 24N68W TO 27N76W BECOMING MORE DIFFUSE W OF 70W. 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 FRONT E OF THE LOW. A WEAK SURFACE TROUGH IS ALSO LOCATED SOUTH OF THE FRONT ANALYZED FROM 18N60W TO 25N58W. ISOLATED SHOWERS ARE NOTED ON INFRARED SATELLITE IMAGERY WITHIN 120 NM EITHER SIDE OF THE SURFACE TROUGH AXIS. 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