000 AXNT20 KNHC 231118 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI APR 23 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC... ...THE ITCZ... ITCZ AXIS IS CENTERED FROM NRN LIBERIA NEAR 7N11W ALONG 5N20W 3N30W 1N40W AND INTO NE BRAZIL TO 1N52W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 2N-6N BETWEEN 12W-19W. SIMILAR ACTIVITY IS FROM 2N-4N BETWEEN 30W-36W...FROM 2N-5N BETWEEN 38W-45W...AND FROM 3N-5N BETWEEN 48W-51W. ...DISCUSSION... THE GULF OF MEXICO... SURFACE RIDGING COVERS THE ERN GULF OF MEXICO TONIGHT EXTENDING FROM A 1015 MB HIGH E OF NRN FLORIDA MAINTAINING GENERALLY FAIR WEATHER ACROSS MUCH OF THE BASIN. HOWEVER...POSSIBLE ISOLATED SHOWERS ARE IN THE FAR NW CARIBBEAN N OF 26N W OF 91W. THE SURFACE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE WITH AXIS EXTENDING FROM THE OHIO VALLEY TO THE CENTRAL GULF. UPPER LEVEL MOISTURE BEING DRAWN FROM THE E PACIFIC AROUND THIS UPPER RIDGE COVERS THE GULF SUPPORTING HIGH CLOUDS MOSTLY ACROSS THE WRN HALF OF THE AREA. SURFACE OBSERVATIONS INDICATE MAINLY SE FLOW OF 15-20 KT COVERING MOST OF THE BASIN WITH STRONGER WINDS IN THE NW GULF. AN UPPER LEVEL TROUGH OVER THE WRN CONUS IS FORECAST TO MOVE EWD SUPPORTING A COLD FRONT FORECAST TO MOVE OFF THE TEXAS COAST LATE FRI. THE CARIBBEAN SEA... MUCH OF THE CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER UNDER THE INFLUENCE OF MODERATELY DRY AIR ALOFT IN UPPER LEVEL ZONAL WLY FLOW. A CLUSTER OF SHOWERS/THUNDERSTORMS ARE NOTED OFF THE COAST OF COSTA RICA FROM 11N-12N BETWEEN 80W-83W. ISOLATED SHOWERS ARE ALSO ACROSS THE NE CARIBBEAN ISLANDS INCLUDING PUERTO RICO AND HISPANIOLA. THIS ACTIVITY IS MOST LIKELY ASSOCIATED WITH SURFACE CONVERGENCE NEAR A FRONTAL TROUGH REACHING THE VIRGIN ISLANDS EXTENDING FROM A COLD FRONT IN THE CENTRAL ATLC. ISOLATED SHOWERS ARE N OF 17N BETWEEN 64W-71W. TOTAL PRECIPITABLE WATER IMAGERY ALSO INDICATES ENHANCED LOW-LEVEL MOISTURE OVER THE ERN CARIBBEAN. MODERATE TO FRESH TRADEWINDS ARE ACROSS MUCH OF THE BASIN...AND ARE FORECAST TO INCREASE AS HIGH PRESSURE BUILDS ACROSS THE W ATLC RESULTING IN A STRONGER PRESSURE GRADIENT ACROSS THE CARIBBEAN. THE ATLANTIC OCEAN... THE SURFACE RIDGE OVER THE ERN GULF HAS BEGUN TO SHIFT EWD...AND IS NOW ANCHORED BY A 1015 MB HIGH NEAR 29N78W KEEPING CONDITIONS FAR ACROSS THE FAR W ATLC. A BROAD UPPER LEVEL TROUGH COVERS THE REMAINDER OF THE W ATLC SUPPORTING A LOW PRESSURE SYSTEM N OF THE AREA OFF THE NEW ENGLAND COAST. AN ASSOCIATED COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N62W TO 27N69W. SCATTERED SHOWERS ARE E OF THE FRONT FROM 26N-31N BETWEEN 60W-66W. A SURFACE TROUGH IS E OF THE FRONT FROM 26N57W TO 31N60W MEETING A WARM FRONT THAT EXTENDS OUT OF THE AREA. SCATTERED SHOWERS ARE E OF THE TROUGH/FRONT N OF 29N BETWEEN 53W-57W. A SURFACE RIDGE COVERS THE REMAINDER OF THE CENTRAL AND E ATLC ANCHORED BY A 1016 MB HIGH NEAR 30N43W...AND A 1017 MB HIGH NEAR 25N28W. HOWEVER...A COLD FRONT BISECT THE SURFACE RIDGE BETWEEN THE HIGH CENTERS ENTERING THE DISCUSSION AREA NEAR 32N29W ALONG 27N36W 23N49W CONTINUING AS A SURFACE TROUGH TO THE VIRGIN ISLANDS ALONG 22N57W 19N64W. SCATTERED SHOWERS ARE N OF 25N BETWEEN 27W-53W. ISOLATED SHOWERS ARE FROM 20N-23N BETWEEN 48W-54W...AND ALSO WITHIN 45NM EITHER SIDE OF THE TROUGH AXIS. THE SURFACE RIDGE IS MAINTAINING GENERALLY FAIR WEATHER SE OF THE FRONTAL BOUNDARY. AN UPPER LEVEL RIDGE CENTERED NEAR 12N42W DOMINATES THE E ATLC SUPPORTING THE SURFACE RIDGE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON