000 AXNT20 KNHC 260529 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN MAY 26 2013 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 11N15W TO 6N24W. THE ITCZ BEGINS FROM 6N24W AND CONTINUES ALONG 4N36W 4N47W 3N51W. A LARGE BURST OF STRONG CONVECTION IS FROM 4N-9N BETWEEN 16W-24W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-9N BETWEEN 48W-53W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL RIDGING SPREADS OVER THE GULF OF MEXICO TONIGHT WITH AXIS NEAR 91W SUPPORTING SURFACE RIDGING EXTENDING FROM A HIGH CENTER OVER THE WEST ATLC. DRY AIR ALOFT COVERS A GOOD PORTION OF THE EASTERN HALF OF THE BASIN PROVIDING FAIR CONDITIONS AND CLEAR SKIES. DIFFLUENT FLOW ALOFT AROUND THE WEST SIDE OF THE UPPER RIDGE IS PROVIDING CLOUD COVER AND POSSIBLE ISOLATED SHOWERS OVER THE FAR WESTERN GULF. ISOLATED SHOWERS ARE ALSO IN THE BAY OF CAMPECHE NEAR A SURFACE TROUGH ALONG 22N89W TO 18N90W. A CLUSTER OF STRONG SHOWERS/THUNDERSTORMS IS ALSO INLAND OVER SOUTHERN MEXICO FROM 16N-20N BETWEEN 92W-95W. MAINLY EAST TO SOUTHEAST WINDS ARE THROUGHOUT THE AREA RANGING FROM 10-15 KT. A FEW 20 KT WINDS MAY BE PRESENT NEAR THE WESTERN COAST OF THE YUCATAN PENINSULA. SURFACE RIDGING WILL DOMINATE THE AREA THROUGHOUT THE WEEKEND. CARIBBEAN SEA... CLEAR SKIES SPREAD ACROSS A LARGE AREA OF THE CARIBBEAN INCLUDING THE NW AND SE CORNERS. HOWEVER...A COUPLE AREAS OF SHOWERS/THUNDERSTORMS ARE STILL PRESENT. THE FIRST AREA IS IN THE SW CARIBBEAN WHERE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 12N-17N BETWEEN 80W-88W INCLUDING NICARAGUA AND HONDURAS. IT COINCIDES WITH AN AREA OF MAXIMUM MOISTURE IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO OVER SOUTHERN HAITI FROM 18N-19N BETWEEN 71W-74W. THIS IS LIKELY ASSOCIATED WITH AN UPPER LEVEL TROUGH WHOSE AXIS IS ALONG 70W. MOIST SOUTHWESTERLY FLOW ALOFT COVERS THE EASTERN CARIBBEAN EAST OF 70W...BUT ONLY A FEW ISOLATED SHOWERS ARE NOTED WITHIN THE TRADEWIND FLOW OF 15 KT. LITTLE CHANGE IS EXPECTED ACROSS THE BASIN. MOISTURE IS EXPECTED TO REMAIN OVER THE SW CARIBBEAN AS WELL AS THE FAR EASTERN PORTION LIKELY ASSOCIATED WITH THE UPPER TROUGH CURRENTLY ALONG 70W. HISPANIOLA... SCATTERED SHOWERS/ISOLATED THUNDERSTORMS CONTINUE OVER SOUTHERN HAITI FROM 18N-19N BETWEEN 71W-74W. THIS IS THE LAST ACTIVITY THAT REMAINS FROM AFTERNOON CONVECTION. AN UPPER LEVEL TROUGH LIES OVER THE ISLAND ALONG 70W...WHICH MAY BE CONTRIBUTING TO THE LATE ACTIVITY. THE UPPER TROUGH SHOULD MOVE EAST OVER THE NEXT 24 HOURS...WHICH WILL BRING IN DRIER AIR ALOFT. HOWEVER...MODEL GUIDANCE INDICATES LOW-LEVEL MOISTURE EAST OF THE LESSER ANTILLES WILL BEGIN MOVING WEST AND MAY REACH HISPANIOLA WITHIN 48 HOURS. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE IN THE GULF OF MEXICO SUPPORTS SURFACE RIDGING IN THE FAR WESTERN ATLC AROUND A 1024 MB HIGH NEAR 32N79W. AN UPPER LEVEL TROUGH TO THE EAST ALONG 70W SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N66W AND CONTINUES ALONG 27N70W 24N77W. ISOLATED SHOWERS AND THUNDERSTORMS ARE UP TO 300 NM EAST OF THE AXIS NORTH OF 25N. AN UPPER LEVEL RIDGE DOMINATES THE CENTRAL ATLC ALONG 49W SUPPORTING BROAD SURFACE RIDGING ACROSS THIS AREA AROUND A 1037 MB HIGH NEAR 41N41W. AN UPPER LEVEL TROUGH EXTENDS INTO THE EASTERN ATLC FROM NEAR 35N22W TO 28N43W. IT SUPPORTS A WEAK SURFACE TROUGH ALONG 30N40W TO 27N40W. NO SHOWER ACTIVITY IS ASSOCIATED WITH THE TROUGH. THE REMAINDER OF THE BASIN IS ALSO INFLUENCED BY SURFACE RIDGING SUPPORTED BY BROAD UPPER RIDGING ACROSS WEST AFRICA. BROAD UPPER RIDGING ALSO COVERS THE TROPICAL ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON