000 AXNT20 KNHC 220000 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT MAY 21 2011 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 2345 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS INLAND OVER SOUTH AMERICA ALONG 72W TO THE SOUTH OF 10N MOVING W AT 5-10 KT. THE WAVE EXTENDS ACROSS W VENEZUELA AND E COLOMBIA TO NEAR 2N. EXCEPT FOR CYCLONIC TURNING IN THE VICINITY OF THE WAVE AXIS NOTED ON VISIBLE SATELLITE IMAGERY...WAVE HAS BECOME DIFFICULT TO DEPICT. SCATTERED MODERATE-STRONG CONVECTION IS WITHIN 150/200 NM ON EITHER SIDE OF THE AXIS. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED FROM THE COAST OF LIBERIA NEAR 6N10W WESTWARD ALONG 2N20W 2N30W 4N40W 6N50W INTO FRENCH GUIANA NEAR 5N53W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM OF THE COASTAL WATERS OF W AFRICA FROM 4N-12N. SIMILAR CONVECTION IS FROM THE EQUATOR TO 8N BETWEEN 17W-27W. SCATTERED WEAK TO MODERATE CONVECTION IS ELSEWHERE WITHIN 100 NM ON EITHER SIDE OF THE ITCZ...INCLUDING THE COASTS OF FRENCH GUIANA... SURINAME...AND GUYANA. ...DISCUSSION... GULF OF MEXICO... A MID-UPPER LEVEL RIDGE COVERS THE GULF THIS EVENING...PROVIDING DRY SUBSIDENT AIR ALOFT ACROSS THE AREA. THE RIDGE SUPPORTS A 1017 MB HIGH CENTERED OVER THE NE GULF NEAR 29N85W. WHILE LIGHT AND VARIABLE WINDS ARE OBSERVED NEAR THE HIGH CENTER...SE WINDS 10-15 KT ARE ELSEWHERE S OF 27N W OF 87W. HAZY SKIES ARE NOTED ACROSS THE WESTERN HALF OF THE GULF W OF 90W ON VISIBLE SATELLITE IMAGERY...DUE TO SEVERAL WILD FIRES IN SOUTHERN MEXICO AND THE YUCATAN PENINSULA. SURFACE OBSERVATIONS ACROSS THE TEXAS COAST ARE REPORTING LOW CEILINGS WITH VISIBILITIES DOWN TO 2.5 SM DUE TO THE CONCENTRATION OF HAZE IN THIS REGION. WEATHER CONDITIONS ACROSS THE GULF ARE EXPECTED TO REMAIN CONSTANT OVER THE NEXT 24 HOURS. CARIBBEAN SEA... WATER VAPOR IMAGERY INDICATES A SLOW MOVING UPPER LEVEL TROUGH OVER THE NW PORTION OF THE CARIBBEAN SEA. DRY SUBSIDENT AIR ALOFT ACCOMPANIES THE UPPER TROUGHING W OF 75W. THE UPPER LEVEL TROUGH IS INDUCING BROAD CYCLONIC TURNING COVERING THE CENTRAL BASIN. THIS SCENARIO IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS BETWEEN 67W-73. A SURFACE TROUGH IS ANALYZED WITHIN THIS REGION OF CONVECTION...FROM 17N72W TO 11N71W. THE CONVECTION IS FURTHER SUPPORTED BY UPPER LEVEL DIFFLUENCE EXTENDING FROM THE SW ATLC INTO THE NE AND N CENTRAL CARIBBEAN. THE SURFACE TROUGH HAS DISRUPTED NORMAL EASTERLY TRADES ACROSS THE CENTRAL PORTION OF THE BASIN...AND GLOBAL MODEL GUIDANCE SUGGEST THIS SYNOPTIC SETUP WILL REMAIN IN PLACE FOR THE NEXT 24-48 HOURS. ATLANTIC OCEAN... WATER VAPOR IMAGERY SHOWS A DEEP LAYERED LOW/TROUGH OVER THE WESTERN N ATLC WITH MID-UPPER LEVEL TROUGHING EXTENDING SW ACROSS THE W ATLC INTO THE NW CARIBBEAN SEA. THIS SYSTEM SUPPORTS A COLD FRONT THAT ENTERS THE REGION ALONG 32N66W TO 30N70W GENERATING A FEW SHOWERS WITHIN 20 NM EAST OF IT. A BROAD AREA OF SCATTERED SHOWERS AND THUNDERSTORMS IS FOUND FARTHER EAST N OF 18N BETWEEN 52W-65W...ASSOCIATED TO BROAD UPPER LEVEL DIFFLUENCE EXTENDING FROM THE SW ATLC INTO THE NE AND N CENTRAL CARIBBEAN. WITHIN THIS AREA OF CONVECTION...A SURFACE TROUGH IS ANALYZED FROM 26N59W TO 21N63W. A SECONDARY TROUGH IS ANALYZED FROM 29N53W TO 26N55W. SURFACE RIDGING COVERS THE REMAINDER OF THE EASTERN ATLC E OF 50W...PROVIDING FAIR WEATHER CONDITIONS ACROSS THE AREA. GLOBAL MODEL GUIDANCE SUGGEST THE SYNOPTIC SETUP ACROSS THE ATLC WILL REMAIN IN PLACE FOR THE NEXT 24-48 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA