000 AXNT20 KNHC 211135 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT MON MAR 21 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... SOUTHWEST AND NORTHWEST MONSOON FLOW CONVERGENCE IS OBSERVED FROM THE SOUTHERN COAST OF LIBERIA NEAR 4N8W TO ABOUT 2N21W. THE ITCZ AXIS IS ANALYZED FROM THAT POINT WESTWARD ALONG 1N30W EQ40W INTO BRAZIL NEAR 2S46W DEPICTING CONVENTIONAL CONVERGENT WIND FLOW. WIDELY SCATTERED MODERATE CONVECTION IS FOUND WITHIN 180 NM ON EITHER SIDE OF THE AXIS E OF 40W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE COVERS THE GULF OF MEXICO THIS EVENING... EXTENDING ITS AXIS DOWN ACROSS THE ERN UNITED STATES INTO NE FLORIDA AND ACROSS THE GULF TO THE BAY OF CAMPECHE. THIS FEATURE ALONG WITH VERY DRY AIR AND STRONG SUBSIDENCE ALOFT IS PROVIDING FAIR WEATHER CONDITIONS ACROSS THE AREA. WINDS ARE LIGHT AND VARIABLE OVER THE FAR NE BASIN...WITH MODERATE TO FRESH EASTERLY WINDS W OF 86W S OF 28N AND SOUTHEASTERLY RETURN FLOW N OF 25N W OF 90W. THE SURFACE RIDGE IS EXPECTED TO REMAIN STATIONARY MAINTAINING FAIR CONDITIONS ACROSS THE BASIN FOR THE NEXT SEVERAL DAYS. CARIBBEAN SEA... THE CARIBBEAN IS UNDER THE INFLUENCE OF A BROAD UPPER LEVEL RIDGE WITH ASSOCIATED DRY AIR AND STRONG SUBSIDENCE ACROSS THE MAJORITY OF THE BASIN...ESPECIALLY OVER THE NW BASIN. THIS SCENARIO IS LIMITING DEEP CONVECTION ACROSS THE AREA...LEAVING JUST A FEW AREAS OF WEAK SHOWERS SCATTERED ACROSS THE REGION. THESE AREAS OF SHOWERS ARE MOVING WITH THE NE FRESH TO STRONG TRADE WIND FLOW. THIS FLOW ALSO GAIN A CYCLONIC TENDENCY AROUND THE COAST OF COLOMBIA WITH WINDS REACHING UP TO 25 KT...CAUSING OROGRAPHIC SHOWER ACTIVITY ALONG THE EAST COASTS EASTERN PANAMA AND COLOMBIA S OF 11N BETWEEN 74W-78W. COMPUTER MODELS SUGGEST SOME WEAK CONVECTION DEVELOPING OVER THE FAR SE BASIN IN WITHIN THE NEXT 24 HOURS...WITH NO OTHER SIGNIFICANT CHANGES EXPECTED DURING THE FORECAST PERIOD. ATLANTIC OCEAN... A COLD FRONT IS PUSHING FURTHER SOUTHWARD INTO THE WEST ATLC ANALYZED ALONG 32N48W 26N55W 24N63W 24N76W. THE FRONT IS SUPPORTED ALOFT BY AN UPPER TROUGH MOVING ACROSS THE NW ATLC N OF THE AREA. SCATTERED SHOWERS ARE FOUND ALONG THE FRONTAL BOUNDARY WITH ISOLATED SHOWERS UP TO 50 NM BEHIND THE FRONT. AN EARLIER ASCAT SCATTEROMETER PASS INDICATED NORTHERLY GUSTY WINDS UP TO 25 KTS BEHIND THE FRONT. THE REMAINDER OF THE W ATLC IS EXPERIENCING FAIR WEATHER DUE TO AN UPPER LEVEL RIDGE COVERING THE FAR WEST ATLC. AHEAD OF THE COLD FRONT...A VERY WEAK CUT-OFF UPPER LOW SPINS NEAR 26N44W. THIS FEATURE SUPPORTS A 1007 MB SURFACE REFLECTION LOW NEAR 28N48W. A SURFACE TROUGH EXTENDS S AROUND THE EASTERN SEMI-CIRCLE OF THE LOW CENTER ALONG 23N44W TO 17N47W. THE COMBINATION OF THESE FEATURES ALONG WITH THE UPPER LEVEL SUPPORT IS GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM 17N TO N OF THE DISCUSSION AREA BETWEEN 37W-47W. THIS SYSTEM IS EXPECTED TO CONTINUE TO TRACK NE OUT OF THE AREA OVER THE NEXT 24 HOURS. THE REMAINDER OF THE CENTRAL AND E ATLC IS DOMINATED BY A 1018 MB HIGH NEAR 30N35W SUPPORTING FAIR WEATHER ACROSS THE AREA E OF 37W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FG/PW