000 AXNT20 KNHC 130547 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST SUN MAR 13 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ... ITCZ AXIS IS ANALYZED ALONG 8N12W 4N16W CROSSING THE EQUATOR NEAR 23W INTO NE BRAZIL SOUTH OF THE EQUATOR. A SURFACE TROUGH EXTENDS FROM 3N49W TO S OF THE EQUATOR TO INLAND OVER BRAZIL NEAR 1S48W WITH SCATTERED STRONG CONVECTION FROM 2N-6N BETWEEN 47W-51W. SCATTERED/NUMEROUS STRONG CONVECTION COVERS THE AREA FROM 4N TO THE EQUATOR BETWEEN 28W-35W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 4N TO S OF THE EQUATOR BETWEEN 10W-13W AND FROM 4N TO S OF THE EQUATOR W OF 36W TO INLAND OVER SOUTH AMERICA. ...DISCUSSION... GULF OF MEXICO... NEAR ZONAL WESTERLY FLOW ALOFT DOMINATES THE GULF WITH STRONG SUBSIDENCE AND DRY STABLE AIR. A SURFACE RIDGE COVERS THE GULF EXTENDING INTO THE W ATLC ANCHORED BY A 1025 MB HIGH OFF THE FLORIDA COAST NEAR 29N84W AND A SECOND 1025 MB HIGH IN THE W ATLC. THIS IS GIVING THE GULF WATERS CLEAR SKIES TONIGHT WITH THE EXCEPTION OF SCATTERED LOW CLOUDS AND POSSIBLE ISOLATED SHOWERS IN THE STRAITS OF FLORIDA S OF THE FLORIDA KEYS E OF 83W. SOUTHERLY RETURN FLOW AROUND THE HIGH HAS BEGUN OVER THE W GULF AND IS EXPECTED TO EXPAND EASTWARD. A WEAK COLD FRONT IS EXPECTED TO APPROACH THE FAR NW GULF ON MON THEN MOVE ACROSS THE NORTH-CENTRAL GULF MON NIGHT AND TUE. CARIBBEAN SEA... A BROAD UPPER RIDGE COVERS THE CARIBBEAN ANCHORED IN THE DEEP TROPICS GIVING THE CARIBBEAN S TO SW FLOW ALOFT. MODERATE SUBSIDENCE AND MOSTLY DRY STABLE AIR DOMINATE THE CARIBBEAN TONIGHT. HOWEVER...LOW LEVEL REMNANT MOISTURE REMAINS ACROSS THE BASIN GENERATING PATCHES OF LOW LEVEL CLOUDS AND SCATTERED SHOWERS MAINLY N OF 12N E OF 72W...N OF 14N BETWEEN 72W-79W... AND S OF 16N W OF 79W TO INLAND OVER CENTRAL AMERICA. HIGH PRESSURE OVER THE W ATLC WILL SHIFT EASTWARD SUN THROUGH WED INCREASING TRADE WINDS OVER THE CENTRAL AND SW CARIBBEAN. ATLANTIC OCEAN... AN UPPER TROUGH CONTINUES TO SLOWLY MOVE ACROSS THE NW ATLC SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N61W EXTENDING TO 27N64W WHERE IT BECOMES A SHEAR AXIS TO ACROSS THE TURKS AND CAICOS TO 21N74W. ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE FRONT. A SURFACE RIDGE IS BUILDING W OF THE FRONT ACROSS FLORIDA INTO THE GULF OF MEXICO ANCHORED BY A 1025 MB HIGH OFF THE FLORIDA COAST NEAR 28N79W AND A SECOND 1025 MB HIGH IN THE GULF OF MEXICO. FARTHER EAST INTO THE CENTRAL ATLC IS A WEAKENING CUT OFF UPPER LOW CENTERED NEAR 23N42W SUPPORTING A WEAK SURFACE TROUGH ANALYZED FROM 25N52W TO NEAR 20N37W. LOW LEVEL SPEED CONVERGENCE ALONG WITH THE UPPER LEVEL DIFFLUENT ENVIRONMENT PROVIDED BY THE UPPER LEVEL LOW IS GENERATING SCATTERED SHOWERS COVERING THE AREA E OF THE SURFACE TROUGH FROM 20N-26N BETWEEN 30W-42W. ELSEWHERE OVER THE E ATLC A DISSIPATING COLD FRONT EXTENDS TROUGH 32N18W TO 28N31W WITH POSSIBLE ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF THE FRONT. THIS FRONT IS SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH LOCATED N OF 27N E OF 30W TO THE NW COAST OF AFRICA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW