000 AXNT20 KNHC 302335 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED MAR 30 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2330 UTC. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED FROM THE COAST OF LIBERIA NEAR 5N10W SW ALONG 2N20W EQ30W 1S40W INTO NE BRAZIL NEAR 2S47W. ISOLATED WEAK TO MODERATE CONVECTION IS WITHIN 180 NM ON EITHER SIDE OF THE AXIS BETWEEN W OF 16W. ...DISCUSSION... THE GULF OF MEXICO... A MID-UPPER LEVEL TROUGH MOVES ACROSS THE EASTERN HALF OF THE CONUS SUPPORTING A LOW PRESSURE SYSTEM LOCATED OVER SW GEORGIA. A COLD FRONT EXTENDS SW FROM THE LOW CENTER ENTERING THE GULF BASIN THROUGH JUST EAST OF PORT ST JOE FLORIDA AND CONTINUING ACROSS THE GULF ALONG 26N90W BECOMING STATIONARY NEAR 25N92W TO VERACRUZ MEXICO. DESPITE THE EXTENSION OF THE FRONTAL SYSTEM ...MOST OF THE INSTABILITY AND LOW-LEVEL CONVERGENCE IS FOCUSED WITHIN 150 NM EAST OF THE FRONT N OF 27N...AFFECTING THE COASTAL WATERS FROM SARASOTA TO CEDAR KEY. COMPOSITE DOPPLER RADAR IMAGERY INDICATES SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS IN THIS REGION. THIS FRONT WILL CONTINUE TO TRACK EAST OVER THE NEXT 24 HOURS WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MOVING SE ACROSS THE FLORIDA STRAITS OVER THE NEXT 24 HOURS. THE CARIBBEAN SEA... DRY AIR AND STRONG SUBSIDENCE ALOFT IS NOTED ACROSS THE CARIBBEAN SEA THIS EVENING. AT SURFACE...FRESH TO STRONG TRADE WINDS PERSIST WITH VERY FEW AREAS OF SHOWER ACTIVITY. THE FLOW TURNS SE W OF 75W N OF 16N IN RESPONSE OF THE WEATHER SYSTEM MENTIONED IN THE GULF OF MEXICO DISCUSSION. THE ONLY FEATURE OF IMPORTANCE IS A WEAK SURFACE TROUGH MOVING ACROSS PUERTO RICO ALONG 66W N OF 15N PROVIDING A FEW ISOLATED SHOWERS WITHIN 130 NM ON EITHER SIDE OF THE AXIS. THIS SYSTEM WILL CONTINUE TO MOVE WNW OVER THE NEXT 24 HOURS. ALSO...SCATTERED SHOWERS ARE EXPECTED TO DEVELOP OVER THE SW BASIN S OF 14N W OF 75W DURING THE FORECAST PERIOD. THE ATLANTIC OCEAN... A MID-UPPER LEVEL TROUGH IS OVER THE EASTERN HALF OF THE CONUS SUPPORTING A LOW PRESSURE SYSTEM MOVING OFF THE CAROLINAS AND ANOTHER LOW PRESSURE SYSTEM LOCATED OVER SW GEORGIA. AS THE TWO SYSTEMS MOVE OFF THE SEABOARD...SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS ALREADY ENTERING THE FAR WESTERN ATLC W OF 74W N OF 27N. DOPPLER RADAR IMAGERY AND LIGHTNING DATA INDICATED A LINE OF NUMEROUS SHOWERS AND SCATTERED TSTMS OCCURRING WITHIN THIS AREA OF CONVECTION. THIS SYSTEM WILL CONTINUE TO AFFECT THE WESTERN ATLC OVER THE NEXT 24 HOURS. A NORTH ATLC DEEP LAYER TROUGH EXTENDS A FRONTAL SYSTEM THAT ENTERS OUR REGION AS A COLD FRONT NEAR 32N48W CONTINUING SW ALONG 27N60W TO 28N70W. A PRE FRONTAL TROUGH IS ANALYZED 50-100 NM AHEAD OF THE FRONT. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 70 NM ON EITHER SIDE OF BOTH THE COLD FRONT AND PRE FRONTAL TROUGH. THIS FRONTAL BOUNDARY IS EXPECTED TO CONTINUE TO TRACK EASTWARD WITH CONVECTION OVER THE NEXT 24 HOURS. A WEAK SURFACE TROUGH MOVES ACROSS PUERTO RICO ALONG 66W S OF 22N PROVIDING A FEW ISOLATED SHOWERS WITHIN 130 NM ON EITHER SIDE OF THE AXIS. THIS TROUGH MOVES AROUND THE EXTREME SW PORTION OF A BROAD SURFACE RIDGE THAT EXTENDS ITS AXIS ACROSS THE EAST AND CENTRAL ATLC. HENCE... THE REMAINDER OF THE ATLC BASIN IS UNDER THE INFLUENCE OF THIS BROAD SURFACE RIDGE ANCHORED BY A 1027 MB HIGH CENTERED EAST OF PORTUGAL NEAR 38N12W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA