000 AXNT20 KNHC 301033 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT APR 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...ITCZ... ITCZ AXIS IS FROM 05N08W TO THE EQUATOR NEAR 15W...THEN SOUTH OF THE EQUATOR ALONG 03S23W 06S30W AND INTO NE BRAZIL NEAR 03S39W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 01N-06N BETWEEN 01W-07W...AND FROM THE EQUATOR TO 03N BETWEEN 11W-20W. ISOLATED MODERATE CONVECTION IS FROM THE EQUATOR TO 04N BETWEEN 26W-30W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL SHORTWAVE TROUGH IS OVER THE FLORIDA PENINSULA AND IS PART OF A BROADER SCALE UPPER LEVEL TROUGH WITH AXIS EXTENDING ALONG THE EASTERN U.S. SEABOARD FROM THE NEW ENGLAND STATES TO NEAR 30N78W THEN TO A BASE NEAR 26N81W. THIS UPPER LEVEL FEATURE SUPPORTS A COLD FRONT THAT EXTENDS ACROSS THE W ATLC AND SOUTHERN TIP OF THE FLORIDA PENINSULA AND CONTINUES AS A DISSIPATING STATIONARY FRONT INTO THE SE GULF FROM 26N81W TO 25N89W. MOST CONVECTION ASSOCIATED WITH THE FRONT ACROSS THE W ATLC HAS DISSIPATED OVER THE PAST 6 HOURS AS MOSTLY DRY AND SUBSIDENT W-NW FLOW DOMINATES ACROSS THE GULF AS NOTED ON RECENT WATER VAPOR IMAGERY. A WEAK SURFACE RIDGE IS OVER THE NE GULF ANCHORED BY A 1018 MB HIGH CENTERED OVER SOUTHERN GEORGIA NEAR 31N83W. RETURN S-SE FLOW IN THE RANGE OF 10 TO 20 KT...HIGHEST OVER THE NW GULF...IS LOCATED ON THE WESTERN PERIPHERY OF THE RIDGE AND IS EXPECTED TO PERSIST THROUGH EARLY TUESDAY. THEREAFTER...A COLD FRONT IS FORECAST TO EMERGE OFF THE TEXAS AND LOUISIANA GULF COASTS AND QUICKLY SWEEP EASTWARD INTO THE W ATLC BY EARLY WEDNESDAY. CARIBBEAN SEA... MOSTLY ZONAL WESTERLY UPPER LEVEL FLOW DOMINATES ACROSS MUCH OF THE CARIBBEAN AND WATER VAPOR IMAGERY INDICATES MODERATELY DRY AIR AND SUBSIDENCE IS PROVIDING FOR OVERALL STABLE ATMOSPHERIC CONDITIONS THIS MORNING. HOWEVER...A WEAK UPPER LEVEL SHORTWAVE TROUGH IS LOCATED OVER THE NE CARIBBEAN AND IS HELPING TO ENHANCE WIDELY SCATTERED LOW-TOPPED SHOWERS OVER THE BASIN EAST OF 70W. THIS AREA COINCIDES WITH STRONGER EASTERLY TRADES AS DEPICTED ON EARLIER OVERNIGHT WINDSAT AND ASCAT SCATTEROMETER PASSES. WINDS TO 20 KT WERE NOTED IN THOSE PASSES E OF 74W. THE RELATIVELY TRANQUIL CONDITIONS ACROSS A MAJORITY OF THE BASIN ARE EXPECTED OVER THE NEXT 24 TO 36 HOURS. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH AXIS EXTENDS FROM THE NEW ENGLAND STATES S-SW ALONG THE EASTERN U.S. SEABOARD AND SUPPORTS A COLD FRONT EXTENDING INTO THE SW NORTH ATLC NEAR 32N72W. THE FRONT CONTINUES SW TO THE FAR SOUTHERN FLORIDA PENINSULA NEAR FORT LAUDERDALE AND INTO THE SE GULF OF MEXICO AS A DISSIPATING STATIONARY FRONT. LOW-LEVEL CONVERGENCE EAST OF AND ALONG THE FRONT IS GENERATING WIDELY SCATTERED SHOWERS WITHIN 120 NM EAST OF THE FRONT AND IN THE VICINITY OF THE NW BAHAMAS FROM 24N-27N BETWEEN 75W-79W. THE FRONT IS FORECAST TO SHIFT NE OF 30N70W BY LATE SATURDAY INTO EARLY SUNDAY WITH LIGHT EASTERLY FLOW ONCE AGAIN ESTABLISHING ITSELF OVER THE SW NORTH ATLC W OF 70W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC THIS MORNING IS UNDER THE INFLUENCE OF A VERY BROAD SURFACE RIDGE ANCHORED BY A 1028 MB HIGH CENTERED NEAR 35N49W. A WEAK AND DISSIPATING COLD FRONT EXTENDS ALONG 30N BETWEEN 21W-34W AND CONTINUES TO BECOME MORE DIFFUSE AS IT MOVES SOUTHWARD. THIS FRONT IS SUPPORTED BY AN UPPER LEVEL LOW CENTERED WEST OF THE IBERIAN PENINSULA NEAR 36N17W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN