000 AXNT20 KNHC 041036 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT MAY 04 2013 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 8N13W THEN ALONG 5N15W TO 4N20W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 3N27W 2N40W THEN S OF THE EQUATOR NEAR 48W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 3N TO JUST S OF THE EQUATOR BETWEEN 11W AND THE PRIME MERIDIAN. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 1N-6N BETWEEN 15W-37W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH EXTENDS FROM THE CENTRAL PLAIN STATES TO OVER THE LOWER MISSISSIPPI VALLEY INTO THE N GULF OF MEXICO N OF 27N SUPPORTING A WEAK COLD FRONT THAT AT 04/0900 UTC ENTERS THE GULF BETWEEN PENSACOLA AND PANAMA CITY FLORIDA TO 27N86W WHERE IT DISSIPATES TO THE N COAST OF THE YUCATAN PENINSULA NEAR 21N87W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 60 NM E OF THE FRONT WITH POSSIBLE ISOLATED SHOWERS WITHIN 75/90 NM W OF THE FRONT. NEAR ZONAL WESTERLY FLOW ALOFT COVERS THE REMAINDER OF THE GULF. WATER VAPOR IMAGERY SHOWS MODERATE TO STRONG SUBSTANCE WITH DRY STABLE AIR ALOFT OVER MOST OF THE GULF LIMITING SHOWER ACTIVITY ASSOCIATED WITH THE ABOVE FRONT. A WEAK SURFACE RIDGE COVERS THE W GULF ANCHORED BY A 1020 MB HIGH ALONG THE COAST OF MEXICO NEAR TUXPAN. THIS SURFACE FLOW IS BANKING LOW LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS OVER THE SW GULF S OF 22N W OF 90W. THE FRONT WILL WEAKEN AS IT SLOWLY MOVES E THROUGH TONIGHT. WINDS BEHIND THE FRONT WILL CONTINUE TO DIMINISH. ANOTHER COLD FRONT IS EXPECTED TO MOVE INTO THE NW GULF EARLY SUN THEN QUICKLY MOVE ACROSS THE N GULF THROUGH LATE SUN FOLLOWED BY FRESH TO STRONG WINDS. WINDS AND SEAS WILL DIMINISH OVER MUCH OF THE AREA MON THROUGH WED AS WEAK HIGH PRESSURE SETTLES OVER THE GULF WATERS. CARIBBEAN SEA... A BROAD UPPER RIDGE ANCHORED IN THE TROPICAL ATLC NEAR 8N45W EXTENDS A RIDGE AXIS INTO THE CARIBBEAN ACROSS THE WINDWARD ISLANDS OFF THE N COAST OF SOUTH AMERICA TO OVER CENTRAL AMERICA NEAR 13N84W. THIS IS GIVING MOST OF THE CARIBBEAN WESTERLY FLOW ALOFT WITH SCATTERED TO BROKEN HIGH CLOUDS S OF 19N W OF 83W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 90/120 NM OF LINE FROM 16N77W ACROSS HAITI TO 20N73W INCLUDING THE WINDWARD PASSAGE. THE MONSOON TROUGH EXTENDS ACROSS PANAMA AND COSTA RICA GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS S OF 13N W OF 80W TO INLAND OVER W PANAMA...COSTA RICA AND S NICARAGUA. THIS IS LEAVING THE REMAINDER OF THE NW CARIBBEAN WITH MOSTLY CLEAR SKIES THIS MORNING. FRESH TO STRONG NW WINDS OVER THE NW CARIBBEAN WILL DIMINISH THIS EVENING. OTHERWISE...LIGHT WINDS AND LOW SEAS WILL CONTINUE OVER THE REMAINDER OF THE CENTRAL AND W CARIBBEAN THROUGH MIDWEEK. TRADE WINDS ARE EXPECTED TO RETURN TO THE E CARIBBEAN TUE AND WED AS HIGH PRESSURE OVER THE CENTRAL ATLC BUILDS S AND SW. ATLANTIC OCEAN... A SHORTWAVE UPPER TROUGH EXTENDS FROM SE GEORGIA TO OFF THE FLORIDA COAST OVER THE BAHAMAS NEAR 26N78W SUPPORTING A 1004 MB SURFACE LOW THAT AT 04/0900 UTC IS CENTERED INLAND OVER FLORIDA NEAR 28N81W WITH A SURFACE TROUGH EXTENDING INTO THE W ATLC ALONG 26N79W TO THE N COAST OF CUBA NEAR 22N79W. A WARM FRONT EXTENDS E FROM THE SURFACE LOW ALONG 29N79W TO A STATIONARY FRONT NEAR 28N77W WHERE IT CONTINUES ALONG 23N67W TO 23N62W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE BETWEEN THE SURFACE TROUGH AND THE FRONTAL BOUNDARY N OF 24N. THIS SHORTWAVE UPPER TROUGH IS AMPLIFYING AN UPPER RIDGE THAT EXTENDS FROM E OF THE BAHAMAS NEAR 27N72W N-NW TO BEYOND 32N76W. THIS UPPER RIDGE IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 200 NM N OF THE FRONT. NEAR ZONAL WESTERLY FLOW ALOFT DOMINATES THE REMAINDER OF THE ATLC BASIN. AN UPPER TROUGH N OF THE DISCUSSION AREA IS SUPPORTING A REMNANT SURFACE TROUGH THAT EXTENDS FROM THE CENTRAL ATLC NEAR 31N42W ALONG 25N51W TO 23N61W. DENSE CLOUD COVER WITH POSSIBLE SHOWERS COVERS THE ATLC MOSTLY FROM 20N-30N BETWEEN 35W-71W. A SURFACE RIDGE COVERS THE E ATLC ANCHORED BY A 1020 MB HIGH NEAR 29N22W AND A 1021 MB HIGH OFF THE COAST OF PORTUGAL. THE COMBINATION OF HIGH PRESSURE BUILDING OVER THE NW ATLC AND THE LOW OVER FLORIDA WILL CONTINUE TO BRING STRONG TO GALE FORCE WINDS AND LARGE SEAS ACROSS MUCH OF THE W ATLC INTO EARLY TONIGHT. THE FLORIDA LOW IS FORECAST TO DRIFT TO NE FLORIDA TONIGHT THEN ACROSS SE GEORGIA SUN. THE FRONT WILL ALSO LIFT N THROUGH TONIGHT REACHING FROM NEAR 32N80W TO 25N73W SUN AND THE NE OF THE REGION BY MON WITH AS A WEAK PRESSURE PATTERN SETTLING IN ACROSS THE REGION THROUGH WED. A COLD FRONT WILL MOVE ACROSS THE FAR NW AND N CENTRAL ATLC LATE MON AND TUE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE AT THE REQUEST OF METEO-FRANCE AND THE METEROLOGICAL SERVICES OF HAITI AND THE DOMINICAN REPUBLIC...THE TROPICAL ANALYSIS AND FORECAST BRANCH (TAFB) WILL BEGIN PROVIDING...ON A TEMPORARY BASIS...A SEPARATE DETAILED SECTION WITHIN THE ATLANTIC TROPICAL WEATHER DISCUSSION (TWDAT). IT WILL COVER BOTH HAITI AND THE DOMINICAN REPUBLIC DUE TO THE SHARED GEOGRAPHY OF BOTH COUNTRIES ON THE ISLAND OF HISPANIOLA. THE SECTION BEGINS ON MAY 15 2013 AT 1800 UTC...2 PM EDT. IT WILL PROVIDE GUIDANCE FOR SIGNIFICANT WEATHER EVENTS THAT ARE EXPECTED TO IMPACT THE REGION THROUGH 48 HOURS...WITH THE FOCUS ON ASSESSING THE POTENTIAL FOR HEAVY RAINFALL. $$ PAW