000 AXNT20 KNHC 040018 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI MAY 03 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N14W TO 06N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N18W TO THE EQUATOR NEAR 34W. WIDELY SCATTERED MODERATE CONVECTION IS S OF 02N BETWEEN 12W-19W. ISOLATED MODERATE CONVECTION IS S OF 05N BETWEEN 29W-39W. ...DISCUSSION... GULF OF MEXICO... GENERALLY DRY AIR AND WESTERLY UPPER LEVEL FLOW DOMINATE OVER THE GULF THIS EVENING...HOWEVER A VIGOROUS MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 36N94W OVER NE OKLAHOMA AND NW ARKANSAS THAT SUPPORTS A COLD FRONT ANALYZED INTO THE BASIN NEAR THE MISSISSIPPI DELTA REGION EXTENDING SOUTH TO THE YUCATAN PENINSULA NEAR 21N90W AND ALONG THE SOUTHERN MEXICO COAST TO 18N92W. WHILE THE ATMOSPHERE REMAINS FAIRLY DRY ALOFT...ONLY A FEW ISOLATED SHOWERS ARE OCCURRING N OF 27N WITHIN 60 NM EITHER SIDE OF THE FRONT. TO THE EAST...WATER VAPOR INDICATES A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH LOCATED ON THE SOUTHEASTERN PERIPHERY OF THE MAIN UPPER LEVEL LOW OVER THE CENTRAL CONUS. THIS SHORTWAVE SUPPORTS A BROAD AREA OF LOWER PRESSURE ACROSS THE EASTERN GULF...FLORIDA PENINSULA...AND A PORTION OF THE SW NORTH ATLC. SATELLITE IMAGERY AND SURFACE OBSERVATIONS NEAR THE FLORIDA PENINSULA COAST INDICATE A 1006 MB LOW IS CENTERED NEAR 28N80W WITH A SURFACE TROUGH EXTENDING S-SW ALONG 24N81W AND INTO THE NW CARIBBEAN SEA. A WEAKER SECONDARY 1009 MB LOW IS CENTERED NEAR 29N85W AND IS QUICKLY BECOMING ABSORBED INTO THE LOW TO THE EAST. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING IN THE VICINITY OF THE LOW ACROSS INLAND PORTIONS OF THE FLORIDA PENINSULA. ADDITIONAL ISOLATED SHOWERS ARE OCCURRING PRIMARILY E OF 85W. THE REMAINDER OF THE GULF WEST OF THE COLD FRONT IS UNDER THE INFLUENCE OF STRONG NORTHERLY WINDS AS SURFACE RIDGING BUILDS IN FROM THE SOUTHERN PLAINS AND ALONG THE EASTERN MEXICO COAST. THE AREA OF LOW PRESSURE OVER THE EASTERN GULF AND FLORIDA PENINSULA WILL BE SLOW TO MOVE NORTHWARD OVER THE WEEKEND AND IS FORECAST TO EVENTUALLY EXIT THE REGION BY WEDNESDAY OF NEXT WEEK. CARIBBEAN SEA... WEST-SOUTHWESTERLY MIDDLE TO UPPER LEVEL FLOW IS OVER MUCH OF THE CARIBBEAN THIS EVENING AS THE OVERALL SURFACE PRESSURE PATTERN REMAINS RELAXED AND SLIGHTLY MODIFIED FROM THE USUAL E- NE TRADE WIND FLOW. A LARGE AREA OF SURFACE TROUGHING IS ESTABLISHED OVER THE EASTERN GULF...FLORIDA PENINSULA...AND SW NORTH ATLC WHICH STRETCHES SOUTHWARD AND COVERS THE BASIN. WEAK SOUTHERLY WINDS ARE NOTED E OF 80W AS ISOLATED SHOWERS REMAIN POSSIBLE THROUGH THE OVERNIGHT HOURS. THE ONLY AREA OF SCATTERED SHOWERS AND TSTMS OCCURRING THIS EVENING IS LOCATED OVER THE SW CARIBBEAN S OF 16N W OF 78W...INCLUDING INLAND PORTIONS OF NICARAGUA AND COSTA RICA. AN APPROACHING COLD FRONT CURRENTLY OVER THE GULF OF MEXICO WILL PROVIDE FOR N-NW WINDS TO FILTER IN ACROSS THE WESTERN CARIBBEAN OVER THE WEEKEND. MEANWHILE WEAK SURFACE RIDGING WILL MAINTAIN ITS POSITION OVER THE EASTERN CARIBBEAN E OF 70W. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY WITH AXIS EXTENDING FROM OVER THE SE CONUS TO NEAR 29N79W. IT SUPPORTS A 1006 MB LOW CENTERED OFF THE FLORIDA PENINSULA COAST NEAR 28N80W. A STATIONARY FRONT REMAINS ANALYZED FROM THE LOW CENTER E-SE ALONG 25N74W TO 23N58W. A SURFACE TROUGH IS ALSO ANALYZED FROM THE LOW CENTER S-SW ACROSS THE SOUTHERN FLORIDA PENINSULA AND FLORIDA STRAITS NEAR 24N81W INTO THE NW CARIBBEAN SEA. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING OVER MUCH OF THE SW NORTH ATLC WATERS THIS EVENING REMAINING MOSTLY N OF 22N W OF 60W IN ASSOCIATION WITH THE FRONTAL BOUNDARY. FARTHER EAST...A BROAD AND COMPLEX MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 37N59W WITH SEVERAL WAVES OF ENERGY ROTATING AROUND THE MEAN CENTER. THIS UPPER LEVEL FEATURE SUPPORTS A VERY BROAD AREA OF SURFACE LOW PRESSURE CENTERED ON A 1009 MB LOW CENTERED NEAR 33N46W. A SURFACE TROUGH EXTENDS S-SW FROM THE LOW TO 26N50W TO 23N57W AND MARRIES UP WITH THE STATIONARY FRONT IN THE SW NORTH ATLC. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN A LARGE AREA TO THE EAST OF THE SURFACE TROUGH FROM 20N-32N BETWEEN 35W-50W...AND WITHIN 240 NM EITHER SIDE OF THE SURFACE TROUGH W OF 50W. FINALLY...A SURFACE RIDGE IS MAINTAINING CONTROL OVER THE EASTERN ATLC ANCHORED BY A 1020 MB HIGH CENTERED NEAR 26N29W. 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. $$ HUFFMAN