000 AXNT20 KNHC 101737 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI MAY 10 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA-BISSAU NEAR 12N16W TO 5N23W. THEN...THE INTERTROPICAL CONVERGENCE ZONE AXIS CONTINUES FROM 5N23W TO 2N40W TO THE COAST OF BRAZIL AT EQ50W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED FROM 2N TO THE COAST OF AFRICA BETWEEN THE PRIME MERIDIAN AND 12N. SCATTERED MODERATE CONVECTION IS FROM 3N TO 6N BETWEEN 22W AND 27W AND FROM 4N TO 6N W OF 35W. ...DISCUSSION... GULF OF MEXICO... A 1022 MB HIGH PRES LOCATED NEAR 30N73W EXTENDS A RIDGE E TO W ACROSS THE NORTHERN GULF WATERS PRODUCING A MODERATE TO FRESH SOUTHERLY WIND FLOW ACROSS THE REGION. LOWER PRESSURES ARE NOTED OVER THE WESTERN GULF AHEAD OF THE NEXT COLD FRONT FORECAST TO MOVE OFF THE LOUISIANA AND TEXAS COAST EARLY SAT. THE FRONT WILL REACH FROM THE WESTERN FLORIDA PANHANDLE TO 21N97W ON SAT NIGHT...AND WEAKEN FROM THE FLORIDA BIG BEND TO THE BAY OF CAMPECHE ON SUN. A BAND OF SHOWERS AND THUNDERSTORMS WILL LIKELY BE ASSOCIATED WITH THE FRONT. CURRENTLY...SHOWERS AND TSTMS ARE DEVELOPING AHEAD OF THE FRONT OVER SE LOUISIANA AND ALONG THE COST OF TEXAS IN ASSOCIATION WITH A MOIST ONSHORE FLOW OVER THE AREA. ALOFT... AN UPPER LEVEL RIDGE...CENTERED ON AN ANTICYCLONE NEAR THE GULF OF TEHUANTEPEC...COVERS THE GULF WITH AXIS NEAR 90W. UPPER LEVEL DIFFLUENCE IS HELPING TO INDUCE THE CONVECTION OVER TEXAS AND LOUISIANA. MID/UPPER LEVEL MOISTURE DOMINATES MUCH OF THE REGION. CARIBBEAN SEA... AN UPPER LEVEL TROUGH CONTINUES TO BE THE MAIN WEATHER PLAYER ACROSS THE REGION. THE TROUGH HAS MOVED E OF FLORIDA AND THE AXIS IS NEAR 73W/74W ACROSS THE SW N ATLC AND THE CARIBBEAN SEA. DRY AIR ALOFT IS ACROSS THE WESTERN CARIBBEAN ON THE WEST SIDE OF THE TROUGH...BUT ABUNDANT MID/UPPER LEVEL MOISTURE IS NOTED AHEAD OF THE TROUGH OVER THE EASTERN CARIBBEAN UNDER THE INFLUENCE OF A SW WIND FLOW ALOFT. THIS UPPER LEVEL TROUGH CONTINUES TO SUPPORT A SURFACE TROUGH THAT NOW EXTENDS FROM 26N69W TO DOMINICAN REPUBLIC NEAR 19N70W. THE STRONGEST CONVECTION ASSOCIATED WITH THIS FEATURE IS N OF HISPANIOLA. SOME DRY AIR IS MAKING ITS WAY TOWARD HISPANIOLA...RESULTING IS LESS SHOWER AND TSTM ACTIVITY THAN THE PREVIOUS DAYS WHEN THE TROUGH AXIS WAS WEST OF THE ISLAND. COMPUTER MODEL SHOWS MOISTURE ASSOCIATED WITH THIS TROUGH AFFECTING PUERTO RICO AND US/UK VIRGIN ISLANDS ON SAT. CONVECTION CONTINUES TO FLARE UP OVER THE SW CARIBBEAN IN ASSOCIATION WITH THE COLOMBIAN/PANAMANIAN LOW. THERE IS A CLUSTER OF MODERATE TO STRONG CONVECTION S OF 10N E OF 78W TO THE COAST OF COLOMBIA. ANOTHER CLUSTER OF SIMILAR CONVECTION IS ALSO NOTED S OF 10N W OF 80W. THE MIMIC-TPW ANIMATION SHOWS A GOOD SURGE OF MOISTENED AIR OVER THE SW CARIBBEAN. SCATTEROMETER DATA SHOW FRESH TO STRONG TRADE WINDS ACROSS THE SOUTH CENTRAL CARIBBEAN WHILE MODERATE TO FRESH TRADES PREVAIL ELSEWHERE. THIS REGIMEN WILL PERSIST OVER THE NEXT SEVERAL DAYS AS HIGH PRES REMAINS STRONG NE OF AREA. MOISTURE WITH A SHEAR AXIS OVER THE NE CARIBBEAN IS EXPECTED TO SHIFT SOUTH ACROSS THE LESSER ANTILLES SAT. NE WINDS OF 15 TO 20 KT ARE STILL NOTED N OF THE SHEAR AXIS. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH EXTENDS FROM 31N72W TO THE SE BAHAMAS AND IS SUPPORTING THE AFOREMENTIONED SURFACE TROUGH THAT GOES FROM 26N69W TO DOMINICAN REPUBLIC. A LARGE AREA OF SHOWERS AND THUNDERSTORMS IS AHEAD OF THE TROUGH COVERING FROM 20N-30N BETWEEN 65W-70W. BROAD SURFACE RIDGING COVERS THE REMAINDER OF THE WESTERN AND CENTRAL ATLC SUPPORTED BY AN UPPER LEVEL RIDGE ALONG 60W. BROAD UPPER TROUGHING COVERS THE EASTERN ATLC WITH AXIS NEAR 35W. THE UPPER TROUGH SUPPORTS A WEAK 1016 MB SURFACE LOW NEAR 31N30W. A SURFACE TROUGH EXTENDS FROM THE LOW CENTER TO NEAR 24N33W. NO SHOWER ACTIVITY IS NEAR THE TROUGH. A SECOND WEAK LOW PRES IS NEAR 31N43W. VISIBLE SATELLITE IMAGERY SHOWS A SWIRL OF LOW CLOUDS ASSOCIATED WITH THE LOW CENTER. SCATTERED SHOWERS ARE IN BANDS TO THE NE AND SE OF LOW CENTER. AN AREA OF SAHARAN DUST IS NOTED ON VIS SATELLITE IMAGERY REACHING 35W... AND IS CONFIRMED BY THE SAHARAN AIR LAYER TRACKING PRODUCT FROM UW-CIMSS. MOISTURE NEAR THE SHEAR AXIS THAT EXTENDS ALONG 20N36W TO 16N50W TO 16N50W TO 19N67W IS DIMINISHING. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE AT THE REQUEST OF METEO-FRANCE AND THE METEOROLOGICAL 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. $$ GR