000 AXNT20 KNHC 131734 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON MAY 13 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 NEAR 10N14W TO 6N17W. THE ITCZ BEGINS FROM 6N17W AND CONTINUES ALONG 2N30W EQ40W 1N50W. SCATTERED MODERATE CONVECTION IS WITHIN 50 NM SE OF LINE FROM 7N23W TO 5N28W. SIMILAR CONVECTION IS NOTED FROM 2N TO 5N W OF 45W TO THE COAST OF BRAZIL AND FRENCH GUIANA. ...DISCUSSION... GULF OF MEXICO... A COLD FRONT CONTINUES TO MOVE SLOWLY THROUGH THE GULF OF MEXICO CURRENTLY EXTENDING ACROSS CENTRAL FLORIDA FROM 28N81W TO 25.5N90W WHERE IT BECOMES STATIONARY ALONG 24N94W TO THE BAY OF CAMPECHE NEAR 19N95W. A PRE-FRONTAL TROUGH PERSISTS OVER THE EASTERN BAY OF CAMPECHE ALONG 92W FROM 19N TO 23N. SCATTERED SHOWERS AND TSTMS ARE ASSOCIATED WITH THE STATIONARY PORTION OF THE FRONT. ISOLATED SHOWERS ARE NOTED ELSEWHERE ALONG THE FRONTAL BOUNDARY. THE COLD PORTION OF THE FRONT WILL CONTINUE TO MOVE SE REACHING SOUTH FLORIDA LATER TODAY WHILE THE STATIONARY PART IS FORECAST TO DISSIPATE OVER THE BAY OF CAMPECHE OVER THE NEXT COUPLE OF DAYS. MODERATE TO FRESH NE WINDS FOLLOW THE FRONT. GENTLE TO MODERATE EASTERLY WINDS ARE SEEN AHEAD OF THE FRONT...AND SLIGHTLY INCREASE NEAR THE PRE-FRONTAL TROUGH. MOISTURE WILL REMAIN OVER THE WESTERN GULF AND LIFT NORTH AS RETURN FLOW BUILDS AND SURFACE RIDGING ESTABLISHES ACROSS THE GULF WATERS. ALOFT...SOUTHWESTERLY FLOW DOMINATES BETWEEN AN UPPER LEVEL TROUGH ACROSS CENTRAL TEXAS AND NW MEXICO AND AN UPPER LEVEL RIDGE CENTERED ACROSS THE WESTERN CARIBBEAN. CARIBBEAN SEA... MOSTLY FAIR CONDITIONS PREVAIL ACROSS THE BASIN WITH THE TYPICAL TRADE WIND SHOWERS AND SOME HIGH CLOUDS OVER THE NW CARIBBEAN AND WEST-CENTRAL CUBA DUE TO STRONG WESTERLY WINDS ALOFT. TRADE WIND FLOW OF 10-15 KT DOMINATES THE MAJORITY OF THE EASTERN AND CENTRAL CARIBBEAN WITH WINDS OF 20 TO 25 KT NEAR THE COAST OF COLOMBIA. THIS REGIMEN IS FORECAST TO PERSIST OVER THE NEXT SEVERAL DAYS. A WEAK COLD FRONT WILL PASS E ACROSS CUBA AND THE CARIBBEAN WATERS N OF 20N W OF HISPANIOLA TONIGHT AND TUE. MAINLY MODERATE NE WINDS WILL FOLLOW THE FRONT. IN THE UPPER LEVELS...AN ANTICYCLONE IS CENTERED OVER THE SW CARIBBEAN AND EXTENDS A RIDGE NE THROUGH HISPANIOLA INTO THE WESTERN ATLANTIC. MODERATE TO STRONG UPPER LEVEL SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY E OF 75W...INCLUDING HISPANIOLA...PUERTO RICO... THE VIRGIN ISLANDS AND MOST OF THE LESSER ANTILLES. THIS WEATHER PATTERN IS LIMITING THE DEVELOPMENT OF SHOWER AND TSTM ACTIVITY OVER THOSE ISLANDS. AN UPPER LEVEL TROUGH CROSSES THE SE CARIBBEAN STRETCHING FROM NEAR MARTINIQUE TO NORTHERN VENEZUELA NEAR 10N68W. ABUNDANT MID/UPPER LEVEL MOISTURE IS AHEAD OF THE TROUGH AXIS AFFECTING NE VENEZUELA AND TRINIDAD AND TOBAGO. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH OVER THE EASTERN UNITED STATES SUPPORTS A COLD FRONT THAT EXTENDS FROM A 1013 MB LOW PRES NEAR 33N75W TO CENTRAL FLORIDA...JUST N OF LAKE OKEECHOBEE...INTO THE GULF OF MEXICO. THE FRONT WILL MOVE SOUTH AND THROUGH SOUTH FLORIDA THIS AFTERNOON INTO EARLY THIS EVENING. CURRENTLY...DOPPLER RADAR SHOWS ONLY ISOLATED SHOWERS ALONG THE FRONTAL BOUNDARY OVER CENTRAL FLORIDA. THE LOW PRES LOCATED EAST THE BAHAMAS DURING THE PREVIOUS DAYS IS NOW WEAKENING. CURRENTLY...IT IS CENTERED NEAR 23N69W. A TROUGH EXTENDS FROM 28N70W TO THE LOW CENTER THEN CONTINUES SOUTH TO THE MONA PASSAGE. A WEAK SWIRL OF LOW CLOUDS IS RELATED TO THE LOW PRES FORECAST TO GRADUALLY DISSIPATE ALONG THE TROUGH LATER TODAY...THEN THE TROUGH WILL MERGE WILL THE AFOREMENTIONED COLD FRONT. UPPER LEVEL RIDGING COVERS THE AREA IMMEDIATELY TO THE EAST OF THE UPPER TROUGH OVER U.S. EXTENDING FROM HISPANIOLA TO BEYOND 31N62W. ANOTHER UPPER TROUGH EXTENDS OVER THE CENTRAL ATLC FROM 31N45W TO 17N59W TO THE SE CARIBBEAN. STRONG UPPER LEVEL SUBSIDENCE IS SEEN ON THE WEST SIDE OF THE TROUGH WHILE SWLY WINDS AHEAD OF THE TROUGH ARE TRANSPORTING A GOOD AMOUNT OF MID/UPPER LEVEL MOISTURE FROM NE VENEZUELA ACROSS THE CENTRAL ATLC. VIS SATELLITE IMAGERY INDICATES A PLUME OF HIGH CLOUDS ASSOCIATED WITH THESE WINDS. BROAD SURFACE RIDGING DOMINATES THE REMAINDER OF THE CENTRAL AND EASTERN ATLC ANCHORED BY A 1038 MB HIGH PRES SITUATED NW OF THE AZORES NEAR 42N36W. THE RIDGE IS PROVIDING MOSTLY FAIR CONDITIONS ACROSS THIS AREA. THE RIDGE IS SUPPORTED BY BROAD UPPER RIDGING COVERING THE TROPICAL ATLC. ONCE AGAIN...AN AREA OF SAHARAN DUST IS OBSERVED ON VIS AND SAHARAN AIR LAYER SATELLITE IMAGERY REACHING 50W. THE REMNANTS OF A SHEAR AXIS IS STILL EVIDENT OF VIS SATELLITE IMAGERY ACROSS THE TROPICAL ATLC JUST N OF THE AREA OF SAHARAN DUST. 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