000 AXNT20 KNHC 081750 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED MAY 08 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 1745 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA-BISSAU NEAR 14N17W TO 7N22W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 7N22W TO 5N30W TO 2N40W TO THE COAST OF BRAZIL AT 1S46W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 90 NM OF THE ITCZ BETWEEN 33W-37W...AND FROM THE EQUATOR TO 4N W OF 48W TO THE COAST OF BRAZIL. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS ELSEWHERE ALONG THE ITCZ FROM 7N-2S BETWEEN 20W- 38W. ...DISCUSSION... GULF OF MEXICO... AS OF 1500 UTC...A 1021 MB HIGH IS OVER THE EAST-CENTRAL GULF OF MEXICO NEAR 27N84W PRODUCING MOSTLY FAIR WEATHER WITH THE EXCEPTION OF A PATCH OF BROKEN TO OVERCAST CLOUDS WITH WEAKENING ISOLATED SHOWERS AND THUNDERSTORMS WITHIN 60 NM OF 23N91W. LIGHT AND VARIABLE SURFACE WINDS OF 5-10 KT PREVAIL OVER THE GULF E OF 90W...WITH SE WINDS PICKING UP TO 10-15 KT W OF 90W TO THE TEXAS COAST. IN THE MID TO UPPER LEVELS...A TROUGH EXTENDS FROM A DEEP LAYERED CYCLONE OVER WEST VIRGINIA SOUTHWARD ALONG 85W/86W TO THE NW CARIBBEAN. UPPER LEVEL MOISTURE WAS STREAMING SE WEST OF THE TROUGH AXIS INTO THE BASE OF THE TROUGH...WHILE MODERATE SUBSIDENCE PREVAILED OVER FLORIDA AND THE GULF E OF THE TROUGH AXIS. THE SURFACE HIGH IS FORECAST TO MOVE E OVER FLORIDA AND ALLOW SE RETURN FLOW TO INCREASE OVER THE GULF W OF 90W WITH 15- 20 KT WINDS EXPECTED. CARIBBEAN SEA... A FAIRLY SHARP SURFACE TROUGH EXTENDS FROM S OF HAITI NEAR 17N73W TO THE COAST OF COLOMBIA NEAR 10N76W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 120 NM OF THE TROUGH...WITH THE GREATEST CONCENTRATION OF ACTIVITY NEAR THE COAST OF PANAMA. AS THIS TROUGH MOVES FURTHER WEST INTO THE EAST PACIFIC IN THE LONGER TERM EVOLVING ENVIRONMENTAL CONDITIONS ARE SETTING UP THE POTENTIAL FOR ADDITIONAL DEVELOPMENT OF THIS FEATURE. REFER TO THE MIATWDEP FOR ADDITION DETAILS. GENERALLY FAIR CONDITIONS PREVAIL ELSEWHERE OVER THE CARIBBEAN WITH 10-15 KT TRADEWINDS COMMON OVER AREAS E OF 80W AND THE TROUGH AXIS. LIGHTER AND MORE NORTHERLY WINDS OF AROUND 10 KT PREVAIL W OF THE TROUGH AXIS. IN THE MID TO UPPER LEVELS...THE BASE OF A NEGATIVELY TILTED TROUGH IS ENTERING THE NW CARIBBEAN WITH SOME MODERATE SUBSIDENCE NOTED. UPPER LEVEL DIFLUENCE E OF THE TROUGH WAS ENHANCING THE CONVECTIVE ACTIVITY ASSOCIATED WITH THE SURFACE TROUGH. THE WESTERN PORTION OF AN UPPER LEVEL HIGH IS OVER THE REMAINDER OF THE CARIBBEAN PRODUCING MODERATE SW UPPER LEVEL FLOW. SIGNIFICANT UPPER LEVEL MOISTURE AND BROKEN HIGH CLOUDS ARE NOTED OVER THE E CARIBBEAN. TRADE WINDS ARE FORECAST TO INCREASE TO NEAR NORMAL VALUES OF 15-20 KT OVER THE E CARIBBEAN IN THE NEXT 48 HOURS. ATLANTIC OCEAN... AS OF 1500 UTC...A SURFACE TROUGH WAS LOCATED N OF THE DOMINICAN REPUBLIC AND HAITI AND EXTENDED FROM 23N69W TO 20N71W MOVING WNW OVER THE SOUTHERN BAHAMAS AT 5-10 KT. SCATTERED SHOWERS AND THUNDERSTORMS ARE WITHIN 120-180 NM E OF THE TROUGH. ANOTHER SURFACE TROUGH WAS OVER THE FAR NW ATLC AND EXTENDED FROM 32N75W TO JUST N OF GRAND BAHAMAS ISLAND. A PAIR OF LOW PRES AREAS STRADDLE THE DISCUSSION AREA OVER THE CENTRAL ATLC NEAR 32N25W...1014 MB AND 32N33W...1016 MB RESPECTIVELY. A WEAKENING COLD FRONT EXTENDED FROM THE EASTERN LOW THROUGH 25N27W TO 20N35W AND TRANSITIONED TO A SHEAR LINE THROUGH 18N40W 17N50W TO JUST NE OF THE LEEWARD ISLANDS NEAR 19N62W. OVERCAST MULTILAYERED CLOUDS WITH SCATTERED SHOWERS WAS WITHIN 240 NM OF THE COLD FRONT N OF 27N. BROKEN TO OVERCAST LOW CLOUDS WITH ISOLATED WARM TOPPED SHOWERS WERE NOTED WITHIN 120 NM N OF THE SHEAR LINE BETWEEN 35W-60W. THE SHOWER AND THUNDERSTORM ACTIVITY BECAME MORE CONCENTRATED OVER THE SW ATLANTIC AT THE WESTERN EXTENT OF THE SHEAR LINE TO A SURFACE TROUGH N OF THE DOMINICAN REPUBLIC. A SURFACE TROUGH EXTENDED FROM THE WESTERN LOW NOTED ABOVE THROUGH 38N35W TO 27N39W AND WAS ACCOMPANIED BY LITTLE IN THE WAY OF SENSIBLE WEATHER. IN THE MID TO UPPER LEVELS...A SPRAWLING ANTICYCLONE IN THE DEEP TROPICS NEAR 10N57W DOMINATED MOST OF THE TROPICAL AND SUBTROPICAL ATLC WITH THE EXCEPTION OF THE NW PORTION N OF 20N W OF 70W AND THE SUBTROPICAL ATLC E OF 45W. BOTH AREAS WERE UNDER THE INFLUENCE OF UPPER LEVEL TROUGHS. 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. $$ COBB