000 AXNT20 KNHC 141757 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE MAY 14 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 12N16W TO 9N21W. THE ITCZ BEGINS FROM 9N21W AND CONTINUES THROUGH 04N30W TO 03N40W TO 01N53W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM SOUTH OF THE AXIS BETWEEN 26W- 32W...AND ALSO WITHIN 210 NM N OF THE AXIS BETWEEN 38W-43W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 180 NM N OF THE ITCZ AXIS W OF 47W. ...DISCUSSION... GULF OF MEXICO... A 1025 MB HIGH CENTER IS LOCATED OVER SE LOUISIANA AS OF 1500 UTC WITH ASSOCIATED RIDGING BUILDING E ACROSS THE AREA. THE PREVIOUS MENTIONED COLD FRONT OVER THE SE AND S PORTIONS OF THE GULF WITH STATIONARY FRONT OVER THE SW GULF IS DISSIPATING AS THE RIDGE BUILDS ACROSS THE AREA. BUOY AND SURFACE OBSERVATIONS DEPICT GENERALLY ANTI-CYCLONIC FLOW N OF THE DECAYING FRONTAL BOUNDARY. A SURFACE TROUGH IS IN THE SW GULF AND EASTERN BAY OF CAMPECHE ROUGHLY ALONG 93W S OF 22N. WIDELY SCATTERED SHOWERS ARE POSSIBLE WITHIN 120 NM W AND 60 NM E OF THE TROUGH. SCATTERED TO BROKEN LOW CLOUDS WITH ISOLATED SHOWERS ARE ELSEWHERE W OF THE TROUGH...AND ALSO FROM 22N TO 28N W OF 93W. OVER THE REMAINDER OF THE GULF...LATEST VIS SATELLITE IMAGERY SHOWS MOSTLY CLEAR SKIES UNDER THE AFOREMENTIONED HIGH PRES ALONG WITH DRY AIR ALOFT AS SEEN IN WATER VAPOR IMAGERY. WATER VAPOR IMAGERY ALSO SHOWS UPPER LEVEL RIDGING OVER THE WESTERN AND CENTRAL GULF PORTIONS...WHILE A DEEP LAYER TROUGH IS NOTED OVER THE W ATLANTIC. THE FLOW PATTERN BETWEEN THESE FEATURES IS NWLY ...EXCEPT W-NW ACROSS THE UPPER RIDGE. THE RIDGE IS FORECAST TO SHIFT E OF THE AREA BY THU WITH ZONAL FLOW SETTING UP ACROSS THE AREA. THE SURFACE COLD FRONT WILL CONTINUE TO DISSIPATE THROUGH EARLY WED AS IT SLOWLY MOVES S TOWARDS CUBA...AND AS HIGH PRES RIDGING EXTENDS E TO W OVER THE FAR NORTHERN GULF. THE TROUGH ALONG 93W WILL WEAKEN THROUGH WED EVENING AS IT MOVES INLAND MEXICO. CARIBBEAN SEA... VERY WELL PRONOUNCED HIGH PRES IN THE UPPER LEVELS OF THE ATMOSPHERE THROUGHOUT THE CARIBBEAN CONTINUES TO RESULT IN MODERATE SUBSIDENCE DRY AND DRY CONDITIONS ALOFT. AN UPPER LEVEL TROUGH IS JUST E OF THE CARIBBEAN. AS A RESULT...DEEP LAYER MOISTURE REMAINS VERY SUPPRESSED ACROSS THE AREA WITH ONLY ISOLATED SHOWERS MOVING TO THE WNW N OF 14N E OF 72W...AND SIMILAR SHOWERS MOVING SW TO THE N OF 14N W OF 79W. MORE CONCENTRATED MOISTURE IS EVIDENT OVER HAITI AND OVER PORTIONS OF THE DOMINICAN REPUBLIC WHERE A SURFACE TROUGH EXISTS. THIS MOISTURE SHOULD COMBINE WITH AFTERNOON HEATING TO PRODUCE SCATTERED SHOWERS AND TSTMS ACROSS MUCH OF HISPANIOLA FOR THE REST OF TODAY...AND AGAIN WED AND THU AS ADDITIONAL MOISTURE ASSOCIATED WITH THE TAIL END OF THE WEAKENING WESTERN ATLC COLD FRONT APPROACHES EASTERN CUBA AND HISPANIOLA. ELSEWHERE LITTLE OVERALL CHANGE IS EXPECTED. ATLANTIC OCEAN... WATER VAPOR IMAGERY SHOWS A DEEP LAYER TROUGH EXTENDING FROM 32N70W SW TO NEAR 24N79W. THE TROUGH SUPPORTS A SURFACE COLD FRONT THAT STRETCHES FROM NEAR 32N66W SW TO 26N73W TO ANDROS ISLANDS WHERE IT BEGINS TO DISSIPATE TO THE STRAITS OF FLORIDA. A PRE-FRONTAL SURFACE TROUGH IS EAST OF THE FRONT FROM 32N65W TO 23N78W. ANOTHER SURFACE TROUGH IS ROUGHLY ALONG 70W S OF 23N TO ACROSS THE CENTRAL PORTION OF THE DOMINICAN REPUBLIC. SCATTERED SHOWERS AND THUNDERSTORMS ARE WITHIN 240 NM E OF THE PRE-FRONTAL TROUGH N OF 26N...WHILE SCATTERED SHOWERS AND ISOLATED TSTMS ARE ELSEWHERE WITHIN 210 NM E OF THE TROUGH. A RIDGE/TROUGH/RIDGE PATTERN REMAINS OVER THE REMAINDER OF THE UPPER LEVELS ACROSS THE BASIN. THE FIRST UPPER RIDGE EXTENDS FROM ABOUT 32N55W SSW TO 25N57W TO 18N58W. THE UPPER TROUGH IS CONNECTED TO AN UPPER LEVEL LOW N OF THE AREA NEAR 32N42W MOVING SW...AND STRETCHES THROUGH 25N47W AND FURTHER SW TO JUST E OF THE WINDWARD ISLANDS NEAR 10N60W. THE SECOND UPPER RIDGE IS BROAD AND COVERS THE MAJORITY OF THE TROPICAL ATLC...AND IS CENTERED NEAR 12N23W. AT THE SURFACE...A TROUGH INDUCED BY THE UPPER LEVEL LOW LIES ALONG 29N41W 24N44W. DIVERGENCE ALOFT E OF THE UPPER LOW IN COMBINATION WITH THE SURFACE TROUGH IS HELPING TO SET OFF DEEP LAYER MOISTURE WITH SCATTERED SHOWERS AND ISOLATED TSTMS FROM 25N TO 31N BETWEEN 30W-42W. ELSEWHERE ACROSS THE AREA...HIGH PRESSURE THROUGH ALL LEVELS OF THE ATMOSPHERE IS MAINTAINING GENERALLY FAIR CONDITIONS. SCATTERED SHOWERS ARE ALONG AND NEAR THE TROUGH THAT IS ALONG 70W. THE COLD FRONT MENTIONED ABOVE IS FORECAST TO WEAKEN AND SHEAR OFF W OF ABOUT 65W AS IT PUSHES EASTWARD THROUGH THU...WITH LINGERING MOISTURE TO BE AROUND THE VICINITY OF EASTERN CUBA...THE SE BAHAMAS AND COMBINING WITH THAT ALREADY IN PLACE OVER HISPANIOLA. 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. $$ AGUIRRE