000 AXNT20 KNHC 102342 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2245 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL NEAR 14N17W TO 7N22W. THE ITCZ BEGINS NEAR 7N22W AND CONTINUES ALONG 2N34W EQ43W 1S52W AND INTO NORTHERN BRAZIL. ISOLATED MODERATE CONVECTION IS FROM 2N-5N BETWEEN 26W-29W...AND FROM 3N-6N BETWEEN 35W-51W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING EXTENDS ACROSS THE GULF OF MEXICO TONIGHT ALONG WITH MOSTLY CLEAR SKIES. HOWEVER...SOME HEAVY SHOWERS AND THUNDERSTORMS ARE IMPACTING BOTH THE NORTH CENTRAL GULF AND SOUTH FLORIDA. AS OF 2100 UTC...A WEAK SURFACE TROUGH EXTENDS FROM SOUTHERN LOUISIANA NEAR 30N91W TO 27N95W. RADAR IMAGERY INDICATES NUMEROUS SHOWERS AND THUNDERSTORMS COVER SE LOUISIANA JUST EAST OF THE TROUGH. ISOLATED SHOWERS ARE WITHIN 30 NM EITHER SIDE OF THE SURFACE TROUGH TO THE SOUTH. ISOLATED SHOWERS ALSO CONTINUE TO THE EAST SOUTH OF THE FLORIDA PANHANDLE. A FEW LARGE CLUSTERS OF HEAVY SHOWERS/THUNDERSTORMS ARE ALSO ACROSS SOUTH CENTRAL FLORIDA. THE ACTIVITY IN THE NORTHERN GULF IS ALSO ENHANCED BY A SHORTWAVE UPPER TROUGH MOVING QUICKLY EAST ACROSS THE GULF COAST STATES AND IS CURRENTLY OVER MISSISSIPPI. THE REMAINDER OF THE BASIN IS COVERED BY AN UPPER LEVEL RIDGE CENTERED JUST SOUTH OF MEXICO. SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY ACROSS THE NORTHERN GULF AS A FRONT IS EXPECTED TO SWEEP ACROSS THE BASIN BEGINNING EARLY TOMORROW MORNING. CARIBBEAN SEA... THE UPPER LEVEL RIDGE ACROSS THE GULF OF MEXICO CONTINUES INTO THE FAR WESTERN GULF PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE NW PORTION. ACROSS THE SW CARIBBEAN...SURFACE TROUGHING IS STILL PRESENT ALONG 13N83W 10N81W. STRONG SHOWERS AND THUNDERSTORMS ARE WEST OF THE TROUGH ACROSS COSTA RICA AND PANAMA CONTINUING INTO THE EAST PACIFIC. THE TROUGH IS EXPECTED TO CONTINUE MOVING WESTWARD INTO THE EAST PACIFIC OVER THE WEEKEND. A SECOND SURFACE TROUGH IS MAINLY NORTH OF THE AREA BUT EXTENDS INTO HISPANIOLA NEAR 19N70W. THE TROUGH ALONG WITH DIFFLUENCE ALOFT AROUND AN UPPER TROUGH ALONG 70W IS SUPPORTING HEAVY SHOWERS AND THUNDERSTORMS ACROSS EASTERN HISPANIOLA AND PUERTO RICO. FLOODING IS POSSIBLE NEAR THE HEAVY SHOWERS. THE TROUGH IS EXPECTED TO MOVE EAST AND WILL BRING MOISTURE AWAY FROM HISPANIOLA AND THE OTHER NORTHERN CARIBBEAN ISLANDS. TRADEWIND FLOW OF 15-20 KT DOMINATES THE MAJORITY OF THE EASTERN AND CENTRAL CARIBBEAN BESIDES NEAR THE TROUGH IN THE SW PORTION. SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY ACROSS THE SW CARIBBEAN THROUGHOUT THE WEEKEND. ATLANTIC OCEAN... WEAK HIGH PRESSURE IS OVER THE FAR WESTERN ATLC AROUND A 1022 MB HIGH NEAR 30N74W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE EXTENDING FROM THE GULF OF MEXICO WITH AXIS CONTINUING JUST EAST OF FLORIDA. AN UPPER LEVEL TROUGH TO THE EAST ALONG 70W IS SUPPORTING A SURFACE TROUGH ALONG 25N69W 19N70W. A LARGE AREA OF SHOWERS AND POSSIBLE THUNDERSTORMS IS EAST OF THE TROUGH NORTH OF 21N BETWEEN 62W-69W. SOUTH OF 21N TWO CLUSTERS OF HEAVY THUNDERSTORMS ARE OVER EASTERN HISPANIOLA AND PUERTO RICO. THE TROUGH IS EXPECTED TO SLOWLY DRIFT EAST OVER THE NEXT SEVERAL DAYS BEFORE BEING SWEPT UP BY A FRONT. THE CENTRAL ATLC IS DOMINATED BY BROAD SURFACE RIDGING SUPPORTED BY AN UPPER LEVEL RIDGE ALONG 55W. AN UPPER LEVEL TROUGH COVERS THE EASTERN ATLC CENTERED AROUND AN UPPER LOW NEAR 33N37W. THE UPPER LOW SUPPORTS A WEAK 1016 MB SURFACE LOW NEAR 30N31W. SEVERAL SURFACE TROUGHS EXTEND FROM THE LOW CENTER. THE FIRST EXTENDS SOUTH TO 26N32W. NO SHOWERS ARE NEAR THE TROUGH. A SECOND TROUGH EXTENDS WEST TO NEAR 31N42W. SCATTERED SHOWERS ARE FROM 28N-31N BETWEEN 36W-40W. A THIRD SURFACE TROUGH EXTENDS TO THE NORTH AND OUT OF THE DISCUSSION AREA. THE REMAINDER OF THE EAST ATLC IS UNDER FAIR CONDITIONS. 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. $$ WALTON