000 AXNT20 KNHC 131104 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 11N15W TO 6N17W. THE ITCZ BEGINS FROM 6N17W AND CONTINUES ALONG 2N30W EQ35W EQ49W. ISOLATED MODERATE CONVECTION IS FROM 5N-7N BETWEEN 21W-25W. SCATTERED MODERATE CONVECTION IS FROM EQ-5N BETWEEN 40W- 52W. ...DISCUSSION... GULF OF MEXICO... A COLD FRONT CONTINUES TO MOVE SLOWLY THROUGH THE GULF OF MEXICO CURRENTLY EXTENDING ACROSS CENTRAL FLORIDA FROM 28N80W 26N89W WHERE IT BECOMES STATIONARY ALONG 24N93W 22N94W...AND DISSIPATES ALONG 20N95W 19N97W...AS OF 0900 UTC. A PRE-FRONTAL TROUGH IS IN THE SW GULF ALONG 22N93W 18N93W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS EXTEND UP TO 300 NM NW OF THE FRONT WEST OF 90W. ISOLATED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE AXIS ELSEWHERE. A LARGE CLUSTER OF CONVECTION IS ALSO OVER THE YUCATAN PENINSULA AND SOUTHERN MEXICO FROM 17N-20N BETWEEN 89W- 95W. MAINLY NE SURFACE WINDS OF 10-15 KT ARE NORTH OF THE FRONT WITH E-NE FLOW TO THE SOUTH. THE SOUTHERN PORTION OF THE FRONT WILL REMAIN STATIONARY OVER THE SW GULF AND CONTINUE TO DISSIPATE WHILE THE NE PORTION CONTINUES TO MOVE EASTWARD. MOISTURE WILL REMAIN OVER THE WESTERN GULF AND LIFT NORTH AS RETURN FLOW BUILDS AND SURFACE RIDGING RETURNS TO THE BASIN. ALOFT...SOUTHWESTERLY FLOW DOMINATES BETWEEN AN UPPER LEVEL TROUGH ACROSS WESTERN MEXICO AND AN UPPER LEVEL RIDGE ACROSS THE WESTERN CARIBBEAN. CARIBBEAN SEA... MOSTLY FAIR CONDITIONS SPREAD ACROSS THE CARIBBEAN DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE ACROSS THE WESTERN CARIBBEAN ALONG 80W...AND AN UPPER LEVEL TROUGH ACROSS THE EASTERN CARIBBEAN ALONG 17N61W TO 11N68W. ONLY A SMALL CLUSTER OF SHOWERS AND POSSIBLE THUNDERSTORMS IS ALONG THE NORTHERN COAST OF PANAMA...AND THE SOUTHERN COAST OF COSTA RICA. A FEW POSSIBLE ISOLATED SHOWERS ARE ALSO MOVING THROUGH THE NE CARIBBEAN...AND SOUTH OF HAITI FROM 18N-19N BETWEEN 73W-76W. TRADEWIND FLOW OF 10-15 KT DOMINATES THE MAJORITY OF THE AREA EXCEPT FOR 20-25 KT WINDS OVER THE SW CARIBBEAN AND AROUND THE COAST OF COLOMBIA. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH NORTH OF THE DISCUSSION AREA SUPPORTS A COLD FRONT THAT CLIPS THE CORNER OF THE AREA ALONG 32N76W TO 28N81W...AS OF 0900 UTC. SCATTERED SHOWERS ARE UP TO 75 NM EAST OF THE AXIS. UPPER LEVEL RIDGING COVERS THE AREA IMMEDIATELY TO THE EAST OF THE UPPER TROUGH SUPPORTING A WEAK 1017 MB HIGH NEAR 27N75W. ANOTHER UPPER TROUGH EXTENDS ALONG 30N47W TO 17N61W SUPPORTING A 1014 MB SURFACE LOW NEAR 23N69W. A SURFACE TROUGH EXTENDS SOUTH OF THE LOW CENTER TO NEAR 20N70W. A FEW LOW-LEVEL CLOUDS AND POSSIBLE ISOLATED SHOWERS ARE NEAR THE LOW CENTER. DIFFLUENCE ALOFT AROUND THE EAST SIDE OF THE UPPER TROUGH IS SUPPORTING A WIDE AREA OF ISOLATED SHOWERS 14N-26N BETWEEN 44W- 59W. BROAD SURFACE RIDGING DOMINATES THE REMAINDER OF THE CENTRAL AND EASTERN ATLC ANCHORED BY A 1038 MB HIGH NW OF THE AZORES ISLANDS NEAR 42N34W. THE RIDGE IS PROVIDING FAIR CONDITIONS ACROSS THIS AREA. THE RIDGE IS SUPPORTED BY BROAD UPPER RIDGING COVERING THE TROPICAL ATLC. A HORIZONTALLY ALIGNED UPPER TROUGH IS JUST NORTH OF THE AREA ALONG 36N EAST OF 44W SUPPORTING A WEAK SURFACE TROUGH THAT EXTENDS INTO THE RIDGE ALONG 30N21W 29N29W. NO SHOWERS ARE ASSOCIATED WITH THE TROUGH. 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