000 AXNT20 KNHC 130600 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT THU AUG 13 2015 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 28W/29W...FROM 17N SOUTHWARD...MOVING WESTWARD 15 KNOTS. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION IS APPARENT IN SATELLITE IMAGERY. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 50W/51W FROM 15N SOUTHWARD MOVING WESTWARD 10 KNOTS. THE WAVE COINCIDES WITH A 700 MB TROUGH. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 10N TO 12N BETWEEN 50W AND 52W. A CARIBBEAN SEA TROPICAL WAVE IS ALONG 78W/79W FROM WESTERN JAMAICA TO PANAMA...MOVING WESTWARD 15 TO 20 KNOTS. THE WAVE COINCIDES WITH A 700 MB TROUGH. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION IS APPARENT IN SATELLITE IMAGERY. THIS WAVE IS MOVING THROUGH AN AREA OF LARGE-SCALE CYCLONIC WIND FLOW THAT SPANS THE CARIBBEAN SEA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF SENEGAL NEAR 14N17W...TO 12N20W 12N25W 09N33W 07N39W. THE ITCZ CONTINUES FROM 07N39W TO 07N44W 05N47W AND 06N50W. CONVECTIVE PRECIPITATION...ISOLATED MODERATE TO LOCALLY STRONG FROM 09N TO 12N BETWEEN AFRICA AND 20W...AND FROM 06N TO 10N BETWEEN 29W AND 57W. ...DISCUSSION... ...THE GULF OF MEXICO... LARGE-SCALE ANTICYCLONIC WIND FLOW IS SWEEPING ACROSS THE NORTHERN HALF OF THE GULF OF MEXICO...FROM 24N NORTHWARD. A STATIONARY FRONT PASSES THROUGH 31N80W IN THE ATLANTIC OCEAN...THROUGH THE FLORIDA PANHANDLE...TO THE COASTAL PLAINS/COASTAL WATERS OF ALABAMA AND MISSISSIPPI...THROUGH SOUTHERN LOUISIANA...INTO EAST TEXAS. CONVECTIVE PRECIPITATION...BROKEN TO OVERCAST MULTILAYERED CLOUDS AND ISOLATED MODERATE CONVECTIVE PRECIPITATION COVER THE AREA THAT IS FROM 27N TO 31N BETWEEN FLORIDA AND EASTERN SECTIONS OF TEXAS. A SURFACE RIDGE PASSES ACROSS ANDROS ISLAND...THROUGH THE STRAITS OF FLORIDA...TO A 1016 MB HIGH PRESSURE CENTER THAT IS NEAR 24N90W...TO THE COAST OF MEXICO ALONG 24N/25N. ...THE CARIBBEAN SEA AND HISPANIOLA... ONE MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 19N77W BETWEEN SOUTHEASTERN CUBA AND JAMAICA. A SECOND AND COMPARATIVELY WEAKER MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS TO THE SOUTH OF HAITI NEAR 17N72W. THESE TWO INDIVIDUAL CYCLONIC CIRCULATION CENTERS ARE EMBEDDED IN THE OVERALL LARGER-SCALE MIDDLE LEVEL TO UPPER LEVEL CYCLONIC WIND FLOW THAT SPANS THE CARIBBEAN SEA. A SURFACE TROUGH IS ALONG 70W/71W FROM 13N TO 17N. CONVECTIVE PRECIPITATION...ISOLATED MODERATE TO LOCALLY STRONG FROM 16N TO PUERTO RICO AND HISPANIOLA BETWEEN 65W AND 74W...AND FROM 17N TO 21N BETWEEN 76W AND 85W...AND FROM 12N TO 13N BETWEEN 82W AND 83W ALONG THE COAST OF NICARAGUA. RAINSHOWERS ARE POSSIBLE ELSEWHERE TO THE NORTHWEST AND NORTH OF THE LINE THAT RUNS FROM 17N64W TO 11N68W TO 12N75W TO 09N82W. SURFACE OBSERVATIONS FOR THE DOMINICAN REPUBLIC...FEW CUMULONIMBUS CLOUDS AND OTHER SCATTERED LOW LEVEL CLOUDS ARE BEING OBSERVED IN SANTO DOMINGO. FEW LOW LEVEL CLOUDS ARE IN LA ROMANA. SCATTERED LOW LEVEL CLOUDS AND SCATTERED MIDDLE LEVEL CLOUDS ARE IN PUNTA CANA. FEW LOW LEVEL CLOUDS AND SCATTERED HIGH LEVEL CLOUDS ARE IN SANTIAGO. FEW LOW LEVEL CLOUDS ARE BEING OBSERVED IN PUERTO PLATA. THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT THE CURRENT 17N72W CYCLONIC CIRCULATION CENTER WILL MOVE NORTHWESTWARD TO 20N81W. SOUTHERLY WIND FLOW WILL COVER HISPANIOLA FOR MOST OF THE FIRST 24 HOURS OF THE 48-HOUR FORECAST PERIOD THAT STARTS ON 13/0000 UTC. THE CYCLONIC CIRCULATION CENTER EVENTUALLY WILL MOVE TO 20N81W...AND THEN IT WILL DISSIPATE BY THE END OF THE 48-HOUR FORECAST PERIOD. THE GFS MODEL FORECAST FOR 500 MB SHOWS THAT INVERTED TROUGHS WILL MOVE ACROSS HISPANIOLA FOR THE FIRST 24 HOURS OF THE 48-HOUR FORECAST PERIOD. SOUTHEASTERLY WIND FLOW EVENTUALLY COVERS THE ENTIRE AREA FOR DAY TWO. THE GFS MODEL FORECAST FOR 700 MB SHOWS THAT INVERTED TROUGHS WILL MOVE WESTWARD ACROSS HISPANIOLA FOR THE NEXT 48 HOURS. EXPECT VARIATIONS IN THE WIND DIRECTION. THE ATLANTIC OCEAN... A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N79W TO 30N79W. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS TO THE NORTH AND NORTHWEST OF THE LINE THAT RUNS FROM 30N NORTHWARD IN FLORIDA TO 30N80W BEYOND 32N78W. THE TROUGH SUPPORTS A COLD FRONT THAT PASSES THROUGH 32N76W TO 31N80W. A STATIONARY FRONT CONTINUES WESTWARD ALONG 30N/31N IN THE GULF COASTAL PLAINS OF THE U.S.A. CONVECTIVE PRECIPITATION...ISOLATED MODERATE TO LOCALLY STRONG FROM 29N NORTHWARD BETWEEN 64W AND 80W...AND WITHIN A 30 NM RADIUS OF 27N79W. A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM A 25N52W CYCLONIC CIRCULATION CENTER...TO A 24N63W CYCLONIC CIRCULATION CENTER. A SURFACE TROUGH IS ALONG 31N31W 26N39W 29N47W. CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE FROM 24N NORTHWARD BETWEEN 46W AND 66W. AN UPPER LEVEL TROUGH EXTENDS FROM A 31N24W CYCLONIC CIRCULATION CENTER...TO 25N26W. COMPARATIVELY DRIER AIR IN SUBSIDENCE SURROUNDS THE CYCLONIC CENTER AND TROUGH. A SURFACE RIDGE PASSES THROUGH 32N60W TO 29N66W...TO ANDROS ISLAND IN THE BAHAMAS...THROUGH THE STRAITS OF FLORIDA...TO A 1016 MB HIGH PRESSURE CENTER THAT IS NEAR 24N90W...TO THE COAST OF MEXICO ALONG 24N/25N. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT