000 AXNT20 KNHC 151142 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED AUG 15 2012 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 1115 UTC. ...SPECIAL FEATURE A CENTRAL ATLANTIC OCEAN SURFACE TROUGH IS ALONG 30N54W... TO A 1014 MB LOW PRESSURE CENTER THAT IS NEAR 26N54W...TO 21N58W. THIS TROUGH ORIGINATED AS THE NORTHERN PART OF THE CURRENT 60W TROPICAL WAVE. SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION COVERS THE ATLANTIC OCEAN FROM 27N TO 29N BETWEEN 53W AND 55W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE ELSEWHERE FROM 23N TO 31N BETWEEN 49W AND 57W. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES NORTH-NORTHWESTWARD 13 KNOTS TODAY...AND THEN IT TURNS NORTHEASTWARD BY THURSDAY. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 21W/22W TO THE SOUTH OF 21N...BASED ON LONG-TERM SATELLITE IMAGERY. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE FROM 9N TO 24N BETWEEN 14W AND 26W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 39W FROM 20N TO 10N... BASED ON LONG-TERM SATELLITE IMAGERY. RAINSHOWERS ARE POSSIBLE FROM 10N TO 20N BETWEEN 35W AND 40W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 60W TO THE SOUTH OF 20N...REACHING THE VENEZUELA/GUYANA BORDER...BASED ON SATELLITE IMAGERY. ISOLATED MODERATE CONVECTIVE PRECIPITATION IS FROM 9N TO 22N BETWEEN 57W AND 63W. A MIDDLE LEVEL TO UPPER LEVEL ATLANTIC OCEAN INVERTED TROUGH IS ALONG 22N58W 15N59W...BEYOND 7N59W IN NORTHERN GUYANA. A TROPICAL WAVE IS ALONG 86W...FROM 23N IN THE YUCATAN CHANNEL BEYOND WESTERN NICARAGUA. SCATTERED TO NUMEROUS STRONG CONVECTIVE PRECIPITATION HAS MOVED ACROSS EL SALVADOR AND ITS COASTAL WATERS FROM EAST TO WEST. SIMILAR PRECIPITATION IS ALONG THE NORTHEASTERN COAST AND SOUTHWESTERN COASTAL WATERS OF NICARAGUA...AND IN THE EASTERN SECTIONS OF HONDURAS. ISOLATED MODERATE CONVECTIVE PRECIPITATION AND REMNANT DEBRIS CLOUDS ARE ELSEWHERE TO THE NORTH OF 15N TO THE WEST OF 80W... AND TO THE SOUTH OF 26N82W 24N87W 22N89W IN THE GULF OF MEXICO. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH THE COASTAL SENEGAL NEAR 14N16W...TO 11N30W 8N37W AND 6N40W. THE ITCZ CONTINUES FROM 6N40W TO 3N44W AND 2N48W. CONVECTIVE PRECIPITATION...ISOLATED MODERATE ELSEWHERE TO THE SOUTH OF 10N BETWEEN 29W AND 60W. A MIDDLE LEVEL TO UPPER LEVEL ATLANTIC OCEAN INVERTED TROUGH IS ALONG 22N58W 15N59W...BEYOND 7N59W IN NORTHERN GUYANA. ...DISCUSSION... THE GULF OF MEXICO... A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS ALONG THE U.S.A. EAST COAST/IN THE COASTAL WATERS OF THE U.S.A. EAST COAST. THE TROUGH PASSES THROUGH SOUTHERN GEORGIA AND THE FLORIDA PANHANDLE INTO THE NORTHEASTERN GULF OF MEXICO NEAR 29N87W...TO A 25N89W CYCLONIC CIRCULATION CENTER...TO THE NORTHWESTERN CORNER OF THE YUCATAN PENINSULA. ISOLATED MODERATE CONVECTIVE PRECIPITATION IS ELSEWHERE TO THE NORTH OF 21N. UPPER LEVEL ANTICYCLONIC WIND FLOW THAT IS ON TOP OF MEXICO IS PUSHING HIGH LEVEL MOISTURE INTO TEXAS TO THE SOUTH OF 32N ALONG 101W. THE ANTICYCLONIC WIND FLOW IS TO THE SOUTHWEST OF 32N101W 25N96W 19N93W. BROAD SURFACE ANTICYCLONIC WIND FLOW COVERS THE AREA. THE SURFACE PRESSURE GRADIENT IS COMPARATIVELY WEAK IN THE GULF OF MEXICO. FROM THE ATLANTIC OCEAN INTO THE NORTH CENTRAL CARIBBEAN SEA... A MIDDLE LEVEL TO UPPER LEVEL TROUGH/SHEAR AXIS EXTENDS FROM A 33N62W CYCLONIC CIRCULATION CENTER TO 24N62W...20N62W... CROSSING PUERTO RICO AND HISPANIOLA...TO A WEAKENING UPPER LEVEL CYCLONIC CIRCULATION CENTER THAT IS NEAR 19N76W BETWEEN JAMAICA AND HAITI. RAINSHOWERS ARE POSSIBLE WITHIN 60 TO 90 NM ON EITHER SIDE OF THE TROUGH/SHEAR AXIS...AND IN THE WATERS THAT ARE BETWEEN HAITI...CUBA...AND JAMAICA. THE REST OF THE CARIBBEAN SEA... ISOLATED MODERATE CONVECTIVE PRECIPITATION IS TO THE NORTH OF 16N BETWEEN 60W AND 68W...MOVING WESTWARD. THE UPPER LEVEL INVERTED TROUGH THAT WAS IN THE SOUTHWESTERN CORNER OF THE AREA FOR THE LAST FEW DAYS HAS MOVED WESTWARD...AND NOW IT MOSTLY IS IN THE EASTERN PACIFIC OCEAN. SCATTERED TO NUMEROUS STRONG CONVECTIVE PRECIPITATION HAS BEEN SPREADING ACROSS EL SALVADOR FROM EAST TO WEST. THE MONSOON TROUGH IS ALONG 9N BETWEEN COLOMBIA ALONG 75W BEYOND 84W IN COSTA RICA. ISOLATED MODERATE CONVECTIVE PRECIPITATION IS TO THE SOUTH OF 13N TO THE WEST OF 75W...ACROSS PARTS OF COSTA RICA AND PANAMA...AND IN THE EASTERN PACIFIC OCEAN COASTAL WATERS OF COLOMBIA TO THE SOUTH OF 6N TO THE EAST OF 82W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT THE 20 TO 25 KNOT WINDS AND 8 TO 9 FOOT SEA HEIGHTS THAT ACCOMPANY THE TROPICAL WAVE/REMNANTS OF T.D. SEVEN THAT ARE ALONG 86W. THE REST OF THE ATLANTIC OCEAN... A MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH IS ALONG 22N57W 16N58W...BEYOND 7N59W IN NORTHERN GUYANA. UPPER LEVEL ANTICYCLONIC WIND FLOW IS ON TOP OF THE AREA OF THE 29N53W 20N58W SURFACE TROUGH. A SURFACE RIDGE EXTENDS FROM A 1023 MB HIGH PRESSURE CENTER THAT IS NEAR 33N25W TO A 1024 MB HIGH PRESSURE CENTER THAT IS NEAR 32N44W...TO BERMUDA...SOUTHWESTWARD PASSING ON TOP OF THE NORTHERN BAHAMAS TO 26N80W NEAR THE EXTREME SOUTHEASTERN COAST OF FLORIDA. AN UPPER LEVEL TROUGH PASSES THROUGH 32N15W TO 28N18W... BECOMING A SHEAR AXIS FROM 28N18W TO 23N26W AND 22N35W. THE TROUGH SUPPORTS A COLD FRONT THAT PASSES THROUGH 32N16W 31N22W. BROKEN MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE WITHIN 30 TO 60 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH 32N18W TO 30N25W TO 32N34W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR DETAILS ABOUT THE 20 TO 25 KNOT WINDS AND 8 FOOT SEA HEIGHTS THAT ARE RELATED TO THE CENTRAL ATLANTIC OCEAN 30N54W 21N58W SURFACE TROUGH. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT