000 AXNT20 KNHC 281156 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE AUG 28 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 FEATURES... THE CENTER OF TROPICAL STORM ISAAC AT 28/1200 UTC IS NEAR 27.8N 88.2W. THIS POSITION IS ABOUT 105 MILES TO THE SOUTH-SOUTHEAST OF THE MOUTH OF THE MISSISSIPPI RIVER...AND ABOUT 185 MILES TO THE SOUTH-SOUTHEAST OF BILOXI MISSISSIPPI. ISAAC IS MOVING NORTHWESTWARD AT AROUND 5 KNOTS. THE MINIMUM CENTRAL PRESSURE IS 976 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 60 KT WITH GUSTS TO 75 KT. PLEASE READ THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND THE PUBLIC ADVISORY... MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. CONVECTIVE PRECIPITATION ...NUMEROUS STRONG IS FROM 25N TO 28N BETWEEN 87W AND 91W. CONVECTIVE DEBRIS CLOUDS WITH POSSIBLE RAINSHOWERS ARE IN THE WATERS FROM CUBA TO 32N BETWEEN 76W AND 80W...IN AN AREA OF MIDDLE LEVEL TO UPPER LEVEL DIFFLUENT WIND FLOW. BROKEN TO OVERCAST MULTILAYERED CLOUDS COVER THE AREA FROM 19N IN THE YUCATAN PENINSULA OF MEXICO TO 33N BETWEEN SOUTH CAROLINA AND ALABAMA...INTO MISSISSIPPI...AND THE SOUTHEASTERN HALF OF LOUISIANA. ALL RESIDENTS FROM FLORIDA TO LOUISIANA SHOULD STAY TUNED TO ALL BULLETINS THAT ARE ISSUED BY THE NATIONAL HURRICANE CENTER AND THE LOCAL NATIONAL WEATHER SERVICE OFFICES FOR UPDATES ABOUT T.S. ISAAC. AN ATLANTIC OCEAN 1012 MB LOW PRESSURE CENTER IS NEAR 22N43W. NUMEROUS STRONG CONVECTIVE PRECIPITATION IS FROM 22N TO 25N BETWEEN 40W AND 43W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE PRECIPITATION ARE WITHIN 120 TO 210 NM ON EITHER SIDE OF 29N27W 28N35W 25N40W 20N46W. MIDDLE LEVEL NORTHEASTERLY WIND FLOW IS WITHIN 360 NM TO THE WEST OF MASS OF CONVECTIVE PRECIPITATION. UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN TO THE NORTH OF 20N BETWEEN 20W AND 40W. ENVIRONMENTAL CONDITIONS ARE ONLY MARGINALLY CONDUCIVE FOR DEVELOPMENT DURING THE NEXT COUPLE OF DAYS. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS THE LOW MOVES WEST-NORTHWESTWARD TO NORTHWESTWARD AT 9 TO 13 KNOTS. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 23N23W...ACROSS THE WESTERN CAPE VERDE ISLANDS NEAR 17N25W...TO A 1011 MB LOW PRESSURE CENTER THAT IS NEAR 12N25W. SCATTERED STRONG CONVECTIVE PRECIPITATION IS FROM 12N TO 15N BETWEEN 21W AND 29W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH IS INDISTINCT AS IT HAS BEEN DISRUPTED BY THE LARGE-SCALE WIND FLOW THAT IS MOVING AROUND THE 23N23W 12N25W TROPICAL WAVE...AND THE WIND FLOW THAT IS MOVING AROUND THE 1012 MB LOW PRESSURE CENTER THAT IS NEAR 22N43W. THE MONSOON TROUGH EVENTUALLY IS ALONG 14N42W 10N50W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 6N TO 11N BETWEEN AFRICA AND 20W...ELSEWHERE FROM 8N TO 13N BETWEEN 24W AND 35W...ISOLATED MODERATE WITHIN A 30 NM RADIUS 2N37W AND WEAKENING WITHIN A 30 NM RADIUS OF 10N45.5W...SCATTERED MODERATE TO STRONG FROM 12N TO 14N BETWEEN 55W AND 60W NEAR BARBADOS. ...DISCUSSION... THE GULF OF MEXICO... TROPICAL STORM ISAAC IS MOVING THROUGH THE EASTERN HALF OF THE AREA. PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR DETAILS ABOUT THIS CYCLONE. THE NORTHERN YUCATAN PENINSULA MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER OF 24 HOURS AGO HAS BECOME CAUGHT UP IN AN ELONGATED NORTHWEST-TO-SOUTHEAST ORIENTED TROUGH. A CYCLONIC CIRCULATION CENTER WAS NEAR 24N94W ABOUT SIX HOURS AGO. THAT SAME CYCLONIC CIRCULATION IS NOW NEARLY DISSIPATED NEAR 24N96W. THE LARGE-SCALE DEEP LAYER WIND FLOW OF ISAAC DOMINATES AND PRACTICALLY HAS OVERRUN THE ELONGATED TROUGH COMPLETELY. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION ACCOMPANIES THE TROUGH. THE SURFACE PRESSURE PATTERN IN THE EASTERN GULF OF MEXICO IS MADE UP OF THE CLOSED ISOBARS THAT SURROUND ISAAC. THESE ISOBARS COVER THE AREA TO THE EAST OF 95W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE OFFSHORE FORECAST...MIAOFFNT4...FOR MORE DETAILS ABOUT TROPICAL STORM ISAAC. FROM THE ATLANTIC OCEAN...INTO THE CARIBBEAN SEA... A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS ALONG 25N72W...TO A CYCLONIC CIRCULATION CENTER THAT IS NEAR 19N73W IN WESTERN HAITI...ACROSS THE CARIBBEAN SEA...TO THE COLOMBIA COAST NEAR 10N76W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION IS IN THE DOMINICAN REPUBLIC TO THE EAST OF 70W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS COVER THE AREAS TO THE SOUTH OF 24N BETWEEN 66W AND 80W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION HAS BEEN OCCURRING IN AN AREA OF UPPER LEVEL DIFFLUENT WIND FLOW IN THE CARIBBEAN SEA BETWEEN 80W AND 85W...MOVING FROM CUBA INTO EASTERN HONDURAS AND NORTHEASTERN AND EASTERN NICARAGUA...AND TO THE COASTAL WATERS AND POSSIBLY THE COASTAL PLAINS OF COSTA RICA AND PANAMA. THE REST OF THE CARIBBEAN SEA... THE MONSOON TROUGH IS ALONG 9N73W IN COLOMBIA...THROUGH 9N80W IN PANAMA...BEYOND NORTHWESTERN COSTA RICA. IT IS POSSIBLE THAT THE SCATTERED STRONG CONVECTIVE PRECIPITATION...THAT IS IN THE EASTERN PACIFIC OCEAN TO THE NORTH OF 6N BETWEEN 81W AND 85W TO THE SOUTH OF PANAMA AND COSTA RICA...IS RELATED TO THE MONSOON TROUGH. BROAD UPPER LEVEL CYCLONIC WIND FLOW COVERS THE NORTHWESTERN CORNER OF THE AREA...RESPONDING TO THE INFLUENCE OF THE WIND FLOW THAT IS MOVING AROUND TROPICAL STORM ISAAC. 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 11 FOOT SEA HEIGHTS DURING THE 48 HOUR FORECAST PERIOD FROM 12N TO 18N BETWEEN 65W AND 79W. THE REST OF THE ATLANTIC OCEAN... BROAD MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN TO THE SOUTH OF 30N BETWEEN 20W AND 60W. COMPARATIVELY DRIER AIR IN SUBSIDENCE COVERS THE AREA...EXCEPT FOR THE CONVECTIVE PRECIPITATION THAT ACCOMPANIES THE 1012 MB LOW PRESSURE CENTER THAT IS NEAR 22N43W...AND THAT WHICH IS RELATED TO THE MONSOON TROUGH/THE ITCZ NEAR BARBADOS. A SURFACE RIDGE EXTENDS FROM A 1022 MB HIGH PRESSURE CENTER THAT IS NEAR 31N23W...TO A 1021 MB HIGH PRESSURE CENTER THAT IS NEAR 32N54W...TO 24N61W...INTO THE CARIBBEAN SEA TO JAMAICA. PLEASE READ THE HIGH SEAS FORECASTS...MIAHSFAT2...FOR DETAILS ABOUT 20 TO 25 KNOT WINDS AND 8 FOOT SEA HEIGHTS TO THE SOUTH OF 26N TO THE WEST OF 78W FOR THE NEXT SIX HOURS. A SECOND FEATURE OF INTEREST IS A 1011 MB LOW PRESSURE CENTER THAT STARTS NEAR 22N43W...IS A POSSIBLE TROPICAL CYCLONE NEAR 23N45W IN 24 HOURS...AND A POSSIBLE TROPICAL CYCLONE NEAR 24N49W IN 48 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT