000 AXNT20 KNHC 280605 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM ISAAC AT 28/0600 UTC IS NEAR 27.4N 87.7W. THIS POSITION IS ABOUT 126 NM TO THE SOUTHEAST OF THE MOUTH OF THE MISSISSIPPI RIVER...AND ABOUT 191 NM TO THE SOUTH-SOUTHEAST OF BILOXI MISSISSIPPI. ISAAC IS MOVING NORTHWESTWARD 10 KNOTS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 978 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 86W AND 91W. CONVECTIVE PRECIPITATION HAS BEEN IN THE WATERS FROM CUBA TO 32N BETWEEN 77W AND 80W...IN AN AREA OF MIDDLE LEVEL TO UPPER LEVEL DIFFLUENT WIND FLOW. MUCH OF THAT PRECIPITATION HAS BEEN WEAKENING WITH TIME AS THE CLOUD TOP TEMPERATURES HAVE BEEN WARMING. 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 21N42W. NUMEROUS STRONG CONVECTIVE PRECIPITATION IS FROM 23N TO 25N BETWEEN 40W AND 42W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE PRECIPITATION ARE WITHIN 120 TO 210 NM ON EITHER SIDE OF 29N29W 27N36W 24N40W 20N45W. 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 9 TO 13 KNOTS. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 22N21W...ACROSS THE CAPE VERDE ISLANDS...TO A 1012 MB LOW PRESSURE CENTER THAT IS NEAR 12N23W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION IS FROM 12N TO 16N BETWEEN 22W AND 27W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL MAURITANIA NEAR 17N16W TO 13N20W...TO A 1012 MB LOW PRESSURE CENTER THAT IS NEAR 12N23W. THE MONSOON TROUGH IS DISRUPTED BY THE LARGE-SCALE WIND FLOW THAT IS MOVING AROUND THE 1012 MB LOW PRESSURE CENTER THAT IS NEAR 21N42W. THE MONSOON TROUGH STARTS AGAIN NEAR 14N43W AND IT CONTINUES TO 11N51W. THE ITCZ CONTINUES FROM 11N51W TO 9N60W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 7N TO 10N BETWEEN AFRICA AND 19W...FROM 13N TO 15N BETWEEN AFRICA AND 18W...FROM 12N TO 16N BETWEEN 22W AND 27W...AND FROM 9N TO 12N BETWEEN 25W AND 33W. ISOLATED MODERATE TO LOCALLY STRONG CONVECTIVE PRECIPITATION IS FROM 1N TO 3N BETWEEN 35W AND 39W...FROM 9N TO 11N BETWEEN 43W AND 47W...AND FROM 11N TO 14N BETWEEN 53W AND 60W. ...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 EVENTUALLY BECAME CAUGHT UP IN AN ELONGATED NORTHWEST-TO-SOUTHEAST ORIENTED TROUGH. A CYCLONIC CIRCULATION CENTER NOW IS NEAR 24N94W. THE LARGE-SCALE DEEP LAYER WIND FLOW OF ISAAC DOMINATES AND NEARLY IS OVERRUNNING THE ELONGATED TROUGH. 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. THE RESULTING SURFACE PRESSURE PATTERN THAT IS IN THE WESTERN HALF OF THE AREA IS WEAK AT THE MOMENT. 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 27N68W IN THE ATLANTIC OCEAN...TO A 23N72W CYCLONIC CIRCULATION CENTER... CROSSING HISPANIOLA INTO THE CARIBBEAN SEA...TO A 17N72W CYCLONIC CIRCULATION CENTER...TO THE COLOMBIA COAST NEAR 11N75W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE PRECIPITATION COVER THE AREAS TO THE SOUTH OF 24N BETWEEN 64W AND 78W. NUMEROUS STRONG CONVECTIVE PRECIPITATION...THAT WAS DEVELOPING IN VENEZUELA BETWEEN 80W AND LAKE MARACAIBO STARTING AT 27/2145 UTC...HAS BEEN DISSIPATING DURING THE LAST FEW HOURS. CONVECTIVE DEBRIS CLOUDS REMAIN FROM LAKE MARACAIBO NEAR 9N TO 13N IN THE VENEZUELA COASTAL WATERS BETWEEN 67W AND 72W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION HAS BEEN OCCURRING IN AN AREA OF UPPER LEVEL DIFFLUENT WIND FLOW IN THE CARIBBEAN SEA BETWEEN 77W AND THE COASTAL WATERS OF CENTRAL AMERICA ALONG 83W. THE REST OF THE CARIBBEAN SEA... THE MONSOON TROUGH IS ALONG 8N73W 7N76W IN COLOMBIA...THROUGH 8N81W IN PANAMA...BEYOND NORTHWESTERN COSTA RICA. IT IS POSSIBLE THAT THE SCATTERED MODERATE TO STRONG CONVECTIVE PRECIPITATION THAT IS TO THE SOUTH OF 11.5N BETWEEN 79W AND 82W TO THE NORTH OF PANAMA IS MORE RELATED TO THE UPPER LEVEL DIFFLUENT WIND FLOW THAN 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 11N TO 17N BETWEEN 65W AND 80W. 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 21N42W...AND THAT WHICH IS RELATED TO THE MONSOON TROUGH/THE ITCZ. A SURFACE RIDGE PASSES OVER THE MADEIRA ISLANDS TO 30N30W TO A 1023 MB HIGH PRESSURE CENTER THAT IS NEAR 32N54W...TO A 1021 MB HIGH PRESSURE CENTER THAT IS NEAR 34N67W. ANOTHER RIDGE EXTENDS FROM THE 32N54W HIGH PRESSURE CENTER TO 21N62W AND 12N63W IN THE CARIBBEAN SEA. PLEASE READ THE HIGH SEAS FORECASTS...MIAHSFAT2...FOR DETAILS ABOUT 20 TO 25 KNOT WINDS AND 9 FOOT SEA HEIGHTS TO THE WEST OF 78W FOR THE NEXT 12 HOURS. A SECOND FEATURE OF INTEREST IS A 1012 MB LOW PRESSURE CENTER THAT STARTS NEAR 21N42W... IS NEAR 22N45W IN 24 HOURS...AND NEAR 23N50W IN 48 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT