000 AXNT20 KNHC 031800 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED SEP 03 2008 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION GUSTAV IS DRIFTING NORTH-NORTHEAST WITH HEAVY RAIN CONTINUING OVER THE LOWER MISSISSIPPI VALLEY. AT 3/1500Z...ITS CENTER IS LOCATED NEAR 33.8N 94.3W OR ABOUT 30 MILES...50 KM...NORTHWEST OF TEXARKANA ARKANSAS AND ABOUT 105 MILES...170 KM...SOUTH OF FORT SMITH ARKANSAS MOVING N-NE AT NEAR 2 KT...5 KM/HR. THIS MOTION WILL CONTINUE WITH A GRADUAL TURN TOWARD THE NORTHEAST AND AN INCREASE IN FORWARD SPEED TODAY AND THURSDAY. MAXIMUM SUSTAINED WINDS ARE 22 KT WITH HIGHER GUSTS. THE MINIMUM CENTRAL PRESSURE IS 997 MB. FLASH FLOOD WARNINGS ARE IN EFFECT FOR A LARGE PART OF CENTRAL AND NORTHEASTERN LOUISIANA...WESTERN MISSISSIPPI...SOUTHEASTERN ARKANSAS...PORTIONS OF EASTERN OKLAHOMA AND NORTHWESTERN ARKANSAS. STORM TOTAL RAINFALL AMOUNTS UP TO 16 INCHES HAVE BEEN REPORTED IN PARTS OF LOUISIANA. SATELLITE PICTURES AND DOPPLER RADAR CONTINUE TO SHOW THE CIRCULATION OF GUSTAV WITH A NARROW OUTER RAINBAND OVER THE NW CORNER OF THE GULF. AT 03/1800 TROPICAL STORM HANNA IS CENTERED NEAR 21.4N 72.0W WEST OR JUST SOUTH OF THE CAICOS ISLANDS. HANNA IS MOVING TOWARD THE N-NW AT 9 KT. A TURN TO THE NORTHWEST WITH AN INCREASE IN FORWARD SPEED IS EXPECTED OVER THE NEXT 24 HOURS. ON THE FORECAST TRACK...THE CENTER OF HANNA SHOULD BE MOVING THROUGH OR JUST EAST OF THE CENTRAL AND NORTHWESTERN BAHAMAS OVER THE NEXT COUPLE OF DAYS. ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. LITTLE CHANGE IN STRENGTH IS FORECAST TODAY...BUT HANNA COULD REGAIN HURRICANE STRENGTH TOMORROW OR ON FRIDAY. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. HANNA IS EXPECTED TO PRODUCE RAINFALL TOTALS OF 4 TO 8 INCHES...WITH MAXIMUM ISOLATED AMOUNTS OF 12 INCHES...OVER THE SOUTHEASTERN BAHAMAS...THE TURKS AND CAICOS ISLANDS...AND EASTERN CUBA. RAINFALL TOTALS OF 6 TO 10 INCHES...WITH ISOLATED MAXIMUM AMOUNTS OF UP TO 15 INCHES...ARE POSSIBLE OVER HISPANIOLA...WHERE THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. MODERATE TO LOCALLY HEAVY RAINFALL IS POSSIBLE ALONG THE EAST COAST OF FLORIDA BY FRIDAY MORNING. TROPICAL STORM IKE IS ALMOST A HURRICANE. AT 3/1500 UTC... ITS CENTER IS NEAR 20.8N 51.2W OR ABOUT 645 NM EAST-NORTHEAST OF THE LEEWARD ISLANDS MOVING W-NW AT 16 KT. THIS GENERAL MOTION IS EXPECTED TO CONTINUE THROUGH THURSDAY...FOLLOWED BY A TURN TO THE WEST ON FRIDAY...TAKING IKE OVER THE OPEN WATERS OF THE WEST-CENTRAL ATLANTIC DURING THE NEXT COUPLE OF DAYS. IT IS TOO EARLY TO DETERMINE WHAT IF ANY LAND AREAS MIGHT BE DIRECTLY AFFECTED BY IKE. ESTIMATED MINIMUM CENTRAL PRESSURE IS 991 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. STRENGTHENING IS FORECAST DURING THE NEXT DAY OR TWO...AND IKE IS FORECAST TO BECOME A HURRICANE LATER TODAY. STEADY STRENGTHENING IS FORECAST AT DAYS 3-5...AND IKE COULD REACH MAJOR HURRICANE STATUS BEFORE FIVE DAYS PASS. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. IKE IS WRAPPING UP SOME SOLID CONVECTIVE BANDING AS VIEWED IN VISIBLE IMAGERY. IT IS MOVING ALONG THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL RIDGE OVER THE CENTRAL ATLANTIC. TROPICAL STORM JOSEPHINE IS CENTERED NEAR 13.8N 28.8W AT 03/1500 UTC OR ABOUT 265 NM...485 KM...W-SW OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING W AT 9 KT. A TURN TOWARD THE WEST-NORTHWEST WITH AN INCREASE IN FORWARD SPEED IS EXPECTED DURING THE NEXT COUPLE OF DAYS. ESTIMATED MINIMUM CENTRAL PRESSURE IS 994 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. LITTLE CHANGE IN STRENGTH IS FORECAST THROUGH THURSDAY...BUT A WEAKENING TREND IS FORECAST TO BEGIN ON FRIDAY. WATER VAPOR IMAGERY SHOWS UPPER-LEVEL WESTERLY FLOW...ASSOCIATED WITH A TROUGH TO THE WEST...IS BEGINNING TO AFFECT JOSEPHINE. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. CONVECTION HAS SLIGHTLY DIMINISHED OVER THE PAST FEW HOURS...AND JOSEPHINE NOW LOOKS LESS ORGANIZED THAN THIS MORNING. ...TROPICAL WAVES... THE TROPICAL WAVE THAT WAS ALONG 62W ON THE 0600 UTC SURFACE MAP IS NO LONGER DISCERNIBLE. IT WAS ABSORBED BY THE LARGE CIRCULATION OF T.S. HANNA. A NEW TROPICAL WAVE IS JUST MOVING OFF THE AFRICAN COAST. THE VERTICAL SOUNDING FROM DAKAR IS STILL SHOWING NE WINDS AT LOW LEVELS. AN EARLIER QSCAT PASS INDICATED A CYCLONIC CIRCULATION NEAR 11N16W. WILL WAIT FOR MORE DATA BEFORE PLACING THE WAVE ON THE SURFACE MAP. ...THE ITCZ... THE ITCZ AXIS IS PRETTY WEAK TODAY. IT IS ANALYZED ALONG 7N12W 10N25W 10N32W 8N45W 10N60W. ONLY ISOLATED MODERATE CONVECTION IS SEEN ALONG THE AXIS. MOST THE MODERATE TO STRONG CONVECTION IS RELATED TO THE TROPICAL CYCLONES MENTIONED ABOVE. ...DISCUSSION... GULF OF MEXICO... A WEAK SURFACE RIDGE IS POSITIONED ACROSS THE GULF OF MEXICO IN THE WAKE OF T.D. GUSTAV THAT IS INLAND OVER THE LOWER MISSISSIPPI VALLEY. AN AREA OF SHOWERS WITH ISOLATED TSTMS HAS DEVELOPED OVER THE BAY OF CAMPECHE LIKELY ASSOCIATED WITH A 1007 MB SFC LOW THAT IS LOCATED NEAR 19N94W AND A DIFFLUENT PATTERN ALOFT. AN UPPER-LEVEL HIGH CENTERED OVER THE BAY OF CAMPECHE IS ENHANCING THIS CONVECTIVE ACTIVITY. THIS HIGH EXTENDS A RIDGE NE OVER MOST OF THE GULF...THE SE CONUS...FLORIDA...WEST-CENTRAL CUBA...THE NW CARIBBEAN AND MOST OF CENTRAL AMERICA. MODERATE TO STRONG SUBSIDENCE/DRY AIR IS NOTED OVER THE WESTERN GULF N OF 23N W OF 90W. CARIBBEAN SEA... THE MAIN WEATHER MAKER ACROSS THE BASIN IS T.S. HANNA. AREAS OF HEAVY RAINFALL...GUSTY WINDS AND LOCALIZED FLOODING...ASSOCIATED WITH THE OUTER RAINBANDS OF THIS TROPICAL CYCLONE HAVE BEEN AFFECTING LARGE SECTIONS OF PUERTO RICO AND THE US/UK VIRGIN ISLANDS AS WELL AS PARTS OF DOMINICAN REPUBLIC PARTICULARLY THE SOUTH COAST AND COASTAL WATERS...INCLUDING ALSO THE MONA AND ANEGADA PASSAGES. RAINBANDS ASSOCIATED WITH THE OVERALL CIRCULATION OF HANNA AREA ALSO NOTED OVER THE EAST AND CENTRAL CARIBBEAN. WESTERLY SHEAR AND DRY AIR ASSOCIATED WITH THE UPPER LOW SPINNING OVER THE CENTRAL BAHAMAS CONTINUES TO INHIBIT THE DEVELOPMENT OF HANNA...BUT THESE CONDITIONS SHOULD DIMINISH OVER THE NEXT COUPLE OF DAYS. STRONG UPPER NLY WINDS DOMINATES THE WESTERN CARIBBEAN. STRONG SW WINDS ARE BLOWING ACROSS THE N CENTRAL CARIBBEAN...ESPECIALLY IN THE WINDWARD PASSAGE WHILE UNUSUAL W WINDS ARE OBSERVED WELL S TOWARD THE COAST OF COLOMBIA DUE TO HANNA'S LARGE CIRCULATION. ATLANTIC OCEAN... THREE TROPICAL STORMS ARE LOCATED IN THE DISCUSSION AREA. FROM EAST TO WEST...JOSEPHINE...IKE AND HANNA. THE LAST ONE IS IMPACTING THE SE BAHAMAS. SEE SPECIAL FEATURES ABOVE FOR DETAILS. UPPER RIDGE CENTERED IN THE BAY OF CAMPECHE EXTENDS INTO THE WRN ATLC W OF 78W. AN UPPER-LEVEL LOW OVER THE CENTRAL BAHAMAS HAS A TROUGH EXTENDING SOUTH OVER EASTERN CUBA. A LARGE UPPER LEVEL HIGH CENTERED NEAR 30N48W EXTENDS A RIDGE AXIS INTO THE TROPICAL ATLC REACHING 10N. AN UPPER LEVEL TROUGH EXTENDS SW ACROSS THE ERN ATLC FROM AN UPPER LEVEL LOW NOW LOCATED NEAR 22N31W. LOCATED NORTH OF THE CANARY ISLANDS NEAR 31N17W. UPPER-LEVEL ELY WINDS DOMINATE MOST OF THE DEEP TROPICS W OF 35W. AT THE SURFACE...A 1027 MB HIGH LOCATED NEAR 36N40W EXTENDS A RIDGE OVER PARTS OF THE CENTRAL AND ERN ATLC E OF 48W. THE TAIL END OF A FRONT...AS A SURFACE TROUGH... ENTERS THE AREA NEAR 31N62W THAN CONTINUES SW TO 28N65W. $$ GR