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| #10844 (Received by flhurricane at: 10:39 PM 28.Sep.2004) TCDAT3 TROPICAL STORM LISA DISCUSSION NUMBER 39 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT TUE SEP 28 2004 VARIOUS SATELLITE SOURCES INDICATE LISA HAS BECOME A LITTLE BETTER ORGANIZED AND HAS STRENGTHENED. A 28/1936Z TRMM OVERPASS INDCIATED A NICE MID-LEVEL EYE FEATURE THAT WAS STILL SHEARED ABOUT 30 NMI TO THE NORTHEAST OF THE LOW-LEVEL CENTER. A 28/2115Z HI-RES QUIKSCAT OVERPASS REVEALED A SEVERAL RAINFLAGGED WINDS OF 60-70 KT AND A 28/1708Z CIRA/AMSU OVERPASS PROVIDED A PRESSURE OF 991 MB AND SURFACE WIND ESTIMATE OF 59 KT. THE INITIAL INTENSITY OF 55 KT IS BASED ON A COMBINATION OF THE MICROWAVE DATA AND A DVORAK SATELLITE ESTIMATE OF T3.5...OR 55 KT FROM TAFB. THE INITIAL MOTION ESTIMATE IS 360/11. LISA IS EXPECTED TO MOVE NORTH TO NORTHWESTWARD FOR THE NEXT 36 HOURS OR SO AROUND THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE LOCATED ALONG 30-32N LATITUDE. BY 48-72 HOURS...AN APPROACHING MID-LEVEL SHORTWAVE TROUGH IS EXPECTED TO TURN LISA MORE NORTHEASTWARD AND BRING ABOUT RECURVATURE AROUND THE NORTH SIDE OF THE RIDGE. IN 96-120 HOURS... LISA IS EXPECTED TO BE CAPTURED BY THE SHORTWAVE TROUGH AND BECOME EXTRATROPICAL...OR EVEN MERGE WITH ANOTHER EXTRATROPICAL LOW. THE NHC MODEL GUIDANCE IS IN GOOD AGREEMENT ON THIS EVOLVING SCENARIO. LISA REMAINS A RATHER TENACIOUS TROPICAL CYCLONE BY DEVELOPING A NICE MID-LEVEL EYE FEATURE DESPITE RATHER STRONG VERTICAL SHEAR. THE VERTICAL SHEAR ACROSS LISA HAS BEEN SLOWLY DECREASING AND THE SHIPS MODEL IS FORECASTING THE SHEAR TO DECREASE TO LESS THAN 5 KT IN THE 24-72 HOUR PERIOD. LISA IS EXPECTED TO REMAIN OVER 26C OR HIGHER SSTS THROUGH 36 HOURS...SO SOME SLOW STRENGTHENING IS FORECAST. AFTER 36 HOURS...LISA IS EXPECTED TO MOVE OVER SUB-25C SSTS AND SLOW WEAKENING IS FORECAST TO OCCUR. THE OFFICIAL INTENSITY FORECAST IS SLIGHTLY LOWER THAN THE SHIPS MODEL FORECAST. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 29/0300Z 27.0N 46.5W 55 KT 12HR VT 29/1200Z 28.7N 46.7W 55 KT 24HR VT 30/0000Z 30.5N 47.3W 60 KT 36HR VT 30/1200Z 32.3N 48.2W 65 KT 48HR VT 01/0000Z 34.0N 48.7W 60 KT 72HR VT 02/0000Z 38.0N 47.0W 60 KT 96HR VT 03/0000Z 41.0N 42.0W 55 KT...BECOMING EXTRATROPICAL 120HR VT 04/0000Z 43.5N 32.0W 50 KT...EXTRATROPICAL |
