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| #378379 (Received by flhurricane at: 4:47 AM 24.Sep.2010) TCDAT4 TROPICAL STORM LISA DISCUSSION NUMBER 14 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL142010 500 AM AST FRI SEP 24 2010 INFRARED SATELLITE IMAGES SHOW THAT DEEP CONVECTION HAS RE-DEVELOPED AROUND THE LOW-LEVEL CENTER OF LISA IN RECENT HOURS AS CONVECTION IN A BAND WELL NORTHEAST OF THE CENTER HAS GENERALLY BEEN DECREASING. DESPITE THE INCREASE IN CENTRAL CONVECTION...THE OVERALL CLOUD PATTERN OF THE CYCLONE HAS NOT CHANGED MUCH IN ORGANIZATION. DVORAK CI NUMBERS REMAIN UNCHANGED AT 2.0 AND 2.5 FROM SAB AND TAFB...RESPECTIVELY...AND ARE THE BASIS FOR KEEPING THE INITIAL INTENSITY AT 35 KT. THE POSSIBILITY OF LISA INTENSIFYING IS DECREASING. IN LESS THAN 24 HOURS...LISA IS EXPECTED TO REACH AN ENVIRONMENT OF INCREASING SOUTHWESTERLY VERTICAL WIND SHEAR... COOLER WATERS...AND HIGHER STABILITY. THESE FACTORS SHOULD PROMOTE A STEADY WEAKENING...PERHAPS MORE RAPID THAN CURRENTLY FORECAST. THE NHC INTENSITY FORECAST IS ABOUT THE SAME AS THE PREVIOUS ONE BUT REMAINS A BIT LOWER THAN MOST OF THE STATISTICAL-DYNAMICAL GUIDANCE. AN 0349 UTC AMSR-E MICROWAVE OVERPASS WAS HELPFUL IN DETERMINING THE CENTER OF LISA. THE CYCLONE APPEARS TO BE DRIFTING NORTHEASTWARD... AND THE INITIAL MOTION ESTIMATE IS 035/04. GLOBAL MODELS SHOW LISA MOVING GENERALLY NORTHWARD WITH SOME INCREASE IN FORWARD SPEED DURING THE NEXT COUPLE OF DAYS...STEERED AROUND THE WESTERN PERIPHERY OF A LOW- TO MID-LEVEL RIDGE OVER NORTHWEST AFRICA. AFTER THAT...A WEAKER LISA OR ITS REMNANTS SHOULD MOVE NORTH- NORTHWESTWARD IN THE LOW-LEVEL FLOW AND EVENTUALLY DISSIPATE. THE NEW NHC TRACK FORECAST IS ADJUSTED A BIT TO THE RIGHT BUT NOT AS FAR EAST AS THE GFDL/HWRF/UKMET WHICH GENERALLY HAVE STRONGER AND LIKELY UNREALISTIC REPRESENTATIONS OF LISA...ESPECIALLY BEYOND 48 HOURS. THE NHC TRACK IS LEFT OF THE DYNAMICAL MODEL CONSENSUS AND ROUGHLY IN THE MIDDLE OF THE GUIDANCE ENVELOPE. FORECAST POSITIONS AND MAX WINDS INITIAL 24/0900Z 18.4N 27.7W 35 KT 12HR VT 24/1800Z 19.2N 27.9W 40 KT 24HR VT 25/0600Z 20.6N 28.3W 35 KT 36HR VT 25/1800Z 22.1N 28.8W 30 KT 48HR VT 26/0600Z 23.6N 29.2W 30 KT 72HR VT 27/0600Z 26.0N 30.5W 25 KT...POST-TROP/REMNT LOW 96HR VT 28/0600Z 27.5N 32.0W 20 KT...POST-TROP/REMNT LOW 120HR VT 29/0600Z...DISSIPATED $$ FORECASTER KIMBERLAIN |
