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#378831 (Received by flhurricane at: 4:47 AM 26.Sep.2010) TCDAT4 TROPICAL DEPRESSION LISA DISCUSSION NUMBER 23 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL142010 500 AM AST SUN SEP 26 2010 STRONG SOUTHWESTERLY SHEAR CONTINUES TO TAKE A TOLL ON LISA AS THE CENTER OF THE CYCLONE IS EXPOSED TO THE SOUTHWEST OF A SMALL AREA OF REMAINING THUNDERSTORM ACTIVITY. THE INITIAL INTENSITY IS LOWERED TO 30 KT...BASED ON A BLEND OF DVORAK SATELLITE ESTIMATES AND AN EARLIER ASCAT PASS. THE SHEAR...ALONG WITH DRY AIR AND COOL SSTS...SHOULD CAUSE CONTINUED WEAKENING...AND LISA IS FORECAST TO DEGENERATE TO A REMNANT LOW IN 12-24 HOURS. THE INITIAL MOTION ESTIMATE IS 345/8. A NORTH-NORTHWESTWARD MOTION IS EXPECTED DURING THE NEXT FEW DAYS AS THE CYCLONE MOVES BETWEEN A TROUGH OVER THE EASTERN ATLANTIC AND A RIDGE NEAR NORTHWESTERN AFRICA. THE GUIDANCE HAS GENERALLY SHIFTED WESTWARD THIS CYCLE... AND THE OFFICIAL FORECAST HAS BEEN ADJUSTED IN THAT DIRECTION. LATE IN THE FORECAST PERIOD...A SURFACE HIGH IS EXPECTED TO BUILD NORTHWEST OF THE AZORES WHICH WILL LIKELY CAUSE THE REMNANT LOW TO SLOW DOWN AND TURN NORTHWESTWARD BEFORE IT DISSIPATES. FORECAST POSITIONS AND MAX WINDS INITIAL 26/0900Z 25.1N 29.0W 30 KT 12HR VT 26/1800Z 26.0N 29.5W 25 KT 24HR VT 27/0600Z 27.2N 30.2W 25 KT...POST-TROP/REMNT LOW 36HR VT 27/1800Z 28.5N 30.9W 25 KT...POST-TROP/REMNT LOW 48HR VT 28/0600Z 29.8N 31.3W 25 KT...POST-TROP/REMNT LOW 72HR VT 29/0600Z 31.5N 31.3W 25 KT...POST-TROP/REMNT LOW 96HR VT 30/0600Z 32.0N 31.5W 20 KT...POST-TROP/REMNT LOW 120HR VT 01/0600Z...DISSIPATED $$ FORECASTER BROWN |