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| #377197 (Received by flhurricane at: 4:53 AM 19.Sep.2010) TCDAT2 TROPICAL STORM JULIA DISCUSSION NUMBER 29 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL122010 500 AM AST SUN SEP 19 2010 SOMEWHAT UNEXPECTEDLY...THE ASCAT PASS AT 0106Z OVER JULIA SHOWED 50 TO 55 KT WINDS AT THE SURFACE...WHICH SUGGESTS THAT THE CYCLONE WAS AT LEAST 55 KT AROUND 0000Z GIVEN THE LOW BIAS OF THAT INSTRUMENT. SINCE THEN...THE CONVECTION HAS WEAKENED AND THE CDO HAS BECOME FRAGMENTED. DVORAK INTENSITY ESTIMATES WERE 3.0...OR 45 KT...FROM TAFB AND 2.5...OR 35 KT...FROM SAB. THE INTENSITY WAS SET AT 50 KT AT THE SYNOPTIC TIME AND IS 45 KT FOR THIS ADVISORY. THE MOTION OF JULIA IS 355 DEGREES AT 14 KT...WHICH IS FAIRLY WELL KNOWN DUE TO AN 0506Z AQUA PASS THAT WAS JUST RECEIVED. THE CYCLONE IS IN THE PROCESS OF RECURVING AROUND THE DEEP LAYER SUBTROPICAL RIDGE TO ITS SOUTHEAST. A MODEST DECELERATION IS EXPECTED OVER THE NEXT 36 HOURS AS JULIA TURNS TOWARD THE NORTHEAST. THE MODEL GUIDANCE HAS SHIFTED SIGNIFICANTLY SOUTHEASTWARD AND THE TRACK FORECAST IS A BLEND OF THE PREVIOUS ADVISORY AND THE FAIRLY CLUSTERED MODEL CONSENSUS. THE MODEST REINTENSIFICATION OF JULIA IS NOT LIKELY TO BE REPEATED. THE CYCLONE WILL BE MOVING OVER SUB-26C SSTS IN ABOUT A DAY WHILE BEING BLUDGEONED BY ABOUT 50 KT UPPER TROPOSPHERIC NORTHWESTERLIES. GRADUAL DECAY IS EXPECTED OVER THE NEXT TWO DAYS...AFTER WHICH JULIA SHOULD BE ABSORBED INTO THE VERY LARGE CIRCULATION OF IGOR. THE INTENSITY FORECAST IS NEARLY IDENTICAL TO THE PREVIOUS ADVISORY...BUT BELOW THE INTENSITY MODEL CONSENSUS WHICH APPEARS TO HOLD ON TO A ROBUST CYCLONE FOR TOO LONG. THE AFOREMENTIONED ASCAT PASS ALLOWED FOR AN ADJUSTMENT TO THE WIND RADII UTILIZED IN THIS ADVISORY. FORECAST POSITIONS AND MAX WINDS INITIAL 19/0900Z 33.6N 51.8W 45 KT 12HR VT 19/1800Z 35.7N 51.2W 40 KT 24HR VT 20/0600Z 36.8N 49.4W 30 KT 36HR VT 20/1800Z 37.7N 47.5W 25 KT...POST-TROP/REMNT LOW 48HR VT 21/0600Z 39.5N 45.5W 25 KT...POST-TROP/REMNT LOW 72HR VT 22/0600Z...DISSIPATED $$ FORECASTER LANDSEA/BRENNAN |
