000 WTNT41 KNHC 300250 TCDAT1 HURRICANE DANIELLE DISCUSSION NUMBER 35 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010 1100 PM AST SUN AUG 29 2010 DEEP CONVECTION HAS GRADUALLY ERODED INTO AN ELONGATED BAND IN THE NORTHERN SEMICIRCLE AS DANIELLE CONTINUES TO MOVE OVER COOLER WATER AND TAKES ON THE APPEARANCE OF AN EXTRATROPICAL CYCLONE. HOWEVER... A UW-CIMSS AMSU INTENSITY ESTIMATE AT 29/2133 UTC STILL INDICATED A STRONG UPPER-LEVEL WARM CORE...AN INTENSITY ESTIMATE OF 87 KT AND A PRESSURE OF 968 MB. THE INITIAL INTENSITY OF 70 KT IS A BLEND OF THE AMSU ESTIMATE AND A DVORAK CURRENT INTENSITY ESTIMATE OF T4.0/65 KT FROM TAFB. DANIELLE APPEARS TO HAVE SLOWED DOWN SOME DURING THE PAST 6 HOURS AND THE MOTION ESTIMATE IS 045/14. WATER VAPOR IMAGERY INDICATES THAT DANIELLE HAS CLEARLY BEEN CAPTURED BY A LARGE MID-/UPPER-LEVEL TROUGH AND THE FLOW PATTERN IS EVOLVING INTO A LARGE MID-LATITUDE CUT-OFF LOW PRESSURE SYSTEM WHICH TYPICALLY MOVES SLOWER THAN A TROPICAL CYCLONE AT THIS LATITUDE. THE GLOBAL MODELS ARE IN FAIR AGREEMENT ON DANIELLE MOVING NORTHEASTWARD OR EVEN EAST- NORTHEASTWARD AT 15-20 KT FOR THE NEXT 2 DAYS OR SO...FOLLOWED BY ACCELERATION TOWARD THE NORTH-NORTHEAST AND THEN NORTHWARD BY DAYS 3 AND 4 AS A LARGER AND STRONGER MID-/UPPER-LEVEL TROUGH MOVES OUT OF NORTHEASTERN CANADA AND ACTS TO KICK OUT THE EXTRATROPICAL DANIELLE CIRCULATION. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY THROUGH 48 HOURS AND IS A BLEND OF THE PREVIOUS TRACK AND THE CONSENSUS MODEL...TVCN...AFTER THAT. DANIELLE IS EXPECTED TO CONTINUE TO WEAKEN AND BECOME FULLY EXTRATROPICAL WITHIN THE NEXT 24 HOURS AS THE HURRICANE MOVES OVER MUCH COOLER WATER THAT LIES NORTH OF 40N LATITUDE. HOWEVER...THE CYCLONE IS EXPECTED TO GET A SHOT OF BAROCLINIC ENERGY BY 72 HOURS FROM THE LARGER MID-/UPPER-LEVEL TROUGH COMING OUT OF CANADA... WHICH WILL HELP THE EX-DANIELLE CIRCULATION REMAIN LARGE AND FAIRLY STRONG OVER THE FAR NORTH ATLANTIC SHIPPING LANES. THE 34-KT WIND RADII REMAIN LARGE AND ARE UNCHANGED BASED ON LIMITED SHIP AND BUOY OBSERVATIONS SURROUNDING THE HURRICANE. 12-FT SEAS RADII WERE SIGNIFICANTLY EXPANDED IN THE SOUTHWESTERN QUADRANT BASED ON GUIDANCE FROM TAFB AND THE OCEAN PREDICTION CENTER. FORECAST POSITIONS AND MAX WINDS INITIAL 30/0300Z 39.3N 53.0W 70 KT 12HR VT 30/1200Z 40.8N 51.2W 60 KT 24HR VT 31/0000Z 42.0N 47.4W 55 KT...POST-TROP/EXTRATROP 36HR VT 31/1200Z 43.5N 42.0W 55 KT...POST-TROP/EXTRATROP 48HR VT 01/0000Z 45.1N 34.0W 60 KT...POST-TROP/EXTRATROP 72HR VT 02/0000Z 51.5N 27.5W 60 KT...POST-TROP/EXTRATROP 96HR VT 03/0000Z 60.0N 30.0W 50 KT...POST-TROP/EXTRATROP 120HR VT 04/0000Z...DISSIPATED $$ FORECASTER STEWART