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| #218833 (Received by flhurricane at: 5:03 PM 26.Sep.2008) TCDAT1 TROPICAL STORM KYLE DISCUSSION NUMBER 5 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112008 500 PM EDT FRI SEP 26 2008 REPORTS FROM AIR FORCE AND NOAA RESERVE HURRICANE HUNTER AIRCRAFT INDICATE THAT KYLE IS SOMEWHAT DISORGANIZED THIS AFTERNOON...WITH THE FLIGHT-LEVEL CENTERS AT 850 MB AND 700 MB DISPLACED TO THE NORTH OR NORTHEAST OF THE SURFACE CENTER BY 15-20 KT OF WESTERLY VERTICAL WIND SHEAR. THE CENTRAL PRESSURE HAS RISEN TO 1003 MB...AND THE CONVECTIVE PATTERN HAS BECOME ELONGATED NORTH- NORTHWEST TO SOUTH-SOUTHEAST IN SATELLITE IMAGERY. THE AIR FORCE AIRCRAFT REPORTED 56 KT FLIGHT-LEVEL WINDS AT 850 MB...WITH SFMR WINDS OF 45-48 KT IN THE NORTHEAST QUADRANT. BASED ON THIS...THE INITIAL INTENSITY REMAINS 50 KT. AFTER A NUDGE TO THE LEFT THIS MORNING...KYLE HAS MADE A NUDGE TO THE RIGHT THIS AFTERNOON. THE 12 HR MOTION AND ADVISORY MOTION IS 345/11...BUT THE SHORT-TERM MOTION IS ALMOST DUE NORTH. KYLE REMAINS ON THE SOUTHWEST SIDE OF A BUILDING RIDGE OVER THE CENTRAL ATLANTIC...AND SOON SHOULD PASS BETWEEN THE RIDGE AND A DEEP-LAYER LOW PRESSURE AREA OVER THE EASTERN UNITED STATES. THIS PATTERN SHOULD STEER KYLE GENERALLY NORTH-NORTHWESTWARD AND NORTHWARD FOR THE NEXT 24-36 HR. AFTER THAT...THE GUIDANCE FORECASTS KYLE TO TURN MORE TOWARD THE NORTH-NORTHEAST AS IT APPROACHES THE MAIN BRANCH OF THE WESTERLIES AND THE NORTHERN END OF THE ATLANTIC RIDGE. THE MODEL GUIDANCE HAS SHIFTED A LITTLE TO THE RIGHT TOWARD WESTERN NOVA SCOTIA OVER THE PAST 6 HOURS...WITH MOST OF GUIDANCE NOW SHOWING A SLIGHTLY SLOWER FORWARD MOTION THAN PREVIOUSLY. BASED ON THE NEW GUIDANCE AND THE INITIAL POSITION/MOTION...THE NEW FORECAST TRACK IS SHIFTED A LITTLE TO THE EAST OF THE PREVIOUS TRACK. HOWEVER...IT LIES ALONG THE WESTERN EDGE OF THE MODEL CONSENSUS. IF ANYTHING...THE INTENSITY FORECAST HAS BECOME MORE COMPLEX THAN IT WAS 6 HOURS AGO. THE CURRENT SHEAR MAY DECREASE SOMEWHAT OVER THE NEXT 24 HOURS...WHICH WOULD ALLOW KYLE TO GRADUALLY INTENSIFY. AFTER THAT...KYLE IS FORECAST TO ENCOUNTER STRONG...BUT DIVERGENT...UPPER-LEVEL SOUTHWESTERLY FLOW....WITH THE RESULTING SHEAR TRYING TO WEAKEN THE CYCLONE AND THE DIVERGENCE TRYING TO STRENGTHEN IT. A NEW COMPLICATION IS A COLD AIR MASS APPROACHING KYLE FROM THE EAST...WHICH IF IT REACHES THE CYCLONE COULD CAUSE WEAKENING OR A FASTER EXTRATROPICAL TRANSITION. DESPITE THE NEGATIVE FACTORS...THE SHIPS...HWRF...AND GFDL MODELS CALL FOR KYLE TO BECOME A HURRICANE. THE NEW INTENSITY FORECAST THUS CALLS FOR THE CYCLONE TO REACH A PEAK INTENSITY OF 65 KT IN 36 HR. AFTER THAT TIME...KYLE WILL MOVE OVER COLD SEA SURFACE TEMPERATURES AND BEGIN EXTRATROPICAL TRANSITION...AND THIS COMBINATION SHOULD CAUSE WEAKENING. KYLE SHOULD LOSE TROPICAL CHARACTERISTICS AFTER LANDFALL AND EVENTUALLY BE ABSORBED IN A FRONTAL SYSTEM IN A FRONTAL SYSTEM OVER EASTERN CANADA. INTERESTS IN EASTERN NEW ENGLAND AND THE CANADIAN MARITIMES SHOULD CLOSELY MONITOR THE PROGRESS OF KYLE. WATCHES MAY BE REQUIRED FOR PORTIONS OF THE NEW ENGLAND COAST ON SATURDAY. FORECAST POSITIONS AND MAX WINDS INITIAL 26/2100Z 27.6N 68.7W 50 KT 12HR VT 27/0600Z 29.5N 69.3W 55 KT 24HR VT 27/1800Z 32.6N 69.5W 60 KT 36HR VT 28/0600Z 36.5N 69.0W 65 KT 48HR VT 28/1800Z 40.3N 67.8W 65 KT 72HR VT 29/1800Z 47.5N 64.5W 45 KT...EXTRATROPICAL 96HR VT 30/1800Z 52.0N 62.0W 35 KT...INLAND EXTRATROPICAL 120HR VT 01/1800Z...ABSORBED BY FRONTAL SYSTEM $$ FORECASTER BEVEN |
