Show Selection: |
#3384 (Received by flhurricane at: 4:36 PM 01.Aug.2004) TCDAT1 TROPICAL STORM ALEX DISCUSSION NUMBER 5 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT SUN AUG 01 2004 THE RECONNAISSANCE AIRCRAFT INVESTIGATING THE DEPRESSION EARLY THIS AFTERNOON FOUND 41 KT WINDS IN THE SOUTHEAST QUADRANT AT A FLIGHT LEVEL OF 1000 FT...WHICH ADJUSTS TO ABOUT 33 KT AT THE SURFACE. THE CREW ALSO ESTIMATED THE SUSTAINED SURFACE WINDS TO BE 35 KT. ON THIS BASIS...THE DEPRESSION WAS UPGRADED TO A TROPICAL STORM AT 18Z. FIXES FROM THE AIRCRAFT SHOWED THAT THE CENTER IS MOVING LITTLE AND LIES JUST NORTH OF THE AREA OF DEEP CONVECTION. THERE ARE OTHER SIGNS THAT THE CYCLONE STRUCTURE IS IMPROVING...WITH A CIRCULATION THAT APPEARS TO BE LESS ELONGATED THAN IT WAS EARLIER IN THE DAY...MULTIPLE SWIRLS NOTWITHSTANDING...AND THE DEVELOPMENT OF A LITTLE OUTFLOW TO THE NORTHWEST OF THE DEEP CONVECTION. THIS LATTER TREND IS LIKELY THE PRECURSOR TO A SOMEWHAT MORE FAVORABLE UPPER AIR PATTERN OVER THE NEXT 24 HOURS...AS ALEX COMES UNDERNEATH SOME ANTICYCLONIC FLOW BEFORE THE SOUTHWESTERLIES ARRIVE. CONSEQUENTLY...SOME STRENGTHENING APPEARS IN THE OFFICIAL INTENSITY FORECAST. THE SHIPS INTENSITY GUIDANCE IS MORE AGGRESSIVE... BRINGING ALEX TO NEAR 60 KT IN 36 HOURS. AS THE UPPER FLOW CHANGES...ALEX WILL LIKELY BECOME SOMEWHAT MORE SYMMETRIC IN ITS CONVECTIVE PATTERN AND WIND FIELD. THE INITIAL MOTION IS STATIONARY. MODEL GUIDANCE IS IN GOOD AGREEMENT THAT A NORTHEASTWARD MOTION SHOULD BEGIN SOON...BUT THE MODELS WILL PROBABLY UNDERESTIMATE THE DRAG OF THE CURRENT CONVECTIVE ASYMMETRY. DUE TO THE STATIONARY MOTION TODAY...THERE IS MORE TIME FOR ALEX TO BE CAUGHT UP IN THE APPROACHING SOUTHWESTERLY FLOW. AS A RESULT...THE OFFICIAL FORECAST HAS BEEN NUDGED SLIGHTLY TO THE RIGHT OF THE PREVIOUS TRACK AND TOWARD THE CONSENSUS OF THE DYNAMICAL GUIDANCE. NEVERTHELESS...THE CENTER IS STILL EXPECTED TO COME VERY CLOSE TO THE COASTLINE. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 01/2100Z 31.7N 79.2W 35 KT 12HR VT 02/0600Z 32.4N 78.9W 40 KT 24HR VT 02/1800Z 33.5N 77.8W 45 KT 36HR VT 03/0600Z 34.7N 75.7W 45 KT 48HR VT 03/1800Z 36.5N 72.5W 45 KT 72HR VT 04/1800Z 41.0N 64.0W 45 KT 96HR VT 05/1800Z 46.0N 52.0W 45 KT...EXTRATROPICAL 120HR VT 06/1800Z...ABSORBED BY EXTRATROPICAL LOW |