Show Selection: |
#37335 (Received by flhurricane at: 4:37 AM 04.Aug.2005) TCDAT3 TROPICAL STORM HARVEY DISCUSSION NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT THU AUG 04 2005 AIR FORCE RECON FOUND A LOWER CENTRAL PRESSURE...995 MB... BUT SO FAR THE HIGHEST 850 MB FLIGHT LEVEL WINDS MEASURED BY THE AIRCRAFT DO NOT SUPPORT AN INCREASE IN STRENGTH. CURRENT INTENSITY IS HELD AT 50 KT. DEEP CONVECTION ASSOCIATED WITH THE TROPICAL CYCLONE HAS INCREASED OVER THE PAST FEW HOURS. ALTHOUGH HARVEY IS BEING AFFECTED BY ABOUT 20 KT OF WEST-SOUTHWESTERLY SHEAR...IT IS HOLDING ITS OWN...AS IS TYPICAL OF THESE HIGHER LATITUDE SYSTEMS. SOME SLIGHT INCREASE IN STRENGTH IS POSSIBLE OVER THE NEXT DAY OR SO...BUT SIGNIFICANT INTENSIFICATION IS UNLIKELY. THE CYCLONE SHOULD BE WEAKENING OVER COOLER WATERS IN THE LATTER PART OF THE FORECAST PERIOD. THE GFS MODEL SHOWS HARVEY'S CIRCULATION BECOMING ELONGATED IN 3-5 DAYS...SUGGESTING THAT IT MAY LOSE TROPICAL CHARACTERISTICS LATE IN THE PERIOD. HARVEY IS MOVING AT ABOUT 070/11. A SHORTWAVE TROUGH NEAR 60W IS MOVING AWAY FROM THE STORM SO THE STEERING CURRENT WILL PROBABLY WEAKEN OVER THE NEXT COUPLE OF DAYS...UNTIL ANOTHER APPROACHING TROUGH ACCELERATES THE WEST-SOUTHWESTERLY FLOW LATER IN THE PERIOD. THIS NEXT TROUGH...HOWEVER...WILL NOT HAVE MUCH AMPLITUDE SO IT SEEMS UNLIKELY TO BE ABLE TO CAUSE A BIG INCREASE IN HARVEY'S FORWARD SPEED. THE CONSENSUS OF THE TRACK GUIDANCE IS GENERALLY SLOWER THAN IN THE EARLIER RUNS...SO THE OFFICIAL FORECAST IS A LITTLE SLOWER THAN THE PREVIOUS ONE. THIS IS A COMPROMISE BETWEEN THE U.K. MET AND GFS...WHICH ARE SIGNIFICANTLY SLOWER THAN MY FORECAST...AND THE NOGAPS AND GFDL...WHICH ARE CONSIDERABLY FASTER. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 04/0900Z 31.8N 64.6W 50 KT 12HR VT 04/1800Z 32.2N 62.8W 55 KT 24HR VT 05/0600Z 32.6N 60.8W 55 KT 36HR VT 05/1800Z 32.9N 59.5W 50 KT 48HR VT 06/0600Z 33.3N 58.3W 45 KT 72HR VT 07/0600Z 35.0N 55.5W 40 KT 96HR VT 08/0600Z 37.5N 51.5W 35 KT 120HR VT 09/0600Z 40.0N 47.0W 30 KT |