Wdpn31 Pgtw 200300 

msgid/genadmin/navpacmetoccen Pearl Harbor hi/jtwc// 

subj/prognostic reasoning for typhoon 02w warning nr 15//
rmks/
1. For meteorologists.
2. Prognostic reasoning for 200000z may to 220000z may 2007.
   A. Typhoon (TY) 02w (Yutu), located approximately 580 nm
southwest of Iwo Jima, has tracked northeastward at 10 knots
over the past six hours. TY 02w has maintained an eye for the
past 12 hours, but it has become ragged and the intensity of
the system has decreased slightly over the past six hours due
to the offsetting influences of good poleward outflow and
increased vertical wind shear.
   B. TY 02w is currently tracking along the northwestern
periphery of the subtropical ridge (str) anchored north and
east of the Mariana islands. The system has begun to slowly
accelerate to the northeast after briefly slowing as it crested
the ridge axis. TY 02w will continue to accelerate to the
northeast as it increasingly interacts with the midlatitude
westerlies and a trough that is oriented northeast to southwest
currently located over Japan. The system will begin extra-
tropical transition prior to tau 36, ahead of a secondary
trough that is currently located west of Taiwan. TY 02w will
become imbedded in this trough and become fully extratropical
before tau 48.
   C. TY 02w will slowly weaken over the next 12 to 24 hours.
After this time, the storm weaken more rapidly under the
effects of higher vertical wind shear and lower sea surface
temperatures. The storm will begin extratropical transition
by tau 36 and become a fully extratropical system with
tropical storm force winds near tau 48. 
   D. Current wind radii are based on estimates derived from
microwave satellite imagery and convective signature. Forecast
wind radii are based on climatology for an average-sized system
and analysis of wind field distortions typically associated with
extratropical transition.
Forecast team: Bravo//