subj/prognostic reasoning for typhoon 10w warning nr26//
rmks/
1. For meteorologists.
2. 12 hour summary and analysis.
   A. Typhoon (TY) 10w (Fitow) has tracked westward at 09 knots
over the past 06 hours and weakened slightly. Model consistency
has been excellent with the exception of the GFS tracker which
has been erratic over the past five runs.  
   B. The current position is based on a well-defined low-level
circulation center (LLCC) with tightly-curved convective banding
evident in a 032248z trmm image and recent visible imagery. The
current intensity is based on Dvorak estimates ranging from 65
to 77 knots. TY 10w is currently 60nm east-northeast of chichi
jima with Max winds observed at 45 knots with minimum sea level
pressure near 986 mb. TY 10w is tracking under the steering
influence of the 500 mb subtropical ridge that is centered south
of Tokyo. Animated water vapor imagery depicts fair outflow
overall with no indication that the system has tapped into the
midlatitude westerlies yet. 
3. Forecast reasoning.
   A. There have been no major changes in forecast reasoning.
   B. The 03/12z upper air analyses depict a broad 500 mb trough
situated over east Asia and the East China Sea. This trough is
tracking eastward at 10-12 knots and is forecast to continue to
erode the ridge north of the system over the next 24-48 hours.
This will allow TY 10w to re-curve and accelerate northward. Ty
10w is forecast to intensify from tau 24 to tau 48 due to
improved poleward outflow enhanced by the midlatitude westerlies.  
The available dynamic aids are in good agreement through tau 48
but diverge slightly after this time as the system begins to
interact with the midlatitude westerlies and begin extra-tropical
transition. The GFS model is the western outlier and is having
problems handling the system after tau 48. In particular, the
tracker is jumping to a midlatitude disturbance after tau 60,
therefore, the tracker is suspect and the official forecast
is hedged slightly right of conw and slightly faster. 
  C. After making landfall near tau 60, TY 10w is forecast to
rapidly weaken due to land interaction and increased vertical
wind shear. TY 10w is forecast to complete extra-tropical
transition prior to approaching Misawa ab. The system is forecast
to track north-northeastward on the northwest periphery of the
broad 700-500 mb ridge. The available models continue to diverge
and as mentioned earlier, the official forecast favors a re-
curvature east of northern honshu in line with the bulk of the
reliable model trackers. 
Forecast team: Bravo//