msgid/genadmin/navpacmetoccen Pearl Harbor hi/jtwc//
subj/prognostic reasoning for tropical storm 15w warning nr07/
rmks/ 
1. For meteorologists.
2. 12 hour summary and analysis.
   A. Tropical Storm (TS) 15w (Francisco) has weakened over
the past 06 hours and the low level circulation center has
become partially exposed as the convection is being sheared to
the west-southwest. The primary steering influence continues
to be the west to east oriented low to mid-level subtropical
ridge located north of Taiwan, which has led to a continued
westward track over the past 12 hours.
   B. Ts 15w is located approximately 210 nm east-southeast of
hanoi, Vietnam. The current position is based on enhanced infrared
satellite fixes from pgtw and rjtd and a 241203z ssmis image. The
current intensity is based on Dvorak estimates of 30 to 45 knots.
Ts 15w has tracked westward at 11 knots over the past 06 hours.
3. Forecast reasoning.
   A. The forecast philosophy remains the same as the previous
prog reasoning, except that the forecast intensities have been
decreased due to the quicker weakening of the system than
previously forecast.
   B. The low to mid-level steering ridge will remain north of
ts 15w throughout the forecast period. This steering influence
will lead to a continued westward track across northern hainan
and then into the Gulf of Tonkin before landfall over northern
Vietnam prior to tau 24. As the storm continues to track across
hainan, land interaction will continue to impact the storm over
the first 06 hours of the forecast. After this time, the storm
will reemerge over the Gulf of Tonkin. Despite the continued
moderate vertical wind shear, the warm waters and good poleward
outflow will allow the storm to remain a minimal tropical storm.
Ts 15w will weaken after landfall along the coast of northern
Vietnam prior to tau 24. Ts 15w will dissipate completely prior
to tau 36. The available dynamic aids remain in good agreement
with this scenario.
Forecast team: Bravo/