msgid/genadmin/navmarfcstcen Pearl Harbor hi/jtwc//
subj/prognostic reasoning for tropical storm 07w warning nr 23//
rmks/
1. For meteorologists.
2. 12 hour summary and analysis.
A. Tropical Storm (TS) 07w has continued to maintain an intensity 
of 55 knots over the past 12 hours despite moderate to high
vertical wind shear. The low level circulation center (LLCC) has 
remained partially exposed and somewhat broadened to the northeast 
of the bulk of deep convection, as evident in a 232055z trmm 
microwave image. The storm has tracked northwest to north-north-
westward and has picked up speed in the last 6 hours.
B. Detailed analysis of the 700/500mb charts continues to support
a northward trend. The 500 mb chart in particular indicates
the shortwave trough previously located over central to eastern china
has progressed downstream of ts 07w, and has aided in creating a 
well-defined break in the mid-level str to the north of the system
near Hong Kong. This break has allowed ts 07w move progressively 
northward. Animated water vapor imagery shows good equatorward outflow 
and continued northeast to east-northeasterly vws. The current 
position is based on a 232055z trmm 37 ghz image and more recent 
multiple agency position fixes. The current intensity is based on 
Dvorak intensity estimates from pgtw, rjtd and knes indicating a 
55 knot system.
3. Forecast reasoning
a. There have been significant changes to the forecast track and Phil-
osophy over the past 12 hours. The system is now expected to track 
northward longer than previously anticipated and make landfall 
with Mainland China between tau 12 and 24. As a result, the system 
will rapidly degrade over land prior to completing recurvature and
extratropical transition. 
B. The system will track generally northward towards China, and will
make landfall to the east of Hong Kong between tau 12 and 24. Prior
to making landfall the system will undergo slight weakening to 
account for low ocean heat content. Once ashore the system will 
weaken considerably and will fully dissipate over land as a 
significant tropical system by tau 48. However, the system will be 
closely monitored for the unlikely possibility of redevelopment 
in the East China Sea beyond tau 72, as some model guidance suggests.
Forecast team: Alpha/