msgid/genadmin/navpacmetoccen Pearl Harbor hi/jtwc//
subj/prognostic reasoning for tropical storm 03w warning nr 04//
rmks/
1. For meteorologists.
2. 12 hour summary and analysis.
   A. Tropical Storm (TS) 03w (rammasun) has continued to consolidate
and slowly intensify over the past 12 hours. Although the circulation
remains broad, the system has become better organized and there is
better confidence in the location of the low level center. Animated
multispectral satellite imagery shows improved convective banding
wrapping toward the low level circulation center (LLCC). An anti-
cyclone over the storm continues to provide excellent radial outflow. 
   B. Ts 03w has tracked northwestward along the southwestern peri-
phery of a low to mid-level ridge located to the north-northeast of
the system. The intensity is based on Dvorak estimates of 2.5 from
pgtw and rjtd, as well as Quikscat data displaying 40 knots near the
center of the circulation.
3. Forecast reasoning
   a. The forecast philosophy remains unchanged from the previous
prognostic reasoning, except for extratropical transition of the
system is now forecast to begin prior to tau 120.  
   B. Ts 03w will continue to track northwestward along the south-
western periphery of the subtropical ridge (str) through tau 12.
Beyond this time, the storm will turn northward in response to a
weakness in the str induced by a midlatitude trough transiting north
of the storm. Ts 03w will track northward along the western periphery
of the str through tau 72. All available objective aids remain in
good agreement with this scenario. Ts 03w will continue to steadily
intensify through tau 72 as poleward outflow increases and the storm
tracks over progressively higher ocean heat content. Vertical wind
shear values will remain low through tau 72, which will further aid
in the intensification of the storm. The intensity forecast remains
close to the numerical guidance.
   C. The storm will continue tracking northward along the western
periphery of the str through tau 96. After tau 96, ts 03w will begin
tracking northeastward along the northwestern periphery of the str
and is forecast to begin interacting with a midlatitude trough, which
will deepen as it moves off the coast of eastern China. Ts 03w will
begin to weaken by tau 120 as vertical wind shear increases and ocean
heat content decreases significantly. The storm is expected to begin
extratropical transition prior to tau 120.
Forecast team: Alpha//