Tropical Storm 24W (Maysak)
Tropical Storm 24W has intensified over the past 12 hours due to improved poleward outflow ahead of an approaching midlatitude shortwave trough. The system has turned more poleward along the western periphery of the low to mid-level subtropical ridge (STR). The dynamic models with the exception of GFDN and WBAR continue to indicate rapid weakening, quasi-stationary or slow movement, and aneventual southward track. However, the timing of these stages varies and represents the primary forecast challenge.
Tropical Storm 24W is currently tracking under the steering influence of the low to mid-level STR situated east of the system as depicted in the recent 700-500 mb analyses. Animated water vapor imagery indicates that poleward outflow has improved ahead of the midlatitude shortwave trough tracking across eastern china. the current position is based on a 080958z 37 ghz coriolis image, which depicted a well-defined low-level circulation center (LLCC) with improved convective banding wrapping into the northwest quadrant, and recent satellite fixes.
There is good confidence in both positioning and 12-hour motion. The current intensity is based on Dvorak estimates of 55 knots. The general forecast philosophy has not changed, however, the track reflects a more poleward, faster motion (current and forecast) through tau 24.
The major shortwave trough currently over eastern China is expected to continue tracking eastward and will begin to affect the system within the next 24 hours. Strong vertical wind shear (VWS) due to a combination of upper-level southwesterlies and low-level north-easterlies are expected to rapidly weaken the system after tau 36and produce a southward turn. The bulk of the dynamic model guidance is in agreement on the general track forecast philosophy with minor timing differences producing slight variations in the southward turn.