Tropical Storm KAI-TAK Advisory Sa, 14.08.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (KAI-TAK) WARNING
NR 06 RELOCATED//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TROPICAL STORM (TS) 14W (KAI-TAK), LOCATED APPROXIMATELY 400 NM
EAST-NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD
AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY INDICATES DEEP CONVECTION ALONG THE SOUTHWESTERN
PERIPHERY OF A LOW-LEVEL CIRCULATION CENTER (LLCC). THE INITIAL
POSITION IS BASED ON A CENTER OF MASS POSITION FROM A COMBINATION OF
A 131454Z OSCAT IMAGE, PGTW AND RJTD FIXES, A 131405Z TRMM 85 GHZ
IMAGE, AND THE ABOVEMENTIONED EIR SATELLITE IMAGERY WITH LOW
CONFIDENCE. INITIAL INTENSITY IS BASED ON A PGTW DVORAK INTENSITY
ESTIMATE OF 45 KNOTS AS WELL AS 45 KNOT UNFLAGGED WIND BARBS ON THE
131454Z OSCAT IMAGE. TS 14W LIES EQUATORWARD OF AN UPPER-LEVEL RIDGE
AXIS IN AN AREA OF LOW TO MODERATE (10-20 KNOT) VERTICAL WIND SHEAR
(VWS) AND STRONG EQUATORWARD OUTFLOW. RECENT WATER VAPOR SATELLITE
IMAGERY ALSO SHOWS POLEWARD OUTFLOW TOWARD A WEAK TROPICAL UPPER
TROPOSPHERIC TROUGH (TUTT) POSITIONED NORTHEAST OF OKINAWA. THE
CYCLONE CONTINUES TO TRACK WEST-NORTHWESTWARD ALONG THE SOUTHERN
PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE. A 131200Z UPPER LEVEL
SOUNDING FROM ISHIGAKI-JIMA CONFIRMS EASTERLY FLOW AT ALL LEVELS.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE, HOWEVER THE 131200Z POSITION, AS WELL
AS THE BEST TRACK POSITIONS FROM THE PAST 48 HOURS, HAVE BEEN
CHANGED BASED ON NEWLY AVAILABLE MICROWAVE AND SCATTEROMETRY DATA.
   B. TS 14W IS EXPECTED TO CONTINUE TRACKING WEST-NORTHWESTWARD
ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE TO
THE NORTH DURING THE NEXT 72 HOURS. MODERATE VWS IS EXPECTED TO
RELAX SOMEWHAT AS THE STORM TRACKS TOWARD SOUTHERN TAIWAN OVER WARM
SEA SURFACE TEMPERATURES (> 28 DEGREES CELSIUS). THIS WILL ALLOW TS
14W TO SLOWLY INTENSIFY. AT TAU 48, KAI-TAK IS EXPECTED TO ENTER A
REGION OF LIGHT (5-10 KNOT) VWS, ALLOWING FOR INTENSIFICATION.
HOWEVER, THE SYSTEM COULD BEGIN INTERACTING WITH THE TERRAIN OF
TAIWAN, POTENTIALLY DECREASING INTENSITY. THEREFORE THERE IS LOW
CONFIDENCE IN THE PEAK INTENSITY OF THIS STORM. AFTER TAU 48, 14W
WILL ENTER A REGION OF INCREASING VWS (10-20 KNOTS) AND DECREASING
OCEAN HEAT CONTENT, RESULTING IN FURTHER WEAKENING BEFORE LANDFALL.
   C. AT TAU 72, KAI-TAK IS EXPECTED TO MAKE LANDFALL IN
SOUTHEASTERN CHINA AS IT CONTINUES TO TRACK ALONG THE SOUTHERN
PERIPHERY OF THE CURRENT STEERING RIDGE. TS 14W IS EXPECTED TO
DISSIPATE AFTER MAKING LANDFALL. THE NUMERICAL MODELS ARE IN GOOD
AGREEMENT, WITH THE EXCEPTION OF NOGAPS, WHICH TRACKS 14W OVER
TAIPEI BEFORE MAKING LANDFALL IN CHINA NEAR 27N. WBAR REMAINS THE
LEFT OUTLIER IN EARLY TAUS WITH ECMWF SLIGHTLY LEFT OF THE GUIDANCE
PACKAGE AFTER TAU 48. THIS FORECAST LIES SLIGHTLY EQUATORWARD AND
FASTER THAN THE NUMERICAL MODEL CONSENSUS, CONSISTENT WITH CURRENT
ANALYSIS AND PROGNOSIS OF THE STEERING PATTERN. BASED ON CONSISTENT
AGREEMENT OF THE OBJECTIVE AID PACKAGE, TRACK FORECAST CONFIDENCE IS
HIGH.//
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