WDPN31 PGTW 291500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (KONG-REY) WARNING 
NR 15//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 14W (KONG-REY), LOCATED APPROXIMATELY 100 NM
NORTH-NORTHEAST OF TAIPEI, TAIWAN, HAS TRACKED NORTH-NORTHWESTWARD AT
04 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE (EIR) IMAGERY SHOWS THE DEEP CONVECTION ASSOCIATED WITH THE
SYSTEM HAS DRIFTED FURTHER FROM THE LOW LEVEL CIRCULATION CENTER
(LLCC) AND HAS NOW MOVED INLAND INTO EASTERN CHINA. THE LLCC HAS
BECOME DIFFICULT TO LOCATE ON EIR ANIMATION; HENCE, THE INITIAL
POSITION WAS EXTRAPOLATED, WITH POOR CONFIDENCE, FROM A BROAD LOW
LEVEL FEATURE ON A 290934Z SSMI/S MICROWAVE PASS. THE INITIAL
INTENSITY OF 40 KNOTS WAS AVERAGED FROM THE DVORAK ESTIMATES FROM
PGTW AND RJTD. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM CONTINUES TO
BE SHEARED FROM THE RIDGE THAT IS RECEDING EASTWARD WITH MODERATE
VERTICAL WIND SHEAR (VWS) VALUES (20-25 KNOTS). THE CYCLONE IS NOW
TRACKING ALONG THE WESTERN PERIPHERY OF A LOW REFLECTION OF THE
SUBTROPICAL RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO FORECAST PHILOSOPHY FROM THE PREVIOUS
PROGNOSTIC REASONING BULLETIN. 
   B. TS KONG-REY IS EXPECTED TO BEGIN TRACKING NORTHEASTWARD AS A
MID-LATITUDE TROUGH APPROACHING FROM THE NORTHWEST IS POISED TO
WEAKEN THE STR AND CAUSE THE CYCLONE TO RECURVE AND ACCELERATE. AS TS
14W GETS EMBEDDED IN THE BAROCLINIC ZONE, IT WILL COMMENCE
EXTRA-TROPICAL TRANSITION AFTER TAU 12, BECOMING A COLD CORE LOW BY
TAU 36. THE SYSTEM WILL WEAKEN TO 35 KNOTS BY TAU 12 DUE TO
INCREASING VWS ASSOCIATED WITH THE WESTERLIES. TS 14W WILL THEN MAKE
LANDFALL JUST SOUTH OF SASEBO, KYUSHU, JAPAN AFTER TAU 36. AFTER TAU
48, THE WEAKENED REMNANT LOW WILL BRIEFLY TRANSIT THE SEA OF JAPAN
THEN CROSS THE NORTHERN TIP OF HONSHU AND EXIT INTO THE NORTHWESTERN
PACIFIC BY TAU 72. DYNAMIC MODEL GUIDANCE IS IN POOR AGREEMENT DURING
THE INITIAL 24 HOURS OF THE FORECAST BUT BECOME MORE COHESIVE WITH
BRINGING THE VORTEX OVER NORTHWESTERN JAPAN AFTERWARDS. THERE IS A
DISTINCT POSSIBILITY THAT TS 14W WILL DISSIPATE OVER WATER BEFORE
REACHING KYUSHU DUE TO THE INCREASING VWS. IN VIEW OF THE VARIABILITY
IN THE MODEL FORECAST SOLUTIONS AND THE POSSIBILITY OF PREMATURE
DISSIPATION, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.   //
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