Tropical Storm LIONROCK Advisory Tue Aug 30

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W (LIONROCK) WARNING
NR 51//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 12W (LIONROCK), LOCATED APPROXIMATELY 47 NM
WEST-NORTHWEST OF MISAWA, JAPAN, HAS TRACKED NORTH-NORTHWESTWARD AT
32 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY SHOWED THE SYSTEM MAKE LANDFALL JUST NORTH OF
SENDAI, JAPAN AND RAPIDLY ACCELERATE THROUGH NORTHERN HONSHU ALONG
THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYERED SUB-TROPICAL RIDGE TO
THE NORTHEAST. THE STORM HAS BECOME FULLY EMBEDDED WITHIN THE
BOUNDARY LAYER EXTENDING FROM THE SUB-TROPICAL LOW PRESSURE SYSTEM
LOCATED OVER THE SEA OF JAPAN. THE CONVECTIVE SIGNATURE HAS RAPIDLY
DISSIPATED DUE TO THE ELEVATED TERRAIN LOCATED IN NORTHERN JAPAN;
HOWEVER, OBSERVATIONS AT MISAWA AIR BASE SHOWED SUSTAINED 51 KNOT
WINDS WITH GUSTS NEAR 70 KNOTS AS THE SYSTEM PASSED TO THE SOUTH.
THE CURRENT POSITION IS PLACED WITH POOR CONFIDENCE BASED ON A BROAD
LOW LEVEL CIRCULATION CENTER (LLCC) IN THE TOHUKU, JAPAN RADAR LOOP.
THE CURRENT INTENSITY HAS BEEN DECREASED TO REFLECT INCREASED LAND
INTERACTION AFTER THE MISAWA WIND OBSERVATION AND IS SUPPORTED BY
CURRENT INTENSITY ESTIMATES OF 45 KNOTS FROM KNES AND RJTD. TS
LIONROCK IS IN A POOR ENVIRONMENT WITH HIGH (30+ KNOTS) VERTICAL
WIND SHEAR (VWS) DUE TO UPPER LEVEL SOUTHEASTERLY WINDS IN EXCESS OF
50 KNOTS AND INCREASED SUBSIDENCE DUE TO UPPER LEVEL TROUGHING
EXTENDING OVER THE WESTERN AND SOUTHERN PORTIONS OF THE SYSTEM.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY
SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS LIONROCK WILL TURN MORE WESTWARD OVER THE NEXT 12 HOURS AND
MAKE LANDFALL NEAR VLADIVOSTOK, RUSSIA. THE CYCLONE WILL CONTINUE TO
WEAKEN DUE TO THE POOR ENVIRONMENTAL CONDITIONS. TS 12W WILL FULLY
DISSIPATE OVER LAND; HOWEVER, IT WILL CONCURRENTLY UNDERGO EXTRA-
TROPICAL TRANSITION AS IT INTERACTS WITH THE AFOREMENTIONED LOW
PRESSURE SYSTEM. DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT
WHICH LENDS HIGH CONFIDENCE TO THE JTWC FORECAST TRACK.//
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