Tropical Storm HAISHEN Advisory Mon Sep 07

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (HAISHEN)
WARNING NR 027//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 11W (HAISHEN), LOCATED APPROXIMATELY 26 NM NORTH-
NORTHWEST OF BUSAN, SOUTH KOREA, HAS TRACKED NORTHWARD AT 23 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
AND A COMPOSITE RADAR LOOP INDICATE THE SYSTEM HAS RAPIDLY ERODED AFTER
IT MADE LANDFALL AS EVIDENCED BY THE UNRAVELING AND COLLAPSING OF
CONVECTIVE BANDS. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE CIRCULATION FEATURE IN THE RADAR LOOP AND
TRIANGULATION OF NUMEROUS WIND OBSERVATIONS OVER LAND. THE INITIAL
INTENSITY OF 45 KTS IS EXTRAPOLATED FROM AGENCY DVORAK ESTIMATES PRIOR
TO LANDFALL AND FROM THE SURFACE WIND OBSERVATIONS. UPPER LEVEL
ANALYSIS INDICATES A ROBUST POLEWARD OUTFLOW THAT IS OFFSET BY STRONG
(30-KT+) VERTICAL WIND SHEAR. ALSO, THE RUGGED MOUNTAINOUS TERRAIN IS
GREATLY CONTRIBUTING TO THE RAPID EROSION OF THE SYSTEM FROM BELOW. THE
CYCLONE IS TRACKING ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL
RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE LAST PROGNOSTIC REASONING MESSAGE.
   B. TS HAISHEN WILL CONTINUE TO TRACK NORTHWARD THROUGHOUT THE
FORECAST PERIOD UNDER THE STR, MOMENTARILY EXIT INTO THE SEA OF
JAPAN SHORTLY AFTER TAU 06, THEN MAKE A SECONDARY AND FINAL LANDFALL
INTO NORTH KOREA BY TAU 12 BEFORE CROSSING INTO MANCHURIA. THE HOSTILE
ENVIRONMENT, WITH THE ADDITION OF FRICTIONAL EFFECTS OF THE RUGGED
MOUNTAIN RANGES OF THE KOREAN PENINSULA WILL RAPIDLY ERODE AND DISPERSE
THE CONVECTIVE BANDS. CONCURRENTLY, THE SYSTEM HAS ENTERED THE
BAROCLINIC ZONE AND BEGUN EXTRA-TROPICAL TRANSITION AND WILL TRANSFORM
INTO A 30-KNOT COLD-CORE LOW BY TAU 12. NUMERICAL MODELS REMAIN IN
TIGHT AGREEMENT WITH THE EXCEPTION OF AFUM WHICH CONTINUES TO BE AN
EXTREME RIGHT-OF-TRACK OUTLIER AND DRIVES THE VORTEX INTO THE STR.
THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK THAT IS LAID LEFT
OF THE MODEL CONSENSUS TO OFFSET AFUM.//
NNNN
NNNN