MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (NANGKA) WARNING
NR 54//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 11W (NANGKA), LOCATED APPROXIMATELY 96 NM
EAST OF IWAKUNI, JAPAN, HAS TRACKED NORTH-NORTHWESTWARD AT 11 KNOTS
OVER THE PAST SIX HOURS. ANIMATED COMPOSITE RADAR REFLECTIVITY FROM
THE JAPAN METEOROLOGICAL AGENCY SHOWS THE SYSTEM HAS MADE LANDFALL
AND IS NOW DRAGGING ACROSS THE NORTHERN TIP OF SHIKOKU. THE
CONVECTION ASSOCIATED WITH 11W HAS GREATLY DIMINISHED, AS INDICATED
BY THE RADAR LOOP AND BY IR SATELLITE IMAGERY. THE INITIAL POSITION
IS BASED ON RADAR ANIMATION WITH HIGH CONFIDENCE. THE INITIAL
INTENSITY OF 50 KNOTS IS EXTRAPOLATED FROM NEARBY SURFACE
OBSERVATIONS. THE SYSTEM IS CURRENTLY ROUNDING THE WESTERN EDGE OF
THE STR TO THE EAST.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TS NANGKA WILL CONTINUE TRACKING GENERALLY NORTHWARD AND EXIT
INTO THE SEA OF JAPAN BY TAU 12. AFTERWARDS, IT WILL ACCELERATE
NORTHEASTWARD WITH THE MID-LATITUDE WESTERLIES, CROSS THE NORTHERN
TIP OF HONSHU AND RETURN TO THE PACIFIC OCEAN JUST EAST OF HOKKAIDO
BY TAU 72. THE SYSTEM WILL RAPIDLY DECAY WITH INCREASING VWS, COLD
ALONG-TRACK SSTS IN THE SEA OF JAPAN (BELOW 26 CELSIUS), AND LAND
INTERACTION OVER NORTHERN HONSHU. TS 11W WILL DISSIPATE BY TAU 72.
NUMERIC MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT LEADING TO HIGH
CONFIDENCE IN THE JTWC FORECAST TRACK.//
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