Tropical Storm MALAKAS Advisory Di, 20.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 18W (MALAKAS) WARNING NR 34//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
    TYPHOON 18W (MALAKAS), LOCATED APPROXIMATELY 113 NM SOUTHEAST OF
IWAKUNI, JAPAN, HAS TRACKED NORTHEASTWARD AT 21 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS
A SYSTEM THAT HAS WEAKENED BUT HAS MAINTAINED RELATIVELY ORGANIZED
OVER THE LAST SIX HOURS AS IT HAS SKIRTED THE ISLAND OF SHIKOKU. THE
INITIAL POSITION IS BASED ON JMA RADAR FIXES AND SATELLITE FIXES
FROM PGTW AND RJTD WITH GOOD CONFIDENCE. THE INITIAL
INTENSITY IS ASSESSED AT 65 KNOTS AND IS BASED ON AN AVERAGE FROM
ALL AGENCIES REPORTING DVORAK ESTIMATES RANGING FROM T4.5 TO T3.5
(55 TO 77 KNOTS). A 200100Z OBSERVATION FROM MUROTO-MISAKI, LOCATED
NEAR THE TYPHOON CENTER, INDICATED SUSTAINED WINDS FROM THE EAST-
SOUTHEAST AT 60 KNOTS. UPPER-LEVEL ANALYSIS SHOWS INCREASING VALUES
OF WIND SHEAR ASSOCIATED WITH THE WESTERLY JET AND A SHORTWAVE
TROUGH MOVING IN FROM THE NORTHWEST. SEA SURFACE TEMPERATURES ARE
FAVORABLE NEAR 28 CELSIUS. CURRENTLY TY MALAKAS IS TRAVELING  EAST-
NORTHEAST ALONG THE NORTHWESTERN PERIPHERY OF A DEEP-LAYERED
SUBTROPICAL RIDGE LOCATED TO THE SOUTHWEST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY MALAKAS WILL CONTINUE TO TRACK NORTH-NORTHEAST UNDER THE
INFLUENCE OF THE CURRENT STEERING RIDGE ALONG THE SHORELINE OF
SOUTHERN JAPAN. THE CLOSE PROXIMITY TO LAND WILL DISRUPT THE LOW-
LEVEL WIND FLOW THROUGHOUT THE FORECAST PERIOD. THIS IN CONJUNCTION
WITH RISING SHEAR VALUES WILL SERVE TO WEAKEN THE SYSTEM. SSTS WILL
REMAIN FAVORABLE FOR THE IMMEDIATE FUTURE, BUT AS TY MALAKAS PASSES
THE KII PENINSULA, SSTS WILL DROP CONSIDERABLY, CONTRIBUTING
TO THE WEAKENING TREND. TY MALAKAS IS FORECAST TO DISSIPATE BY TAU
48. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 24, BUT
START TO DIVERGE SOMEWHAT AFTER TY MALAKAS PASSES YOKOSUKA, JAPAN
DUE TO A DRASTICALLY WEAKENED SYSTEM, LENDING HIGH CONFIDENCE TO THE
FORECAST TRACK.//
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