Tropical Storm MALAKAS Advisory 20 Σεπ.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 18W (MALAKAS) WARNING NR 33//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
    TYPHOON 18W (MALAKAS), LOCATED APPROXIMATELY 159 NM SOUTH OF
IWAKUNI, JAPAN, HAS TRACKED EAST-NORTHEASTWARD AT 17 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS
A SYSTEM THAT HAS WEAKENED SLIGHTLY AFTER MAKING LANDFALL OVER
SOUTHERN KYUSHU. THE POSITION IS BASED ON RECENT SATELLITE AND JMA
RADAR FIXES FROM PGTW AND RJTD WITH GOOD CONFIDENCE. THE INITIAL
INTENSITY IS ASSESSED AT 75 KNOTS AND IS BASED ON DVORAK ESTIMATES
FROM PGTW AND RJTD REPORTING T4.5 (77 KNOTS). RECENT OBSERVATIONS
FROM KANOYA AIR BASE SHOW THE SUSTAINED WINDS REACHED 56 KNOTS WITH
GUSTS UP TO 95 KNOTS AT 191642Z, AS TY MALAKAS PASSED CLOSE TO THE
SOUTH. 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 THROUGH TAU 12, BUT AS TY MALAKAS PASSES THE KII
PENINSULA SSTS WILL DROP CONSIDERABLY FURTHER 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.//
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