WDPN31 PGTW 011500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (MAYSAK) WARNING
NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 10W (MAYSAK), LOCATED APPROXIMATELY 427 NM
SOUTH-SOUTHWEST OF BUSAN, SOUTH KOREA, HAS TRACKED NORTHWARD
AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED
INFRARED (EIR) SATELLITE IMAGERY DEPICTS DEEP CONVECTION
AND SPIRAL BANDING WRAPPING TIGHTLY INTO A LOW LEVEL
CIRCULATION CENTER (LLCC). THE EYE FEATURE HAS FILLED SLOWLY
OVER THE PAST 6 HOURS. THE INITIAL POSITION IS PLACED WITH
HIGH CONFIDENCE BASED ON THE REMNANTS OF THE EYE PRESENT IN
THE EIR LOOP, AS WELL AS A MICROWAVE EYE FEATURE PRESENT IN
A 010730Z SSMIS 91 GHZ IMAGE. THE INITIAL INTENSITY OF 120
KTS IS PLACED WITH HIGH CONFIDENCE AND IS HEDGED BETWEEN
MULTIAGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T6.0 (115
KTS, RJTD) AND T6.5 (127 KTS, PGTW), SLIGHTLY ABOVE A 011150Z
CIMSS SATCON INTENSITY ESTIMATE OF 118 KTS AND IN AGREEMENT
WITH A CIMSS ADVANCED DVORAK TECHNIQUE CURRENT INTENSITY
ESTIMATE OF T6.2 (120 KTS). THE ENVIRONMENT CONTINUES TO BE
FAVORABLE WITH ROBUST, RADIAL OUTFLOW ALOFT, WARM (29-30
CELSIUS) SEA SURFACE TEMPERATURES (SST) AND CONTINUED HIGH
OCEAN HEAT CONTENT (50-60 JOULES PER SQUARE CENTIMETER),
HOWEVER VERTICAL WIND SHEAR (VWS) HAS INCREASED MODERATELY
(10-15 KTS). FURTHERMORE, ANALYSIS OF THE CONVECTIVE
STRUCTURES IN MICROWAVE IMAGERY REVEALS THAT AN EYE-WALL
REPLACEMENT CYCLE (ERC) HAS COMMENCED WHICH HAS LEAD TO
FURTHER WEAKENING OVER THE PAST 6 HOURS. TY MAYSAK IS
TRACKING UNDER THE COMBINED STEERING INFLUENCE OF TWO
SUBTROPICAL RIDGES (STR) AND IS CURRENTLY ROUNDING THE
PRIMARY STEERING RIDGE AXIS POSITIONED TO THE SOUTHEAST.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TY MAYSAK WILL TRACK POLEWARD AFTER ROUNDING THE AXIS OF
THE STEERING RIDGE AND WILL CONTINUE WEAKENING DUE TO DECREASING
SST AND INCREASING VWS THROUGHOUT THE REMAINDER OF THE FORECAST
PERIOD. BY TAU 12, THE SYSTEM WILL WEAKEN TO 105 KTS, AND FURTHER
TO 95 KTS BY TAU 24 DUE TO THE DEGRADING ENVIRONMENTAL CONDITIONS
AND THE EFFECTS OF THE ERC. AFTER TRACKING GENERALLY NORTHWARD
THROUGH TAU 24, THE SYSTEM WILL MAKE LANDFALL ON THE SOUTHERN
COAST OF SOUTH KOREA WEST OF BUSAN. TY MAYSAK WILL THEN CONTINUE
TO WEAKEN TO 70 KTS BY TAU 36 AS IT MOVES INLAND DUE TO THE
FRICTIONAL EFFECTS OF LAND AND VERY HIGH (> 50 KTS) VWS. THE
SYSTEM WILL BEGIN EXTRATROPICAL TRANSITION (ETT) AS IT BECOMES
EMBEDDED IN THE BAROCLINIC ZONE AT THAT TIME. AFTER TAU 36 THE
SYSTEM WILL CONTINUE TO WEAKEN AND COMPLETE ETT BY TAU 48 AS IT
BEGINS TO INTERACT WITH A MIDLATITUDE TROUGH APPROACHING FROM
THE NORTHWEST. THERE IS A DISTINCT POSSIBILITY OF DISSIPATION
OVER THE RUGGED TAEBAEK MOUNTAIN RANGES PRIOR TO TAU 72.
NUMERICAL MODEL SOLUTIONS REMAIN IN TIGHT AGREEMENT, WITH THE
JTWC FORECAST TRACK PLACED WEST OF THE MULTI-MODEL CONSENSUS TO
OFFSET THE AFUM TRACK, WHICH CONTINUES TO BE THE EXTREME RIGHT-
OF-TRACK OUTLIER THAT IS UNREALISTICALLY DRIVING THE VORTEX INTO
THE STR. THE TIGHT AGREEMENT OF NUMERICAL MODEL SOLUTIONS
THROUGHOUT THE FORECAST PERIOD LENDS OVERALL HIGH CONFIDENCE IN
THE JTWC FORECAST TRACK.//
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