Tropical Storm MAYSAK Advisory Wed Sep 02

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (MAYSAK) WARNING
NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 10W (MAYSAK), LOCATED APPROXIMATELY 475 NM
SOUTH-SOUTHWEST OF BUSAN, SOUTH KOREA, HAS TRACKED NORTHWARD
AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) DEPICTS SPIRAL BANDING WRAPPING
TIGHTLY INTO AN APPROXIMATELY 10 NM DIAMETER EYE. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
EYE PRESENT IN BOTH THE MSI AND COMPOSITE RADAR LOOPS, AS WELL
AS IN AN 010501Z AMSR2 36 GHZ IMAGE. THE INITIAL INTENSITY OF
125 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 CONSISTENT
CIMSS ADVANCED DVORAK TECHNIQUE CURRENT INTENSITY ESTIMATES OF
T6.3 (122 KTS) AND SLIGHTLY UNDER A TIMELY 010450Z SATCON
ESTIMATE OF 128 KTS. THE ENVIRONMENT CONTINUES TO BE FAVORABLE
WITH ROBUST, RADIAL OUTFLOW ALOFT, LOW (5-10 KTS) VERTICAL WIND
SHEAR (VWS), WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES
(SST) AND CONTINUED HIGH OCEAN HEAT CONTENT (50-60 JOULES PER
SQUARE CENTIMETER). 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 EAST.
   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 BEGIN WEAKENING DUE TO DECREASING
SST AND INCREASING VWS THROUGHOUT THE REMAINDER OF THE FORECAST
PERIOD. BY TAU 12, THE SYSTEM WILL WEAKEN TO 115 KTS, AND
FURTHER TO 100 KTS BY TAU 24 DUE TO THE DEGRADING ENVIRONMENTAL
CONDITIONS. FURTHERMORE, ANALYSIS OF THE EYE WALL STRUCTURE IN
MICROWAVE IMAGERY SUGGESTS THAT AN EYE WALL REPLACEMENT CYCLE
IS LIKELY, WHICH WILL ALSO CONTRIBUTE TO THE WEAKENING TREND
OVER THE NEXT 24 TO 48 HOURS. 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 80 KTS BY TAU 36 AS IT MOVES INLAND DUE TO THE
FRICTIONAL EFFECTS OF LAND AND VERY HIGH (> 35 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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