Tropical Storm MAYSAK Advisory 9月2日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (MAYSAK) WARNING
NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 10W (MAYSAK), LOCATED APPROXIMATELY 184 NM NORTH-
NORTHWEST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD
AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS AN INTENSE SYSTEM THAT IS NOW BEGINNING TO
WEAKEN AS EVIDENCED BY AN ENLARGED, RAGGED, AND ELONGATED 40-NM EYE.
THE EIR LOOP ALSO INDICATES THAT THE CYCLONE HAS UNDERGONE AN EYEWALL
REPLACEMENT CYCLE (ERC). THIS IS ALSO CAPTURED IN THE 1707Z AMSR2 89GHZ
MICROWAVE IMAGE THAT SHOWS THE WEAK, FRAGMENTED INNER EYEWALL
SURROUNDED BY THE LARGER OUTER EYEWALL. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED ON THE ABOVE EYE FEATURES THAT LINED UP WELL
WITH A DEFINED CIRCULATION CENTER IN A COMPOSITE RADAR LOOP FROM JMA.
THE INITIAL INTENSITY OF 115 KTS IS BASED ON THE LOW END OF MULTI-
AGENCY DVORAK ESTIMATES OF T6.0/115KTS TO T6.5/127KTS AND REFLECTS THE
WEAKENED STATE. STRONG RADIAL OUTFLOW ALOFT AND WARM SSTS (29-30C)
REMAIN. VWS AT 15-20 KTS HAS INCREASED BUT IS MITIGATED BY THE STORM
MOTION THAT IS IN-PHASE WITH THE UPPER LEVEL WIND FLOW. THE WEAKENING,
FOR NOW, IS DUE TO THE ERC. TY MAYSAK IS TRACKING UNDER THE COMBINED
STEERING INFLUENCE OF TWO SUBTROPICAL RIDGES (STR) AND IS CURRENTLY
ROUNDING THE EDGE OF THE PRIMARY STEERING RIDGE 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. HOWEVER, IT WILL STILL BE A STRONG TYPHOON AT 95 KTS
PRIOR TO LANDFALL AT TAU 18 JUST WEST OF BUSAN. AFTERWARD, THE SYSTEM
WILL RAPIDLY ERODE WITH THE ADDITION OF LAND INTERACTION WITH THE
RUGGED MOUNTAIN RANGES OF THE KOREAN PENINSULA. CONCURRENTLY AT TAU 24,
THE SYSTEM WILL BEGIN EXTRATROPICAL TRANSITION (ETT) AS IT BECOMES
EMBEDDED IN THE BAROCLINIC ZONE BECOMING A COLD CORE LOW BY TAU 36.
THERE IS A DISTINCT POSSIBILITY OF DISSIPATION OVER THE RUGGED TAEBAEK
MOUNTAIN RANGES PRIOR TO TAU 48. NUMERICAL MODEL SOLUTIONS REMAIN IN
TIGHT AGREEMENT, WITH THE JTWC FORECAST TRACK PLACED JUST LEFT OF THE
MULTI-MODEL CONSENSUS TO OFFSET THE NAVGEM TRACK, WHICH IS THE SOLE
OUTLIER ON THE RIGHT MARGIN OF THE MODEL ENVELOPE. THERE IS OVERALL
HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.//
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