Tropical Storm LAN Advisory 21 Οκτ.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 25W (LAN) WARNING NR 22//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 25W (LAN), LOCATED APPROXIMATELY 383 NM SOUTH-
SOUTHEAST OF KADENA AB, HAS TRACKED NORTHEASTWARD AT 06 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY DEPICTS A RAPIDLY CONSOLIDATING SYSTEM WITH A 50NM ROUND
EYE, WHICH PROVIDES GOOD CONFIDENCE IN THE INITIAL POSITION. STY 25W
HAS RAPIDLY INTENSIFIED (RI) OVER THE PAST 24 HOURS FROM 75 KNOTS TO
130 KNOTS (55 KNOTS). UPPER-LEVEL ANALYSIS INDICATES EXCELLENT
OUTFLOW, PARTICULARLY POLEWARD, WHICH IS TAPPING INTO THE
MIDLATITUDE WESTERLIES OVER JAPAN. A 201838Z NOAA-19 89GHZ IMAGE
INDICATES A SYMMETRIC EYEWALL WITH FRAGMENTED SPIRAL BANDING. THE
INITIAL INTENSITY IS ASSESSED AT 130 KNOTS BASED ON DVORAK INTENSITY
ESTIMATES RANGING FROM T6.0 (115 KNOTS) TO T7.0 (140 KNOTS). STY 25W
IS TRACKING POLEWARD ALONG THE WESTERN PERIPHERY OF THE DEEP LAYERED
SUBTROPICAL RIDGE.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE. HOWEVER, PEAK INTENSITY IS NOW SET AT
140 KNOTS BASED ON THE ONGOING RI PHASE. ADDITIONALLY, INITIAL WIND
RADII HAVE BEEN ADJUSTED BASED ON A DETAILED ANALYSIS OF A RECENT
ASCAT IMAGE, WHICH SHOWS UNUSUALLY EXTENSIVE GALE-FORCE WINDS.
   B. EIR IMAGERY INDICATES SOME EYE WOBBLE, HOWEVER, STY 25W IS
TRACKING GENERALLY POLEWARD TOWARD CENTRAL JAPAN. STY LAN SHOULD
PEAK WITHIN THE NEXT 12 HOURS THEN WEAKEN AS IT APPROACHES JAPAN AND
BEGINS TO INTERACT WITH THE BAROCLINIC ZONE BY TAU 24. AFTER TAU 24,
STY 25W WILL ENCOUNTER STRONG VERTICAL WIND SHEAR, BEGIN TO INTERACT
WITH LAND AND WILL WEAKEN SIGNIFICANTLY. THE SYSTEM WILL COMPLETE
EXTRA-TROPICAL TRANSITION BY TAU 48 AS IT GAINS FRONTAL
CHARACTERISTICS AND BEGINS TO ACCELERATE NORTHEASTWARD. STY 25W IS
FORECAST TO MAINTAIN EXTENSIVE GALE-FORCE WINDS DUE TO THE VERY
LARGE SIZE OF THE SYSTEM, AND PROXIMITY OF COLD-SURGE WINDS AND
GRADIENT WINDS ASSOCIATED WITH THE FRONTAL ZONE CURRENTLY SITUATED
OVER JAPAN. DYNAMIC MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT,
THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.//
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