Tropical Storm BUALOI Advisory Seg, 21-10

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 22W (BUALOI) WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 22W (BUALOI), LOCATED APPROXIMATELY 154 NM EAST-
SOUTHEAST OF SAIPAN, CNMI, HAS TRACKED NORTHWESTWARD AT 11 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS A
MID-SIZED SYSTEM WITH COMPACT RAIN BANDS WRAPPING TIGHTLY INTO A
SYMMETRIC 10NM EYE. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE EYE FEATURE, ADJUSTED FOR A SLIGHT TILT. THE
INITIAL INTENSITY OF 85KTS IS BASED ON THE HIGH END OF AGENCY DVORAK
ESTIMATES RANGING FROM T4.5/77KTS TO T5.0/90KTS AND REFLECTS THE
IMPROVED STATE. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE
ENVIRONMENT WITH LOW (05-10KT) VERTICAL WIND SHEAR (VWS) AND DUAL
OUTFLOW - EASTWARD AND EQUATORWARD; HOWEVER, A TUTT CELL TO THE
NORTHWEST IS CAUSING SUBSIDENCE AND STIFLING THE POLEWARD OUTFLOW.
ALONG-TRACK SST VALUES AT 30C REMAIN CONDUCIVE. TY 22W IS TRACKING
ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE
(STR) TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 22W WILL CONTINUE ON ITS CURRENT TRACK THROUGH TAU 48 BEFORE
TURNING MORE NORTHWARD AS IT APPROACHES THE STR AXIS. FUELED BY THE
AFOREMENTIONED OVERALL FAVORABLE DYNAMICS THE SYSTEM WILL GRADUALLY
INTENSIFY TO 95KTS BY TAU 12 AS IT TRACKS OVER THE NORTHERN MARIANA
ISLANDS THEN PEAK TO 120KTS BY TAU 72 NEAR IWO TO, JAPAN.
   C. AFTER TAU 72, TY 22W WILL ACCELERATE NORTH-NORTHEASTWARD AFTER
IT CRESTS THE STR AND GRADUALLY THEN RAPIDLY DECAY MOSTLY DUE TO
INCREASING VWS AND COOLING SSTS. CONCURRENTLY AT TAU 96, THE SYSTEM
WILL BEGIN EXTRA-TROPICAL TRANSITION AND BY TAU 120 WILL TRANSFORM
INTO AN 80KT COLD CORE LOW WITH AN EXPANDING WIND FIELD COALESCING
WITH THE
BAROCLINIC WIND FLOW. NUMERICAL MODELS REMAIN IN TIGHT AGREEMENT
WITH MINIMAL SPREADING TO 135NM AT TAU 72 AND WIDER BUT GRADUAL AND
EVEN SPREADING TO 190NM AT TAU 120, LENDING HIGH CONFIDENCE IN THE
JTWC FORECAST TRACK.//
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