Tropical Storm BUALOI Advisory 10月21日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 22W (BUALOI) WARNING NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 22W (BUALOI), LOCATED APPROXIMATELY 218 NM EAST-
SOUTHEAST OF SAIPAN, CNMI, HAS TRACKED NORTHWESTWARD AT 10 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
SHOWS A MID-SIZED SYSTEM WITH COMPACT RAIN BANDS WRAPPING TIGHTLY
INTO A RAGGED AND OBSCURED 10NM EYE. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE, ADJUSTED FOR A SLIGHT
TILT AND LINED UP WITH A SHARPLY-OUTLINED MICROWAVE EYE IN THE
201621Z GPM 37GHZ IMAGE. THE INITIAL INTENSITY OF 75KTS IS BASED ON
CONGRUENT DVORAK ESTIMATES OF T4.5/77KTS FROM PGTW AND RJTD.
UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW (05-
10KT) VERTICAL WIND SHEAR (VWS) AND DUAL OUTFLOW WITH A STRONG
EQUATORWARD BIAS; HOWEVER, A TUTT CELL TO THE NORTHWEST IS CAUSING
SUBSIDENCE AND STIFLING SOME OF THE POLEWARD OUTFLOW. ALONG-TRACK SST
VALUES AT 30C REMAIN CONDUCIVE. TS 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. TS 22W WILL CONTINUE ON ITS CURRENT TRACK THROUGH TAU 48 BEFORE
TURNING MORE NORTHWARD AS IT APPROACHES THE STR AXIS AND GRADUALLY
INTENSIFY TO 85KTS BY TAU 12 AS IT APPROACHES THE NORTHERN MARIANA
ISLANDS THEN PEAK TO 115KTS BY TAU 72, FUELED BY THE AFOREMENTIONED
FAVORABLE DYNAMICS.
   C. AFTER TAU 72, TS 22W WILL ACCELERATE NORTH-NORTHEASTWARD AFTER
IT CRESTS THE STR, MAINTAINING A PEAK OF 115KTS UP TO TAU 96 BEFORE
IT STARTS WEAKENING MOSTLY DUE TO INCREASING VWS. CONCURRENTLY AT TAU
96, THE SYSTEM WILL BEGIN EXTRA-TROPICAL TRANSITION AND BY TAU 120
WILL BE REDUCED TO 90KTS WITH AN EXPANDING WIND FIELD COALESCING WITH
THE BAROCLINIC WIND FLOW. NUMERICAL MODELS REMAIN IN TIGHT AGREEMENT
WITH MINIMAL SPREADING TO 115NM AT TAU 72 AND WIDER BUT GRADUAL AND
EVEN SPREADING TO 300NM AT TAU 120, LENDING HIGH CONFIDENCE IN THE
JTWC FORECAST TRACK.//
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