Tropical Storm BAVI Advisory Wed Aug 26

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (BAVI) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 09W (BAVI), LOCATED APPROXIMATELY 169 NM EAST-
NORTHEAST OF SHANGHAI, CHINA, HAS TRACKED NORTH-NORTHWESTWARD AT 11
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS GRADUAL WEAKENING AND WARMING OF CLOUD TOP
TEMPERATURES, HOWEVER, THE SYSTEM HAS RETAINED A 20NM EYE. A 252217Z
SSMIS 91GHZ MICROWAVE IMAGE REVEALS AN ERODING INNER EYEWALL WITH A
NARROW MOAT AND OUTER EYEWALL. THE UW-CIMSS M-PERC PRODUCT DEPICTED
THE WEAK ERC AND SHOWED A PEAK PROBABILITY OF 45%. UPPER-
LEVEL CONDITIONS ARE FAVORABLE WITH ROBUST POLEWARD OUTFLOW AND LOW
TO MODERATE VERTICAL WIND SHEAR (VWS). SST VALUES (29 TO 30C) REMAIN
CONDUCIVE. THE INITIAL INTENSITY IS ASSESSED AT 100 KNOTS BASED ON
DVORAK CURRENT INTENSITY ESTIMATES OF 5.0-5.5 (90-102 KNOTS) AND A
252340Z ADT ESTIMATE OF 5.3/5.4 (ROUGHLY 100 KNOTS). TY 09W IS
TRACKING POLEWARD ALONG THE WESTERN PERIPHERY OF A DEEP-LAYERED
SUBTROPICAL RIDGE (STR) POSITIONED TO THE EAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY 09W WILL CONTINUE TO TRACK POLEWARD OVER THE NEXT 48
HOURS ALONG THE WESTERN PERIPHERY OF THE BUILDING STR TO THE EAST.
WITH THE EXCEPTION OF THE SOLE OUTLIER AFUI, NUMERICAL MODEL
GUIDANCE IS IN TIGHT AGREEMENT THROUGH TAU 24 WITH A 31NM SPREAD IN
SOLUTIONS AT TAU 24. ADDITIONALLY, THE ECMWF ENSEMBLE SOLUTIONS ARE
ALSO IN GOOD AGREEMENT REFLECTING A HIGH CONFIDENCE (LOW
UNCERTAINTY) FORECAST TRACK. NEAR TAU 24, THE SYSTEM WILL BEGIN
EXTRA-TROPICAL TRANSITION AS IT INTERACTS THE MIDLATITUDE
SOUTHWESTERLY FLOW. TY 09W WILL GRADUALLY WEAKEN AS THE SYSTEM
ENCOUNTERS COOLER SST (28-25C) OVER THE NORTHERN YELLOW SEA AND
STRONG VWS AFTER TAU 12. TY 09W SHOULD COMPLETE EXTRA-TROPICAL
TRANSITION BY TAU 48 AS IT GAINS FRONTAL CHARACTERISTICS AND NEARS
THE JET. OVERALL, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST
TRACK WHICH IS POSITIONED NEAR THE MULTI-MODEL CONSENSUS.//
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