Tropical Storm BAVI Advisory di, 25-08

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (BAVI) WARNING NR
015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 09W (BAVI), LOCATED APPROXIMATELY 197 NM NORTHWEST
OF KADENA AB, OKINAWA, HAS TRACKED NORTH-NORTHWESTWARD AT 07 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS A 15NM RAGGED CLOUD-FILLED EYE WITH SPIRAL BANDING OVER THE
SOUTHERN SEMICIRCLE. A 242231Z SSMIS 91GHZ MICROWAVE IMAGE DEPICTS A
COMPACT EYEWALL SURROUNDING A MICROWAVE EYE FEATURE, WHICH SUPPORTS
THE INITIAL POSITION AND RECENT STORM MOTION WITH HIGH CONFIDENCE.
THE INITIAL INTENSITY REMAINS ASSESSED AT 90 KNOTS BASED ON PGTW,
RJTD, AND KNES DVORAK ESTIMATES OF T5.0 (90 KNOTS). ENVIRONMENTAL
CONDITIONS REMAIN FAVORABLE WITH LOW TO MODERATE (15-20 KNOTS)
NORTHEASTERLY VERTICAL WIND SHEAR (VWS) OFFSET BY ROBUST EQUATORWARD
OUTFLOW, IMPROVING POLEWARD OUTFLOW AND WARM (30C) SST. TY 09W IS
TRACKING POLEWARD ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL
RIDGE (STR) POSITIONED TO THE EAST AND NORTHEAST.
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 72
HOURS ALONG THE WESTERN PERIPHERY OF THE BUILDING STR TO THE EAST.
NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT THROUGH TAU 48 WITH A
72NM SPREAD IN SOLUTIONS AT TAU 48. ADDITIONALLY, THE ECMWF ENSEMBLE
SOLUTIONS ARE ALSO IN GOOD AGREEMENT REFLECTING A HIGH CONFIDENCE
(LOW UNCERTAINTY) FORECAST TRACK. AFTER TAU 48, THE DYNAMIC MODEL
SOLUTIONS DIVERGE AS THE SYSTEM UNDERGOES EXTRA-TROPICAL TRANSITION
AND TRACKS INTO NORTHEAST CHINA. THERE IS SIGNIFICANT UNCERTAINTY,
HOWEVER, IN THE JTWC INTENSITY FORECAST. ENVIRONMENTAL CONDITIONS
ARE EXPECTED TO IMPROVE WITHIN THE NEXT 12 TO 24 HOURS WITH
DECREASING VWS AND IMPROVED OUTFLOW INTO A MIDLATITUDE SHORTWAVE
TROUGH. THEREFORE, THE SYSTEM IS EXPECTED TO PEAK AT 110 KNOTS AT
TAU 24 THEN GRADUALLY WEAKEN AS THE SYSTEM ENCOUNTERS COOLER SST (28-
25C) OVER THE NORTHERN YELLOW SEA AND STRONG VWS AFTER TAU 36. TY
09W SHOULD COMPLETE EXTRA-TROPICAL TRANSITION BY TAU 72 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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