Tropical Storm BAVI Advisory Thu Aug 27

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (BAVI) WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 09W (BAVI), LOCATED APPROXIMATELY 176 NM SOUTHWEST OF
KUNSAN AB, HAS TRACKED NORTHWARD AT 12 KNOTS (KTS) OVER THE PAST SIX
HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS A 30NM
CLOUD-FILLED EYE SURROUNDED BY DEEP CONVECTION. A 260709Z SSMIS 91GHZ
MICROWAVE IMAGE REVEALS DEEP CONVECTIVE BANDING WRAPPING AROUND THE
NORTHERN SEMICIRCLE ALONG WITH A DEFINED MICROWAVE EYE FEATURE. THE
CURRENT INTENSITY IS SET AT 95KTS BASED ON DVORAK CURRENT INTENSITY
ESTIMATES OF T5.0-5.5 (90-102 KTS) BY PGTW AND RJTD. THE CURRENT WIND
RADII HAVE BEEN UPDATED BASED ON A DETAILED ANALYSIS OF A 260202Z ASCAT-
C IMAGE AND RECENT SURFACE OBSERVATIONS. UPPER-LEVEL CONDITIONS ARE
FAVORABLE WITH ROBUST POLEWARD OUTFLOW AND LOW TO MODERATE VERTICAL WIND
SHEAR (VWS). SEA SURFACE TEMPERATURES (SST) OF 29 TO 30 DEGREES CELSIUS
REMAIN CONDUCIVE. A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE EAST
REMAINS THE PRIMARY STEERING MECHANISM AND TY 09W IS TRACKING NORTHWARD
ALONG ITS WESTERN PERIPHERY.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC
REASONING MESSAGE.
   B. OVER THE NEXT 48 HOURS, TY 09W WILL TRACK POLEWARD ALONG THE
WESTERN PERIPHERY OF THE BUILDING STR TO THE EAST. NUMERICAL MODEL
GUIDANCE IS IN EXCELLENT AGREEMENT THROUGH TAU 36 THEN THE MODELS
DIVERGE AS THE SYSTEM UNDERGOES EXTRATROPICAL TRANSITION (ETT). OF NOTE,
THE ECMWF SOLUTION DIVERGES TO THE EAST FROM THE MODEL MAJORITY AFTER
TAU 24. HOWEVER, THE ECMWF ENSEMBLE SOLUTIONS ARE IN GOOD AGREEMENT
REFLECTING A HIGH CONFIDENCE (LOW UNCERTAINTY) FORECAST TRACK. AS THE
SYSTEM TRANSITS POLEWARD, INCREASING VWS AFTER TAU 12 AND COOLING (25-28
CELSIUS) SST IN THE NORTHERN YELLOW SEA WILL WEAKEN THE SYSTEM. LANDFALL
IS EXPECTED PRIOR TO TAU 24 AND WILL CAUSE THE SYSTEM TO WEAKEN MORE
RAPIDLY DUE TO LAND INTERACTION. AROUND TAU 24, TY 09W WILL COMMENCE ETT
AS IT INTERACTS WITH THE MIDLATITUDE SOUTHWESTERLY FLOW AND ETT
COMPLETION IS EXPECTED BY TAU 48. AT THIS POINT, THE SYSTEM WILL GAIN
FRONTAL CHARACTERISTICS AND BE NEAR THE JET. OVERALL, DUE TO THE GOOD
AGREEMENT IN MODEL SOLUTIONS, THERE IS HIGH CONFIDENCE IN THE JTWC
FORECAST TRACK WHICH IS LOCATED NEAR THE MULTI-MODEL CONSENSUS.//
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