Tropical Storm BAVI Advisory Sun Aug 23

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (BAVI) WARNING NR
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 09W (BAVI), LOCATED APPROXIMATELY 282 NM WEST-
SOUTHWEST OF KADENA AB, OKINAWA, HAS TRACKED NORTH-NORTHEASTWARD AT
09 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A WELL ORGANIZED, COMPACT SYSTEM WITH SUSTAINED
CONVECTION AND FORMATIVE BANDING WRAPPING INTO THE CENTER OF A
CONSOLIDATING LOW LEVEL CIRCULATION. THE INITIAL POSITION IS PLACED WITH
FAIR CONFIDENCE BASED ON THE CIRCULATION EVIDENT IN THE COMPOSITE RADAR
AND MSI LOOPS. THE INITIAL INTENSITY OF 45 KTS IS PLACED WITH HIGH
CONFIDENCE AND IS HEDGED SLIGHTLY HIGHER THAN MULTIAGENCY DVORAK CURRENT
INTENSITY ESTIMATES OF T2.0 (RCTP, 30 KTS) AND T2.5 (PGTW AND RJTD, 35 KTS)
BASED ON OBSERVATIONS FROM ISHIGAKI JIMA OF 45 KTS (10 MINUTE AVERAGE) AND
A 220526Z SATELLITE CONSENSUS INTENSITY ESTIMATE OF 42 KTS. THE SYSTEM IS
TRACKING GENERALLY NORTH-NORTHEASTWARD ALONG AN EXTENSION OF A SUBTROPICAL
RIDGE (STR) POSITIONED TO THE SOUTHEAST AND THROUGH AN ENVIRONMENT FAVORABLE
FOR RAPID INTENSIFICATION WITH VERY WARM (30-31 CELSIUS) SEA SURFACE
TEMPERATURES, LOW (5-10 KTS) VERTICAL WIND SHEAR AND WELL ESTABLISHED
EQUATORWARD OUTFLOW IN THE UPPER LEVELS.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS BAVI WILL CONTINUE TO TRACK GENERALLY NORTHEASTWARD AS IT ROUNDS
THE STR POSITIONED TO THE SOUTHEAST. AN UPPER LEVEL TROUGH POSITIONED TO
THE NORTH IS EXPECTED TO INTERACT WITH THE SYSTEM THROUGH THE NEXT 24 HOURS
AND ENHANCE UPPER LEVEL POLEWARD OUTFLOW. THIS ENHANCED OUTFLOW, ALONG WITH
CONTINUED LOW VERTICAL WIND SHEAR AND VERY WARM SSTS WILL ALLOW FOR FURTHER,
AND POSSIBLY RAPID, INTENSIFICATION TO 70 KTS BY TAU 24 AND TO 80 KTS BY TAU
36. DURING THIS TIME, THE INCOMING SHORTWAVE TROUGH WILL CAUSE A REORIENTATION
AND EROSION OF THE STEERING STR. AS A RESULT, TS BAVI WILL SLOW AND BEGIN
TRACKING NORTHWARD ALONG THE WESTERN PERIPHERY OF A STR POSITIONED TO THE EAST
STARTING AT TAU 48. CONTINUED WARM SSTS AND MODERATE (20-25 KTS) VWS WILL LEAD
TO FURTHER INTENSIFICATION DURING THIS NORTHWARD TRACK AND ALLOW THE SYSTEM TO
REACH 100 KTS BY TAU 72. THERE IS A FAIR DEGREE OF UNCERTAINTY IN MODEL
SOLUTIONS DURING THIS PERIOD DUE TO THE TIMING OF THE INCOMING SHORTWAVE TROUGH,
WITH A 132 NM SPREAD IN ACROSS TRACK SOLUTIONS BY TAU 48. THIS SPREAD IN
SOLUTIONS LENDS ONLY FAIR CONFIDENCE TO THE INITIAL PORTION (TAU 0-72) OF THE
JTWC FORECAST TRACK.
   C. IN THE EXTENDED FORECAST, TS BAVI WILL CONTINUE TO TRACK ALONG THE WESTERN
PERIPHERY OF THE STEERING RIDGE WHICH WILL CONTINUE TO BUILD OVER HONSHU AFTER
THE UPPER LEVEL SHORTWAVE TROUGH PROPAGATES EASTWARD. THE CONTINUED FAVORABLE
ENVIRONMENT OF WARM SSTS AND LOW VWS WILL ALLOW THE SYSTEM TO FURTHER INTENSIFY
TO A PEAK INTENSITY OF 105 KTS BY TAU 96. AS THE SYSTEM CONTINUES TO TRACK ALONG
THE STEERING RIDGE, IT WILL MAKE LANDFALL OVER SOUTH KOREA AFTER TAU 96 AND BEGIN
TO WEAKEN DUE TO THE FRICTIONAL EFFECTS OF LAND INTERACTION. GLOBAL MODEL
SOLUTIONS REMAIN IN FAIR AGREEMENT WITH A 233 NM ACROSS TRACK SPREAD AT TAU 120.
THIS SPREAD IN MODEL SOLUTIONS LENDS OVERALL FAIR CONFIDENCE IN THE JTWC FORECAST
TRACK.//
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