Tropical Storm BOLAVEN Advisory Sun Aug 26

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (BOLAVEN) WARNING NR 27//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 16W (BOLAVEN), LOCATED APPROXIMATELY 17 NM NORTH-
NORTHEAST OF KADENA AB, JAPAN, HAS TRACKED WEST-NORTHWESTWARD AT 10
KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY
DEPICTS A WELL-ORGANIZED SYSTEM WITH A SMALL 9-NM EYE AND SHOWS
THAT THE SYSTEM IS GOING THROUGH AN EYEWALL REPLACEMENT CYCLE. A
261047Z SSMIS IMAGE DEPICTS A 20 NM DIAMETER EYEWALL SURROUNDED BY
MULTIPLE DEEP CONVECTIVE BANDS WRAPPING INTO THE SYSTEM. THERE IS
HIGH CONFIDENCE IN THE INITIAL POSITION BASED ON THE SMALL EYE
FEATURE AND RADAR FIXES FROM JAPAN. THE INITIAL INTENSITY IS
ASSESSED AT 105 KNOTS BASED ON A DVORAK DATA-T ESTIMATE OF 102 KNOTS
FROM PGTW. THUS FAR, SURFACE OBSERVATIONS ACROSS OKINAWA SHOW 40 TO
50-KNOT SUSTAINED WINDS WITH GUSTS AS HIGH AS 76 KNOTS AND A MINIMUM
SLP OF 952 MB. RADAR IMAGERY SHOWS A 20 NM INNER EYEWALL POSITIONED
OVER CENTRAL OKINAWA BUT NOW BEGINNING TO TRACK NORTHWESTWARD.
ANIMATED WATER VAPOR IMAGERY INDICATES RADIAL OUTFLOW. THE 26/00Z
500MB ANALYSIS INDICATES THAT THE SUBTROPICAL RIDGE (STR) EXTENDS
WESTWARD ACROSS WESTERN JAPAN INTO THE CHEJU-DO REGION WITH A DEEP
MIDLATITUDE SHORTWAVE TROUGH NOW POSITIONED ALONG 120E OVER THE
YELLOW SEA.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY 16W IS TRACKING GENERALLY NORTHWESTWARD ALONG THE SOUTHWEST
PERIPHERY OF THE STR WITH A MINOR TROCHOIDAL MOTION (WOBBLE)
EVIDENT. TY 16W IS EXPECTED TO CONTINUE TRACKING GENERALLY
NORTHWESTWARD THROUGH TAU 12 BUT SHOULD THEN TURN NORTHWARD ALONG
THE WESTERN PERIPHERY OF THE STR AND TRACK INTO THE YELLOW SEA.
DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT WITH A 100 NM SPREAD
WEST OF SEOUL (NEAR TAU 48). THE JTWC FORECAST IS CONSISTENT WITH
THE PREVIOUS WARNINGS AND IS HEDGED EAST OF THE MODEL CONSENSUS. TY
16W IS EXPECTED TO WEAKEN GRADUALLY THROUGH TAU 36. AFTER 36, THE
SYSTEM WILL WEAKEN SIGNIFICANTLY DUE TO COOLER SST AND INCREASING,
STRONG VERTICAL WIND SHEAR. TY 16W IS EXPECTED TO MAKE LANDFALL NEAR
TAU 48 AND WILL ALSO BEGIN EXTRA-TROPICAL TRANSITION (ETT). TY 16W
IS FORECAST TO COMPLETE ETT NEAR TAU 72 AND SHOULD REMAIN A GALE-
FORCE LOW AS IT TRACKS OVER MANCHURIA. BASED ON THE TIGHT DYNAMIC
MODEL GROUPING, THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK.//
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