Tropical Storm PRAPIROON Advisory Çar, 17.10.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (PRAPIROON)
WARNING NR 38//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 22W (PRAPIROON), LOCATED APPROXIMATELY 215
NM SOUTH-SOUTHEAST OF KADENA AIR BASE, OKINAWA, JAPAN, HAS TRACKED
NORTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED
INFRARED (IR) SATELLITE IMAGERY CONTINUES TO DEPICT WEAKENING
CENTRAL CONVECTION BUT HAS RETAINED EXTENSIVE CONVECTIVE BANDING
AROUND A LARGE TIGHTLY-WRAPPED AND WELL-DEFINED LOW LEVEL
CIRCULATION CENTER (LLCC). THE INITIAL INTENSITY WAS ASSESSED AT 55
KNOTS, WHICH IS SLIGHTLY HIGHER THAN DVORAK CURRENT INTENSITY
ESTIMATES FROM RJTD, KNES AND PGTW, DUE TO THE WELL DEFINED STORM
STRUCTURE SEEN IN A 161859Z AMSU 89 GHZ MICROWAVE IMAGE. UPPER
LEVEL ANALYSIS AND ANIMATED WATER VAPOR IMAGERY REVEAL THE SYSTEM
CONTINUES TO MAINTAIN NEAR RADIAL OUTFLOW AND IS IN AN AREA OF LOW
(05-10 KNOT) VERTICAL WIND SHEAR. THERE IS GOOD CONFIDENCE IN THE
INITIAL POSITION AND CURRENT MOTION BASED UPON THE IR LOOP AND THE
MICROWAVE IMAGE. TS 22W HAS STARTED TO MAKE THE TURN TO THE NORTH
AS SEEN IN THE RECENT NORTHWESTWARD MOTION AS A MID-LATITUDE TROUGH
DIGS IN FROM EASTERN CHINA AND THE SUBTROPICAL RIDGE BECOMES MORE
EAST-WEST ORIENTED.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING BULLETIN.
   B. TS 22W IS FORECAST TO TRACK SLOWLY MORE NORTHWARD IN THE NEXT
12 HOURS, AND BEGIN TO TURN NORTHEASTWARD UNDER THE STEERING
INFLUENCE OF THE STR AND ACCELERATE AS A MIDLATITUDE SHORTWAVE
TROUGH CONTINUES TO DIG IN FROM EASTERN CHINA. DYNAMIC MODEL
GUIDANCE IS IN TIGHT AGREEMENT THROUGH TAU 72 WITH SOME SLIGHT
DISAGREEMENT WITH ALONG TRACK SPEEDS. THE JTWC FORECAST IS
POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS AND IS HIGHLY
CONSISTENT WITH THE PREVIOUS FORECAST. TS 22W IS FORECAST TO
MAINTAIN ITS CURRENT INTENSITY THROUGH TAU 24 DUE TO THE RADIAL
OUTFLOW AND GENERALLY FAVORABLE CONDITIONS. NEAR TAU 48, TS 22W IS
FORECAST TO BEGIN EXTRA-TROPICAL TRANSITION (ETT) AS IT BEGINS TO
INTERACT WITH THE BAROCLINIC ZONE.
   C. IN THE EXTENDED TAUS, TS 22W IS EXPECTED TO COMPLETE ETT BY
TAU 72 AND ACCELERATE NORTHEASTWARD AS IT BECOMES EMBEDDED WITHIN
THE STRONG MIDLATITUDE WESTERLY FLOW. DYNAMIC MODEL GUIDANCE IS IN
GOOD AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE ENTIRE
JTWC FORECAST TRACK.//
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