WDPN32 PGTW 050300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
RMKS/
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 30W (KONG-REY) WARNING 
NR 29//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 30W (KONG-REY), LOCATED APPROXIMATELY 367 NM
SOUTHWEST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED
NORTH-NORTHWESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTI-SPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TIGHTLY CURVED BANDING
WRAPPING INTO A DEFINED LOW LEVEL CIRCULATION CENTER, WITH AN
EXPANSIVE CLOUD SHIELD ADVANCING OUT WELL AHEAD OF THE CENTER. A
042301Z GMI 89GHZ PASS INDICATES REMAINING CORE CONVECTION HAS
SHALLOWED SIGNIFICANTLY, WITH DEEP CONVECTION CONSOLIDATING ALONG THE
NORTHWESTERN PERIPHERY OF THE SYSTEM AS IT BEGINS TO INTERACT WITH
THE MID-LATITUDE BAROCLINIC ZONE. THE INITIAL POSITION IS PLACED WITH
HIGH CONFIDENCE BASED ON THE DEFINED CENTER REVEALED IN THE 36 GHZ
CHANNEL OF THE AFOREMENTIONED GMI PASS. THIS CENTER IS SLIGHTLY
NORTHWEST OF THE MSI-BASED FIXES, INDICATING SOME TILT IN THE VORTEX.
THE INITIAL INTENSITY IS ASSESSED AT 55 KNOTS BASED ON DVORAK CURRENT
INTENSITY ESTIMATES OF T3.5 (55 KNOTS) FROM PGTW AND RJTD, AS WELL AS
A 51 KNOT SATCON ESTIMATE. UPPER LEVEL ANALYSIS INDICATES THE LLCC IS
STILL IN AN AREA WITH LOW (10-15 KNOT) VERTICAL WIND SHEAR (VWS),
ALTHOUGH THERE IS A SHARP GRADIENT AHEAD OF THE SYSTEM. RADIAL
OUTFLOW REMAINS ROBUST, PARTICULARLY IN THE POLEWARD CHANNEL WHICH IS
GREATLY ENHANCED BY AN APPROACHING MID-LATITUDE TROUGH TO THE
NORTHWEST. SEA SURFACE TEMPERATURES ARE DOWN TO 27 DEGREES CELSIUS
AND DROPPING SHARPLY ALONG THE FORECAST TRACK DUE TO UPWELLING CAUSED
BY THE RECENT PASSING OF TC 28W (TRAMI). THE CYCLONE IS TRACKING
ALONG THE WESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR)
TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 30W WILL CREST THE STR AXIS OVER THE NEXT SIX HOURS AND
BEGIN ACCELERATING NORTHEASTWARD AHEAD OF THE APPROACHING
MID-LATITUDE TROUGH. BY TAU 24, TS 30W WILL BEGIN EXTRATROPICAL
TRANSITION (ETT) AS IT ENCOUNTERS MUCH COOLER WATERS IN THE SEA OF
JAPAN (SOJ). ETT IS EXPECTED TO BE COMPLETED BY TAU 48, AND MAY OCCUR
AS EARLY AS TAU 36.  DESPITE INCREASING WIND SHEAR VALUES, BAROCLINIC
INTERACTION DURING THE ETT MAY ALLOW KONG-REY TO DEVELOP INTO A 40
KNOT COLD-CORE LOW. THE JTWC TRACK FORECAST IS PLACED VERY CLOSE TO
THE PRIOR FORECAST TRACK, WHICH IS IN GOOD AGREEMENT WITH THE
MULTI-MODEL CONSENSUS. DESPITE VARIATIONS IN ALONG-TRACK SPEED,
OVERALL MODEL SPREAD IS LOW, LENDING HIGH CONFIDENCE TO THE JTWC
FORECAST TRACK.//
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