WDPN32 PGTW 312100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 23W (KONG-REY) WARNING NR 
028//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.2N 120.1E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 691 NM SOUTHWEST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 35 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A RAGGED 
AND ELONGATED CORE OF THE TROPICAL STORM 23W AS IT TRACKS NORTHWARD
AFTER RE-EMERGING OVER THE COOL (24-25 CELSIUS) WATERS OF TAIWAN
STRAIT. MOST OF THE CENTRAL CONVECTION IS DEPLETED WITH THE REMNANT 
DEEP CONVECTION LIMITED TO THE EASTERN SEMICIRCLE, AS THE MAIN FEEDER 
BANDS SQUEEZE BETWEEN THE RAGGED CENTRAL MOUNTAIN RANGE OF TAIWAN AND 
THE TIGHTER PRESSURE GRADIENT TO THE WEST. HOWEVER, POLEWARD OUTFLOW 
REMAINS STRONG, AS THE SYSTEM ROUNDS THE AXIS OF A SUBTROPICAL RIDGE 
TO THE EAST AND APPROACHES THE BAROCLINIC ZONE TO THE NORTH. THE 
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE 
ANIMATED EIR AND ON A BROAD LOW-LEVEL CIRCULATION ON A COMPOSITE RADAR 
LOOP FROM THE TAIWAN CENTRAL WEATHER BUREAU. THE INITIAL INTENSITY OF 
60 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A BLEND OF DVORAK 
FIXES, OBJECTIVE ESTIMATES LISTED BELOW, AS WELL AS THE 311330Z ASCAT-
C PASS EXTRAPOLATION AND REFLECTS THE SIGNIFICANT 6-HR DEGRADATION ON 
THE EIR LOOP.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO
THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T5.0 - 90 KTS
   DEMS: T4.5 - 77 KTS
   CIMSS SATCON: 70 KTS AT 311724Z
   CIMSS ADT: 87 KTS AT 311730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 24-25 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: WIND FIELD INTERACTION WITH TERRAIN ON BOTH SIDE
OF THE TAIWAN STRAIT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TS 23W IS FORECAST TO START TRACKING 
NORTHWESTWARD, ALONG THE PERIPHERY OF THE STR TO THE EAST. THE
PROXIMITY TO LAND, COOLING SEA SURFACE TEMPERATURES AND INCREASING
VERTICAL WIND SHEAR WILL CAUSE THE SYSTEM TO CONTINUE WEAKENING. 
APPROXIMATELY BY TAU 24, TROPICAL STORM 23W WILL BEGIN
EXTRATROPICAL TRANSITION AS IT ENTERS THE BAROCLINIC ZONE AND
INTERACTS WITH THE WESTERLY FLOW. BY THAT TIME THE VERTICAL WIND
SHEAR WILL EXCEED 35 KTS AND CONTINUE INCREASES, WHILE THE SYSTEM
TRACKS ALONG THE NORTHWESTERN PERIPHERY OF THE STR. TS 23W IS
EXPECTED TO COMPLETE THE EXTRATROPICAL TRANSITION BY TAU 36. AFTER
THAT, WHILE AT TROPICAL DEPRESSION INTENSITY, IT WILL GET EMBEDDED
WITH THE UPPER-LEVEL JET FLOW AND RAPIDLY ACCELERATE EASTWARD.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT IN
REGARD TO THE TRACK THROUGHOUT THE FORECAST, WITH 130NM CROSS-TRACK
SPREAD AT TAU 48, AS THE SYSTEM BECOMES AN EXTRATROPICAL COLD-CORE
LOW. JTWC FORECAST IS LAID ON THE SOUTHERN SIDE OF THE MULTI-MODEL
CONSENSUS, LEANING CLOSER TO THE GFS TRACKER, THAN MORE NORTHERLY
NAVGEM AND UKMET. JTWC INTENSITY GUIDANCE IS ALSO IN CLOSE
AGREEMENT WITH THE MULTI-MODEL CONSENSUS, AS ALL MEMBERS PREDICTS A
STEADY WEAKENING TREND THROUGHOUT THE FORECAST PERIOD.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM//
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