WDPN32 PGTW 292100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 23W (KONG-REY) WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.8N 125.5E
   INITIAL INTENSITY: 125 KTS
   GEOGRAPHIC REFERENCE: 439 NM SOUTH-SOUTHEAST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 46 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON
23W (KONG-REY) WITH A LARGE, 55 NM EYE AND A SYMMETRIC CENTRAL
DENSE OVERCAST COVERING THE EYEWALL. THE EIR IMAGERY ALSO DEPICTS
VERY COLD CLOUD TOPS (-80 C) BEGINNING TO ENCIRCLE THE EYEWALL,
SUGGESTING EVEN FURTHER STRENGTHENING. ENVIRONMENTAL ANALYSIS
INDICATES THAT 23W REMAINS IN A HIGHLY FAVORABLE ENVIRONMENT
CHARACTERIZED BY ROBUST RADIAL OUTFLOW ALOFT, LOW (10-15 KTS)
VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA SURFACE TEMPERATURES.
THE MAIN INHIBITOR FOR ANY FURTHER DEVELOPMENT IS THE LARGE EYE.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
EYE IN THE ANIMATED EIR SATELLITE IMAGERY. THE INITIAL INTENSITY
OF 125 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY
DVORAK AND OBJECTIVE INTENSITY ESTIMATES LISTED BELOW. THE INTENSITY 
IS HEDGED SLIGHTLY BELOW WHAT SOME OF THE OBJECTIVE ESTIMATES SUGGEST 
DUE TO THE LARGE EYE.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED TO THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   RJTD: T5.5 - 102 KTS
   RCTP: T6.5 - 127 KTS
   KNES: T6.5 - 127 KTS
   CIMSS SATCON: 131 KTS AT 291711Z
   CIMSS ADT: 129 KTS AT 291800Z
   CIMSS AIDT: 130 KTS AT 291800Z
   CIMSS DPRINT: 130 KTS AT 291800Z
   CIMSS DMINT: 133 KTS AT 291711Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: 23W IS FORECAST TO CONTINUE TRACKING
NORTHWESTWARD, ALONG THE WESTERN PERIPHERY OF THE STR POSITIONED TO
THE EAST THROUGH TAU 36. NEAR TAU 36, 23W IS EXPECTED TO MAKE
LANDFALL ALONG THE SOUTHEASTERN COAST OF TAIWAN. NEAR TAU 48, THE
SYSTEM IS FORECAST TO EMERGE WITHIN THE TAIWAN STRAIT AS IT BEGINS
TO ROUND THE AXIS OF THE STR. AFTER TAU 48, 23W WILL BEGIN TRACKING
NORTHEASTWARD FOR THE REMAINDER OF THE FORECAST PERIOD WITH
EXTRATROPICAL TRANSITION BEGINNING AT TAU 72 AND COMPLETE BY TAU
96, NEAR KYUSHU. REGARDING INTENSITY, 23W IS EXPECTED TO CONTINUE
INTENSIFYING TO AROUND 135 KTS AT TAU 12, AND WILL MAINTAIN THAT
INTENSITY THROUGH TAU 24. HOWEVER, IF THE EYE BEGINS TO SHRINK,
PEAK INTENSITY COULD RISE EVEN HIGHER. NONETHELESS, AFTER TAU 24,
SHEAR IS ANTICIPATED TO RISE ABOVE 20 KTS AND SEA SURFACE
TEMPERATURES WILL SLOWLY DROP AT THE STORM APPROACHES TAIWAN. AN
INTENSITY OF 110-115 KTS IS FORECAST NEAR THE TIME OF LANDFALL.
AFTER THE SYSTEM PASSES OVER TAIWAN AN INTENSITY OF AROUND 75 KTS
IS FORECAST AFTER TERRAIN INTERACTION HAS TAKEN ITS TOLL ON THE
VORTEX. NEAR TAU 72, VERTICAL WINDS SHEAR WILL BEGIN TO QUICKLY
RISE AND SEA SURFACE TEMPERATURES WILL DROP, CAUSING RAPID
WEAKENING. BY TAU 96, 23W WILL TRANSITION INTO AN EXTRATROPICAL
CYCLONE WITH AROUND 40 KNOT WINDS AS IT APPROACHES KYUSHU.   

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS GOOD AGREEMENT
CONCERNING THE TRACK OF 23W THROUGH TAU 72 WITH A 120 NM CROSS
TRACK SPREAD AT THAT TIME. CROSS-TRACK SPREAD NEAR THE TIME OF
LANDFALL IS ABOUT 67 NM. THE MAIN OUTLIER REGARDING TRACK IS HWRF,
WHICH TRACKS THE SYSTEM SOUTH OF TAIWAN. AFTER TAU 72, ALONG-TRACK
SPREAD INCREASES DUE TO DIFFERENCES IN THE INTERACTION WITH THE JET
AND INTERACTION WILL EASTERN CHINA. AS A RESULT, THE JTWC TRACK
FORECAST IS PLACED CLOSE TO CONSENSUS WITH HIGH CONFIDENCE THROUGH
TAU 72 AND MEDIUM THEREAFTER. INTENSITY GUIDANCE IS IN MODERATE
AGREEMENT WITH WEAKENING AFTER TAU 24 AND A MORE GRADUAL WEAKENING
AFTER TAU 48. THE MESOSCALE MODELS HAVE PEAK INTENSITIES RANGE FROM
115-135 KTS AT TAU 12. GFS DIFFERS GREATLY SUGGESTING A MUCH LOWER
INTENSITY. THE JTWC INTENSITY FORECAST IS PLACED ON THE HIGHER END
OF THE MESOSCALE MODELS DUE TO THE VERY COLD CLOUD TOPS, WARM EYE
TEMPERATURE, AND EXTREMELY GOOD OUTFLOW MECHANISMS WITH OVERALL
MEDIUM CONFIDENCE. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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