WDPN32 PGTW 121500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 15W (BOLAVEN) WARNING NR 
023//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.6N 144.3E
   INITIAL INTENSITY: 155 KTS
   GEOGRAPHIC REFERENCE: 211 NM SOUTHEAST OF IWO TO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 52 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE
SYSTEM HAS SUSTAINED OVERALL CONVECTIVE SIGNATURE AND WRAP AND A
SHARPLY-OUTLINED EYE, SLIGHTLY ENLARGED AT 16NM DIAMETER. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE IN
THE EIR LOOP. THE INITIAL INTENSITY OF 155KTS IS ALSO PLACED WITH
HIGH CONFIDENCE BASED ON THE DVORAK ESTIMATES FROM PGTW AND RJTD AND 
THE HIGH END OF AUTOMATED DVORAK ESTIMATES THAT REFLECTS THE 6-HR 
SUSTAINED STRUCTURE.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.5 - 155 KTS
   RJTD: T7.5 - 155 KTS
   CIMSS ADT: 146 KTS AT 121200Z
   CIMSS D-MINT: 153 KTS AT 121200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: STY BOLAVEN WILL CONTINUE TO ACCELERATE
NORTHEASTWARD ON THE POLEWARD SIDE OF THE STR. THE STRONG
WESTERLIES THAT HAS ENHANCED THE POLEWARD OUTFLOW WILL BECOME MORE
INTENSE AND RAPIDLY INCREASE THE VERTICAL WIND SHEAR. ADDITIONALLY,
ALONG-TRACK SST WILL GRADUALLY COOL. THIS COMBINED EFFECT WILL
RESULT IN A RAPID WEAKENING AND BY TAU 72, THE CYCLONE WILL BE
REDUCED TO 70KTS, POSSIBLY WEAKER. CONCURRENTLY BY TAU 48, 15W
WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) AND BY TAU 72, WILL
TRANSFORM INTO A HURRICANE-FORCE COLD-CORE LOW. 

MODEL DISCUSSION: NUMERICAL MODELS REMAIN IN VERY TIGHT AGREEMENT
WITH AN EVEN AND GRADUAL SPREAD TO A MERE 220NM BY TAU 72, LENDING
HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. THERE IS ONLY MEDIUM
CONFIDENCE IN THE INTENSITY FORECAST GIVEN THE UNCERTAINTIES
ASSOCIATED WITH ETT.

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