WDPN32 PGTW 112100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 15W (BOLAVEN)       
WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.7N 142.9E
   INITIAL INTENSITY: 155 KTS
   GEOGRAPHIC REFERENCE: 319 NM SOUTH-SOUTHEAST OF IWO TO
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 58 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
THE CIMSS M-PERC PRODUCT INDICATES AN IMMINENT EYEWALL REPLACEMENT
CYCLE (ERC) WITH ONSET PROBABILITIES PEAKING AT 100 PERCENT AROUND
110000 TO 110300Z. THUS FAR, THERE HAS BEEN NO IMPACT ON THE MAXIMUM
SUSTAINED WINDS, WHICH HAVE REMAINED AT 155 KNOTS. HOWEVER, AN
111624Z AMSR2 91 GHZ COLOR COMPOSITE MICROWAVE IMAGE DOES SHOW A
DEVELOPING OUTER EYEWALL WITH A MOAT FEATURE SURROUNDING AN INTENSE 
35-40 NM DIAMETER INNER EYEWALL AND CORE. ANIMATED ENHANCED INFRARED 
(EIR) SATELLITE IMAGERY DEPICTS A SYMMETRIC CORE WITH A 12 NM ROUND 
EYE, EYE TEMPERATURE OF PLUS 19.4 C, AND EXTENSIVE SPIRAL BANDING. 
THE INITIAL POSITION IS BASED ON THE EIR IMAGERY WITH HIGH 
CONFIDENCE. THE INITIAL INTENSITY REMAINS ASSESSED AT 155 KNOTS BASED 
ON THE CONCORDANT AGENCY DVORAK ESTIMATES AND CIMSS ADT ESTIMATES 
OVER THE PAST SIX HOURS.  

INITIAL WIND RADII BASIS: SAR DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.5 - 155 KTS
   RJTD: T7.5 - 155 KTS
   KNES: T7.5 - 155 KTS
   CIMSS SATCON: 143 KTS AT 111619Z
   CIMSS ADT: 155 KTS AT 111730Z
   CIMSS AIDT: 150 KTS AT 111900Z
   CIMSS DPRINT: 158 KTS AT 111900Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: SUPER TYPHOON (STY) IS TRACKING POLEWARD ALONG
THE WESTERN PERIPHERY OF THE STR, TOWARD A BREAK IN THE STR
ASSOCIATED WITH A DEEP MIDLATITUDE SHORTWAVE TROUGH. THIS TROUGH IS
CLEARLY EVIDENT IN ANIMATED WATER VAPOR IMAGERY AS WELL AS IN THE
RECENT SOUNDINGS FROM THE RYUKYU ISLANDS AND CHICHI-JIMA. STY 15W IS 
FORECAST TO GRADUALLY TURN NORTHEASTWARD THROUGH TAU 36 WITH STEADY 
WEAKENING, INITIALLY RESULTING FROM AN ONGOING ERC EVENT THEN WITH 
INCREASING VERTICAL WIND SHEAR (VWS) AFTER TAU 24. STY BOLAVEN IS 
FORECAST TO WEAKEN RAPIDLY AFTER TAU 36 AS IT BEGINS EXTRA-TROPICAL 
TRANSITION (ETT) AND ACCELERATES NORTHEASTWARD. VWS IS EXPECTED TO 
INCREASE QUICKLY TO HIGH LEVELS (35-40 KNOTS) THEN MORE SUBSTANTIALLY 
(50 KNOTS) NEAR TAU 60 AS THE SYSTEM BECOMES EMBEDDED IN THE 
WESTERLIES NEAR THE JET. STY 15W WILL COMPLETE ETT BY TAU 72 AS IT 
GAINS FRONTAL CHARACTERISTICS AND TRACKS UNDER THE JET WITH VERY HIGH 
(70-80 KNOTS) VWS AND COOL SST (22 C) VALUES. HOWEVER, THE SYSTEM IS 
EXPECTED TO MAINTAIN STORM-FORCE WINDS AS IT TRACKS SOUTH OF THE 
ALEUTIAN ISLANDS AND INTO THE GULF OF ALASKA.   

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN TIGHT
AGREEMENT THROUGH TAU 48 WITH A 80 NM CROSS-TRACK SPREAD IN
SOLUTIONS AT TAU 48. ALTHOUGH RELIABLE INTENSITY GUIDANCE (HAFS-A, 
COAMPS-TC, HWRF) INDICATE STEADY WEAKENING, THERE IS SOME UNCERTAINTY 
IN THE PEAK INTENSITY OVER THE NEXT 12 HOURS WITH POTENTIAL FOR 
SLIGHT INTENSIFICATION TO 160-165 KNOTS BEFORE THE WEAKENING TREND 
COMMENCES. AFTER TAU 48, MODEL GUIDANCE GRADUALLY DIVERGES WITH 
INCREASING UNCERTAINTY IN BOTH THE CROSS-TRACK (200 NM SPREAD AT TAU 
72) AND ALONG-TRACK (330 NM SPREAD AT TAU 72) PORTIONS OF THE JTWC 
FORECAST TRACK. THEREFORE, THERE IS HIGH TRACK CONFIDENCE THROUGH TAU 
48 AND MEDIUM CONFIDENCE AFTER TAU 48 WITH MEDIUM OVERALL CONFIDENCE.   

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