WDPN32 PGTW 130600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (BOLAVEN) WARNING NR 026//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.2N 148.7E
   INITIAL INTENSITY: 115 KTS
   GEOGRAPHIC REFERENCE: 670 NM SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 23 KTS
   SIGNIFICANT WAVE HEIGHT: 48 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE
SYSTEM CONTINUED TO SIGNIFICANTLY ERODE AND ELONGATE AS IT
ACCELERATED NORTHEASTWARD ON THE POLEWARD SIDE OF THE STEERING
RIDGE DEEPER INTO THE STRONG PREVAILING WESTERLIES. A TRACE OF A RECENTLY OBSCURED EYE IS STILL EVIDENT. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE REMNANT EYE IN THE EIR LOOP. THE INITIAL INTENSITY OF 115KTS IS ALSO PLACED WITH HIGH CONFIDENCE
BASED ON THE HIGH END OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND
REFLECTS THE 6-HR DETERIORATION. ANALYSIS INDICATES A HIGHLY
UNFAVORABLE ENVIRONMENT WITH THE STRONG POLEWARD OUTFLOW OFFSET BY
INCREASING VWS, COOLING SST, AND DRY AIR INTRUSION AT THE LOWER
LEVELS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

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


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   KNES: T6.5 - 127 KTS
   CIMSS SATCON: 108 KTS AT 130340Z
   CIMSS ADT: 97 KTS AT 130220Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 20-25 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: COLD DRY AIR INTRUSION FROM THE NORTHWEST THROUGH
WEST. 

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: TY BOLAVEN WILL CONTINUE TO ACCELERATE
NORTHEASTWARD ON THE POLEWARD SIDE OF THE STR. THE HIGHLY
UNFAVORABLE ENVIRONMENT WILL CONTINUE TO RAPIDLY ERODE THE SYSTEM. CONCURRENTLY BY TAU 12, 15W WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) AND BY TAU 36, WILL TRANSFORM INTO A 75-KNOT HURRICANE-FORCE COLD-CORE LOW. 

MODEL DISCUSSION: NUMERICAL MODELS REMAIN IN VERY TIGHT AGREEMENT
WITH AN EVEN AND GRADUAL SPREAD TO A MERE 76NM BY TAU 36, LENDING
HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. THERE IS ONLY MEDIUM
CONFIDENCE IN THE INTENSITY FORECAST GIVEN THE UNCERTAINTIES
TYPICAL WITH ETT.

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