WDPN32 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 15W (BOLAVEN) WARNING NR 
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.2N 149.4E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 303 NM EAST-SOUTHEAST OF ANDERSEN AFB,
GUAM
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A
CONSOLIDATING SYSTEM WITH TIGHT FORMATIVE BANDS INTERSECTING TOWARD
AN OBSCURED BUT DISCERNIBLE LOW LEVEL CIRCULATION CENTER (LLCC).
THE INITIAL POSITION AND INTENSITY ARE PLACED WITH HIGH CONFIDENCE
BASED ON THE LLCC IN THE MSI LOOP. THE INITIAL INTENSITY IS PLACED
WITH MEDIUM CONFIDENCE BASED ON THE OVERALL ASSESSMENT OF AGENCY
AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE GRADUAL
CONSOLIDATION.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO
THE NORTH AND NORTHEAST.


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.5 - 55 KTS
   KNES: T4.0 - 65 KTS
   CIMSS SATCON: 60 KTS AT 090311Z
   CIMSS ADT: 63 KTS AT 090530Z

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 15W WILL TRACK NORTHWESTWARD UNDER THE
STEERING INFLUENCE OF AN EXTENSION THE STR TO THE NORTHEAST AND
WILL COME TO WITHIN 61NM OF ANDERSEN AFB JUST AFTER TAU 24 AS IT
TRACKS NORTHEAST OF GUAM. AFTER TAU 36, THE STR TO THE NORTH WILL 
RECEDE EASTWARD AND ASSUME STEERING AND DRIVE THE SYSTEM NORTHWARD 
TOWARD IWO TO. THE HIGHLY FAVORABLE ENVIRONMENT WILL FUEL A STEADY 
THEN RAPID INTENSIFICATION AS THE CYCLONE ROUNDS THE STR AXIS, FUELED 
BY INCREASING POLEWARD OUTFLOW AHEAD OF A MID-LATITUDE TROUGH
APPROACHING FROM THE NORTHWEST, AND BY TAU 72 WILL PEAK AT 125KTS.
AFTERWARD, INCREASING VWS AND COOLING SST WILL RAPIDLY ERODE THE
SYSTEM DOWN TO 90KTS BY TAU 120. ALSO, AROUND TAU 96, BOLAVEN WILL
BEGIN EXTRA-TROPICAL TRANSITION, AND BY TAU 120, WILL TRANSFORM
INTO A HURRICANE-FORCE COLD-CORE LOW. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT WITH
A GRADUAL AND EVEN SPREAD TO A MERE 156NM BY TAU 72 THEN TO 241NM
BY TAU 120 SANS NAVGEM, THE EXTREME LEFT-OF-TRACK OUTLIER, LENDING
HIGH CONFIDENCE TO THE JTWC TRACK - LAID TO THE RIGHT OF CONSENSUS
TO OFFSET NAVGEM - UP TO TAU 72, THEN MEDIUM CONFIDENCE AFTERWARD.

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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