WDPN32 PGTW 081500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 15W (BOLAVEN) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 9.8N 152.0E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 478 NM EAST-SOUTHEAST OF ANDERSEN AFB,
GUAM
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A
CONSOLIDATING SYSTEM WITH DEEP OVERSHOOTING AND EXPANDING
CONVECTION IN THE CENTRAL DENSE OVERCAST THAT IS OBSCURING THE LOW
LEVEL CIRCULATION. THE INITIAL POSITION AND INTENSITY ARE PLACED WITH 
HIGH CONFIDENCE BASED ON A 081047Z ASCAT BULLSEYE PASS. THE INTENSITY 
IS ALSO SUPPORTED BY THE MEDIAN OF AGENCY AND AUTOMATED DVORAK 
ESTIMATES AND REFLECTS THE GRADUAL CONSOLIDATION. ANALYSIS INDICATES 
A FAVORABLE ENVIRONMENT WITH MODERATE POLEWARD OUTFLOW AND VERY WARM
ALONG-TRACK SST OFFSET BY MODERATE VWS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

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


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 55 KTS AT 081130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TS 15W WILL TRACK NORTHWESTWARD UNDER THE
STEERING INFLUENCE OF AN EXTENSION THE STR TO THE NORTHEAST AND
WILL COME TO WITHIN 62NM OF ANDERSEN AFB AS IT TRACKS NORTHEAST OF
GUAM JUST BEFORE TAU 48. AFTERWARD, THE STR TO THE NORTH WILL
RECEDE EASTWARD AND ASSUME STEERING AND DRIVE THE SYSTEM NORTHWARD
TOWARD IWO TO. THE FAVORABLE ENVIRONMENT WILL FUEL A STEADY 
INTENSIFICATION TO 80KTS AT TAU 48. AFTERWARD, LOW VWS AS THE CYCLONE 
ROUNDS THE STR AXIS AND INCREASING POLEWARD OUTFLOW AHEAD OF A MID-
LATITUDE TROUGH APPROACHING FROM THE NORTHWEST WILL PROMOTE A RAPID 
INTENSIFICATION TO A PEAK OF 125KTS BY TAU 96. AFTERWARD, INCREASING 
VWS WILL BEGIN TO ERODE THE SYSTEM DOWN TO 120KTS BY TAU 120.


MODEL DISCUSSION: NUMERICAL MODELS HAVE BECOME EVEN MORE TIGHT WITH
A GRADUAL AND EVEN SPREAD TO A MERE 112NM BY TAU 72 THEN TO 236NM
BY TAU 120, LENDING HIGH CONFIDENCE TO THE JTWC TRACK 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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