WDPN32 PGTW 080300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 15W (BOLAVEN)      
WARNING NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 9.5N 153.2E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 549 NM EAST-SOUTHEAST OF ANDERSEN AFB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A SLOWLY 
CONSOLIDATING LOW-LEVEL CIRCULATION WITH A BROAD, PARTIALLY EXPOSED 
CENTER POSITIONED ALONG THE EASTERN EDGE OF THE CONVECTIVE MASS. 
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY INDICATES VORTICAL HOT 
TOWERS PERSISTING OVER THE WESTERN QUADRANT WITH CLOUD TOP 
TEMPERATURES NEAR -83 C CORRESPONDING TO APPROXIMATELY 53,000 FEET. 
ANIMATED WATER VAPOR IMAGERY REVEALS A DEVELOPING POLEWARD OUTFLOW 
CHANNEL INTO THE SOUTHERN PERIPHERY OF A TUTT CELL LOCATED NEAR 19N 
158E, WITH SOUTHEASTERLY VERTICAL WIND SHEAR (VWS) IMPINGING ON THE 
SOUTHEASTERN QUADRANT OF THE SYSTEM. A 072342Z ASCAT-C BULLSEYE IMAGE 
SHOWS A WELL-DEFINED, ELONGATED CIRCULATION WITH 30 TO 35 KNOT WINDS 
OVER THE WESTERN QUADRANT. THIS ASCAT-C IMAGE SUPPORTS THE INITIAL 
POSITION WITH MEDIUM CONFIDENCE AND THE INITIAL INTENSITY ASSESSMENT 
OF 35 KNOTS WITH HIGH CONFIDENCE. ADT AND AIDT OBJECTIVE ESTIMATES 
REMAIN UNREALISTICALLY HIGH BUT THE 080100Z DPRINT ESTIMATE OF 34 
KNOTS AND THE PGTW DVORAK ESTIMATE ALSO BOLSTER THE INITIAL INTENSITY 
CONFIDENCE.    

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 57 KTS AT 072330Z

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: LOW

3. FORECAST REASONING.

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

FORECAST DISCUSSION: ALTHOUGH TS 15W IS CONSOLIDATING SLOWLY NOW,
ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR STEADY DEVELOPMENT
THROUGH TAU 36 AS THE SYSTEM TRACKS WEST-NORTHWESTWARD. AFTER TAU 36, 
THE UPPER-LEVEL AND LOW-LEVEL WILL BECOME VERTICALLY ALIGNED AND 
POLEWARD OUTFLOW WILL CONTINUE IMPROVING WITH A VERY FAVORABLE UPPER-
LEVEL TUTT PATTERN TO THE NORTHEAST AND EAST, WHICH WILL FUEL RAPID 
INTENSIFICATION (RI) AFTER TAU 48. ADDITIONALLY, WARM, DEEP WATER 
(HIGH OCEAN HEAT CONTENT) ALONG THE CURRENT FORECAST TRACK WILL 
SUPPORT RI. CONSEQUENTLY, TS 15W SHOULD NOT BE UNDERESTIMATED
AS IT TRACKS TOWARD AND OVER THE GUAM REGION WITH PEAK INTENSITY
VALUES INCREASING FROM 75 KNOTS AT TAU 48 TO 110 KNOTS AT TAU 72.
ADDITIONAL INTENSIFICATION WILL OCCUR AFTER TAU 72 AS THE SYSTEM
RECURVES NORTHWARD TOWARD A BREAK IN THE STR, WITH ENHANCED
POLEWARD OUTFLOW INTO A MIDLATITUDE SHORTWAVE TROUGH.     

MODEL DISCUSSION: DUE TO THE TIMELY ASCAT-C PASS, THERE IS INCREASED 
CONFIDENCE IN THE INITIAL POSITION AND, WITH THE EXCEPTION OF NAVGEM 
TRACKING THE CENTER DIRECTLY OVER GUAM, THE DETERMINISTIC GUIDANCE IS 
IN TIGHTER AGREEMENT WITH A 93 NM CROSS-TRACK SPREAD IN SOLUTIONS AT 
TAU 48, WITH THE MAJORITY OF TRACKERS NORTH OF GUAM. THE 071800Z GEFS 
AND EPS ENSEMBLES ALSO SHOW THE BULK OF THEIR SOLUTIONS NORTH OF 
GUAM, HOWEVER, THERE IS STILL SOME POTENTIAL FOR A TRACK CLOSER TO 
GUAM CONSIDERING THE UNCERTAINTY IN ASCERTAINING THE INITIAL 
POSITION. RELIABLE INTENSITY GUIDANCE SUPPORTS THE JTWC INTENSITY 
FORECAST WITH MEDIUM CONFIDENCE WITH THE COAMPS-TC (NAVGEM AND GFS 
VERSIONS) INDICATING RAPID INTENSIFICATION AFTER TAU 48. 
ADDITIONALLY, RAPID INTENSIFICATION GUIDANCE HAS TRIGGERED REFLECTING 
THE VERY FAVORABLE ENVIRONMENT FORECAST TO EVOLVE IN THE NEXT DAY OR 
SO. THE 071200Z COAMPS-TC INTENSITY PROBABILITY DATA ALSO PROVIDES 
EXCELLENT SUPPORT FOR RAPID INTENSIFICATION AFTER TAU 36 WITH 
PROBABILITIES JUMPING AS HIGH AS 85 PERCENT FROM TAU 60 TO TAU 84. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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