WDPS31 PGTW 081500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03P (JASPER)     
WARNING NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.0S 156.5E
   INITIAL INTENSITY: 110 KTS
   GEOGRAPHIC REFERENCE: 628 NM EAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 40 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 03P HAS WEAKENED STEADILY DUE TO DRY AIR
ENTRAINMENT AND INCREASING VERTICAL WIND SHEAR (20-25 KNOTS).
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN
INCREASINGLY ASYMMETRIC CONVECTIVE STRUCTURE WITH DEEP CONVECTION
WRAPPING AROUND A CLOUD-FILLED EYE. FORTUNATELY, A 081115Z MHS 89
GHZ MICROWAVE IMAGE REVEALS A WEAK BUT DEFINED MICROWAVE EYE
FEATURE WITH DEEP CONVECTION OVER THE SOUTHERN AND WESTERN
SEMICIRCLES. ADDITIONALLY, MUCH OF THE OUTER DEEP CONVECTIVE
BANDING HAS ERODED DUE TO DRY AIR ENTRAINMENT LEAVING EXPOSED
SHALLOW BANDING. THE INITIAL POSITION IS BASED ON THE MHS IMAGE
WITH HIGH CONFIDENCE. THE INITIAL INTENSITY HAS FLUCTUATED BETWEEN
T5.5 AND T6.0 OVER THE PAST SIX HOURS BUT IS CURRENTLY ASSESSED AT
T6.0 BY ALL AGENCIES. HOWEVER, CIMSS OBJECTIVE INTENSITY ESTIMATES
SHOW A LARGER SPREAD OF INTENSITY ESTIMATES RANGING FROM 96 KNOTS
TO 117 KNOTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WEAK EXTENSION OF THE SUBTROPICAL RIDGE
(STR) TO THE EAST WITH A STRONG STR ENTRENCHED TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   KNES: T6.0 - 115 KTS
   ABRF: T6.0 - 115 KTS
   CIMSS ADT: 117 KTS AT 081120Z
   CIMSS AIDT: 103 KTS AT 081330Z
   CIMSS DPRINT: 96 KTS AT 081300Z
   
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 25-30 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 03P IS FORECASTED TO GRADUALLY TURN 
SOUTHWESTWARD TO WEST-SOUTHWESTWARD THROUGH TAU 48 AS IT TRANSITIONS 
TO THE STEERING INFLUENCE OF THE STR POSITIONED TO THE SOUTH. STEADY 
WEAKENING WILL OCCUR DUE TO STRONG DRY AIR ENTRAINMENT AND INCREASING 
(20 TO 30 KNOTS) VERTICAL WIND SHEAR (VWS) ASSOCIATED WITH AN UPPER-
LEVEL TROUGH IMPINGING ON THE WESTERN PERIPHERY OF THE SYSTEM. AFTER 
TAU 48, TC 03P WILL TRACK WESTWARD ALONG THE NORTHERN PERIPHERY OF 
THE STR TO THE SOUTH, WHICH IS EXPECTED TO MAINTAIN THROUGH TAU 120. 
ADDITIONAL WEAKENING WILL OCCUR THROUGH TAU 72, HOWEVER, 
REINTENSIFICATION IS ANTICIPATED IN THE LATER TAUS AS VWS RELAXES AND 
THE SYSTEM GOES THROUGH A RE-MOISTENING PHASE.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 72 WITH A CROSS-TRACK SPREAD OF 70 NM AT TAU 72. AFTER
TAU 72, GUIDANCE DIVERGES WITH A 244 NM CROSS-TRACK SPREAD AT TAU
120. THE 080000Z ECMWF ENSEMBLE AND THE 080600Z GFS ENSEMBLE ALSO
REVEAL INCREASING UNCERTAINTY AFTER TAU 72. RELIABLE INTENSITY
GUIDANCE NOW INDICATES INCREASING UNCERTAINTY AFTER TAU 72 WITH
MESOSCALE MODELS SPLIT ON REINTENSIFICATION. COAMPS-TC (GFS
VERSION) SHOWS A SHARP REINTENSIFICATION TREND WITH A PEAK INTENSITY
OF 88 KNOTS. HAFS-A HAD PREVIOUSLY INDICATED REINTENSIFICATION BUT 
NOW SHOWS A STEADY WEAKENING TREND THROUGH LANDFALL. EXAMINATION OF
THE HAFS-A 700-300 MB RELATIVE HUMIDITY CHARTS INDICATES THAT DRY
AIR ENTRAINMENT WILL CONTINUE TO HINDER DEVELOPMENT THROUGH THE
ENTIRE FORECAST. THE 080600Z COAMPS-TC ENSEMBLE INDICATES ONLY A 30
TO 40 PERCENT PROBABILITY OF MODERATE INTENSIFICATION AFTER TAU 72.

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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