WDPN31 PGTW 252100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (DAMREY)       
WARNING NR 012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.1N 154.8E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 1075 NM SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED PROXYVIS SATELLITE IMAGERY DEPICTS A PARTIALLY EXPOSED,
DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH CURVED DEEP
CONVECTIVE BANDING OVER THE EASTERN SEMICIRCLE. A 251528Z AMSR2
COLOR COMPOSITE 37 GHZ MICROWAVE IMAGE REVEALS SHALLOW BANDING AND
A BROAD, DEFINED LLCC OVER THE WESTERN SEMICIRCLE WITH DEEP
CONVECTIVE BANDING OVER THE EASTERN SEMICIRCLE. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE PROXYVIS AND
AMSR2 IMAGERY. ANIMATED WATER VAPOR IMAGERY AND THE UW-CIMSS
MID-UPPER LEVEL WINDS PRODUCT INDICATE A ROBUST, JET-STRENGTH
POLEWARD OUTFLOW CHANNEL ENHANCED BY A STRONG UPPER-LEVEL LOW NEAR
28N 145E. THIS UNUSUALLY VIGOROUS POLEWARD CHANNEL IS PULLING MUCH
OF THE DEEP CONVECTION NORTH-NORTHWESTWARD, HINDERING CONVECTIVE
DEVELOPMENT. HOWEVER, A 251528Z AMSR2 WINDSPEED IMAGE SHOWS A
HIGHLY ASYMMETRIC WINDFIELD WITH A SWATH OF 45 TO 50 KNOT WINDS
OVER THE EASTERN QUADRANT. THE INITIAL INTENSITY OF 50 KTS IS
HEDGED ABOVE THE DVORAK CURRENT INTENSITY ESTIMATES FROM PGTW AND
KNES WITH MEDIUM CONFIDENCE BASED ON THE AMSR2 DATA.

INITIAL WIND RADII BASIS: AMSR2 WINDSPEED DATA

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 33 KTS AT 251730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TROPICAL STORM (TS) 08W IS FORECAST TO RECURVE
AROUND THE WESTERN PERIPHERY OF THE STR NEAR TAU 48, REMAINING WELL
EAST OF HONSHU. ENVIRONMENTAL CONDITIONS REMAIN SOMEWHAT CONDUCIVE,
WHICH SHOULD ALLOW THE SYSTEM TO GRADUALLY INTENSIFY TO A PEAK OF
65 KNOTS BY TAU 36. AFTER TAU 48, TS 08W WILL ACCELERATE
NORTHEASTWARD THEN EASTWARD AS IT INTERACTS WITH THE BAROCLINIC
ZONE AND MIDLATITUDE WESTERLIES. BY TAU 96, TS 08W WILL COMPLETE
EXTRA-TROPICAL TRANSITION AS IT TRANSITIONS INTO A COLD-CORE
BAROCLINIC LOW.   

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT
AGREEMENT THROUGH THE FORECAST PERIOD LENDING HIGH CONFIDENCE TO
THE JTWC TRACK FORECAST. RELIABLE INTENSITY GUIDANCE REMAINS IN
FAIR AGREEMENT WITH SIGNIFICANT UNCERTAINTY IN THE PEAK INTENSITY. 

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