WDPN31 PGTW 271500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 08W (DAMREY) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 35.7N 144.4E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 231 NM EAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 24 KTS
   SIGNIFICANT WAVE HEIGHT: 31 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS SHOWS A
MEDIUM SIZED SYSTEM THAT HAS SLIGHTLY IMPROVED WITH DEEPENED CENTRAL
CONVECTION OVER THE LAST SIX HOURS AS IT CONTINUED TO ACCELERATE
NORTHWESTWARD. THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON A DIMPLE NEAR THE CENTER, AN INDICATION OF A
FORMATIVE EYE. THE INITIAL INTENSITY OF 60KTS IS ALSO ASSESSED
WITH HIGH CONFIDENCE BASED ON THE HIGH END OF AGENCY AND AUTOMATED
DVORAK ESTIMATES AND IS CONSISTENT WITH A FORMATIVE EYE. ANALYSIS
INDICATES A FAVORABLE ENVIRONMENT WITH WARM SST, LOW VWS, AND
STRONG VENTILATION ALOFT.

INITIAL WIND RADII BASIS: SMAP DATA.

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T2.5 - 35 KTS
   CIMSS ADT: 34 KTS AT 270840Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TY DAMREY WILL TRACK MORE NORTH-NORTHWESTWARD
UNDER THE STR AS A MID-LATITUDE TROUGH TRANSITING FROM THE
NORTHWEST WEAKENS THE STR. THE CYCLONE WILL CREST THE STR AXIS
AROUND TAU 12 THEN ACCELERATE NORTHEASTWARD. THE FAVORABLE
ENVIRONMENT WILL SUSTAIN THE CURRENT INTENSITY OF 65KTS UP TO TAU
12. AFTERWARD, INCREASING VWS AND COOLING SST WILL BEGIN TO ERODE
THE SYSTEM. CONCURRENTLY BY TAU 24, TY 08W WILL ENTER THE COLD
BAROCLINIC ZONE AND BEGIN EXTRA-TROPICAL TRANSITION AND, BY TAU 36,
WILL TRANSFORM INTO A COLD-CORE LOW WITH EXPANDING STORM-FORCE
WINDS. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT WITH
GRADUAL AND EVEN SPREAD TO JUST 80NM BY TAU 36, LENDING HIGH
CONFIDENCE TO THE JTWC TRACK FORECAST.



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