WDPN31 PGTW 290900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 01W (EWINIAR) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.7N 132.4E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 252 NM EAST OF KADENA AB, OKINAWA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 20 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS CONTINUED 
DETERIORATION ESPECIALLY ALONG THE NORTHERN HEMISPHERE DUE TO COLD 
LOW LEVEL DRY AIR INTRUSION, COOLING SST, AND INCREASING VWS. THE 
INITIAL POSITION, EXTRAPOLATED FROM RADAR FIXES AND A MICROWAVE EYE 
IN THE 290423Z AMSR2 36GHZ IMAGE, IS PLACED WITH HIGH CONFIDENCE. THE 
INITIAL INTENSITY IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON 
OVERALL ASSESSMENT OF AGENCY AND OBJECTIVE DVORAK ESTIMATES (SEE 
BELOW) AND REFLECTS THE 6-HR DETERIORATION. ANALYSIS REVEALS AN 
UNFAVORABLE ENVIRONMENT WITH COOLING SST, MODERATE TO HIGH VWS, AND 
COLD LOW LEVEL DRY AIR INTRUSION OFFSET BY STRONG POLEWARD AND 
EQUATORWARD OUTFLOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T4.0 - 65 KTS
   CIMSS SATCON: 62 KTS AT 290500Z
   CIMSS ADT: 41 KTS AT 290530Z
   CIMSS DPRINT: 62 KTS AT 290500Z
   CIMSS DMINT: 68 KTS AT 290412Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD
   OTHER FACTORS: COLD NORTHERLY DRY AIR INTRUSION IN THE LOW
LEVELS.   

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TYPHOON EWINIAR WILL CONTINUE ITS ACCELERATED
NORTHEASTWARD TRACK ON THE POLEWARD SIDE OF THE STEERING STR. THE
UNFAVORABLE ENVIRONMENT WILL CONTINUE TO GRADUALLY ERODE THE SYSTEM. 
CONCURRENTLY BY TAU 36, THE SYSTEM WILL BEGIN EXTRA-TROPICAL 
TRANSITION (ETT) AND BY TAU 72, TY 01W WILL BE REDUCED TO A 40-KT 
GALE-FORCE COLD-CORE LOW.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT, 
LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. HOWEVER, GIVEN
THE UNCERTAINTIES ASSOCIATED WITH ETT, THERE IS ONLY MEDIUM 
CONFIDENCE IN THE INTENSITY FORECAST. 

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