WDPN31 PGTW 300300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W (EWINIAR) WARNING NR 
022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.9N 134.9E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 388 NM EAST-NORTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: 
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TS 01W 
MAINTAINING ITS LOW-LEVEL CIRCULATION CENTER (LLCC), WITH SIGNIFICANT 
UPPER-LEVEL CONVECTIVE BANDING SHEARING RAPIDLY OFF TO THE EAST OF 
THE LLCC. AS THE SYSTEM BEGINS THE EXTRATROPICAL TRANSITION (ETT), THE 
UPPER-LEVEL POLEWARD OUTFLOW REMAINS IN PLACE. THE INITIAL POSITION 
AND INTENSITY ARE PLACED WITH HIGH CONFIDENCE BASED ON A 292056Z RCM-1 
SAR IMAGE AND SUPPORTED BY THE JTWC DVORAK ANALYSIS AND OTHER 
AUTOMATED FIXES.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 55 KTS AT 290130Z
   CIMSS ADT: 51 KTS AT 290130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 22-24 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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: TS EWINIAR IS FORECAST TO CONTINUE ON THE NORTH-
EASTERLY TRACK, TURNING EAST-NORTHEASTERLY BY TAU 24, CONTINUING TO BE 
STEERED BY A WELL-DEFINED STR POSITIONED TO THE EAST OF THE SYSTEM. 
INTENSITY IS EXPECTED TO KEEP DECREASING TOWARDS THE END OF THE 
FORECAST PERIOD DUE TO INCREASINGLY HOSTILE ENVIRONMENTAL CONDITIONS. 
VERTICAL WIND SHEAR IS EXPECTED TO INCREASE TO OVER 65 KNOTS BY TAU 
48, WITH SEA SURFACE TEMPERATURES DROPPING DOWN TO LESS THAN 16C BY 
THE SAME TIME FRAME. SLOWLY EASING DRY AIR ENTRAINMENT MENTIONED IN 
THE PREVIOUS FORECAST WILL NO LONGER BE A SIGNIFICANT FACTOR IN TERMS 
OF IMPACTS TO INTENSITY, THEREFORE THE UPTICK IN INTENSITY AT THE END 
OF THE FORECAST IS NO LONGER FORECAST TO OCCUR.

MODEL DISCUSSION: THE NUMERICAL WEATHER PREDICTION MODEL GUIDANCE 
REMAINS THE SAME, PRESENTING VERY STRONG AGREEMENT REGARDING BOTH THE 
TRACK AND INTENSITY. THERE IS ONLY A CROSS TRACK SPREAD OF 51NM AND 
ALONG TRACK SPREAD OF 75NM, GOOD AGREEMENT FOR A SYSTEM ACCELERATING 
INTO EXTRA TROPICAL TRANSITION. THE SLIGHT INCREASE IN INTENSITY 
AROUND TAU 36 IS NO LONGER IN THE FORECAST DUE TO MOST OF THE MODELS 
NO LONGER PROJECTING AN UPTICK IN INTENSITY NEAR THE END OF ETT, BUT 
RATHER A STEADY DECREASE IN INTENSITY TOWARDS THE COMPLETION OF THE 
ETT BETWEEN TAU 36 AND TAU 48.

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