WDPN31 PGTW 292100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W (EWINIAR) WARNING NR 
021//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.3N 133.9E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 330 NM EAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
WELL-DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH CURVED
CONVECTIVE BANDING ALONG THE WESTERN SEMICIRCLE AND WIDESPREAD
CONVECTIVE FLARING OVER THE EASTERN PORTION OF THE SYSTEM. THE WARM
CORE OF THE SYSTEM HAS BEEN STUBBORN, MAINTAINING INTEGRITY DESPITE
SUBSTANTIAL DRY AIR ENTRAINMENT COMING IN THROUGH THE WESTERN
SEMICIRCLE. ANIMATED WATER VAPOR IMAGERY REVEALS SUBSTANTIAL
POLEWARD OUTFLOW TO THE NORTHEAST AND EQUALLY SUBSTANTIAL
IMPINGEMENT OVER THE SOUTHEAST QUADRANT. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON A MICROWAVE EYE IN A 291628Z
AMSR2 37H IMAGE, WHICH ALSO LENDS HIGH CONFIDENCE TO CURRENT
POSITION. THE MICROWAVE EYE ALSO LENDS CERTAINTY TO THE INITIAL
INTENSITY ASSESSMENT DESPITE AN ABUNDANCE OF LOWER AUTOMATED
ASSESSMENTS. AGENCY DVORAKS ARE ASSESSING THE STORM MORE
ACCURATELY. THE INTENSITY ASSESSMENT IS GROUNDED IN SUBJECTIVE
DVORAKS FROM JTWC OF 3.5-4.0 AND JMA OF 3.0-3.5 WHICH ARE MORE 
ACCURATE.

INITIAL WIND RADII BASIS: 291152Z SCATTEROMETER DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 51 KTS AT 291613Z
   CIMSS ADT: 47 KTS AT 291730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 30+ KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT INTO THE WESTERN SEMICIRCLE.

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 01W IS EXPECTED TO CONTINUE TRACKING
NORTHEASTWARD, STEERED BY THE WELL-DEFINED STR POSITIONED TO THE
EAST THROUGH THE NEXT 24 HOURS, THEN ROLL OVER TO A MORE
EAST-NORTHEASTERLY TRACK AFTER TAU 24. THE INTENSITY IS EXPECTED TO
DECREASE AT LEAST TILL TAU 36 DUE TO MOSTLY UNFAVORABLE CONDITIONS
- INCREASING VERTICAL WIND SHEAR (VWS), DECREASING SEA SURFACE
TEMPERATURES, AND DIMINISHING OCEAN HEAT CONTENT. THE GFS
700MB-300MB RELATIVE HUMIDITY CHART INDICATES THAT THE DRY AIR
INTRUSION WILL CONTINUE THROUGH THE NEXT 36 HOURS BUT THE CORE WILL
MAINTAIN INTEGRITY. AFTER TAU 36, CONDITIONS WILL BECOME SLIGHTLY
LESS UNFAVORABLE AS DRY AIR ENTRAINMENT EASES. MODEL GUIDANCE
INDICATES AN UPTICK IN INTENSITY AS THE SYSTEM BECOMES AN
EXTRATROPICAL LOW. 

MODEL DISCUSSION: THE DETERMINISTIC AND ENSEMBLE MODELS REMAIN IN
VERY STRONG AGREEMENT IN REGARD TO THE STORM'S TRACK AND SPEED,
WITH CROSS TRACK SPREAD OF 81NM AND SPEED TRACK SPREAD OF 104NM.
THE MAJORITY OF THE MODELS, INCLUDING THE JTWC MULTI-MODEL
CONSENSUS, SUPPORT THE EXPECTED INCREASE IN INTENSITY AROUND TAU 48
AS THE SYSTEM COMPLETES EXTRATROPICAL TRANSITION.

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