WDPN31 PGTW 222100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (SURIGAE) WARNING NR 038//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 02W (SURIGAE), LOCATED APPROXIMATELY 302 NM SOUTH OF 
KADENA AB, HAS TRACKED EAST-NORTHEASTWARD AT 11 KNOTS (KTS) OVER THE 
PAST SIX HOURS. THE INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE 
BASED ON A 221702Z AMSR2 89 GHZ MICROWAVE IMAGE THAT ALSO REVEALS 
DEEP CONVECTION OVER THE EASTERN SEMICIRCLE. ADDITIONALLY, THE 
POSITION IS LOCATED NEAR THE PGTW AND RJTD SATELLITE FIXES. THE 
LARGE CONCENTRIC EYE HAS FILLED DURING THE LAST 24 HOURS AND THE 
CLOUD SHIELD HAS BECOME INCREASINGLY ASYMMETRIC. INCREASING DRY AIR 
ENTRAINMENT IS SUPPRESSING THE CONVECTION ALONG THE WESTERN 
SEMICIRCLE OF THE STORM. THE INTENSITY ASSESSMENT OF 80 KTS IS HELD 
SLIGHTLY HIGHER THAN MULTI-AGENCY DVORAK INTENSITY ESTIMATES AND IS 
IN GOOD AGREEMENT WITH AN ADT OF T4.8 (84 KTS). SATCON REMAINS 
HIGHER AT 100 KTS. THERE IS FAIR CONFIDENCE IN THE INITIAL INTENSITY 
OF 80 KTS BASED ON THE CURRENT FORECAST TREND. WIND RADII HAVE BEEN 
UPDATED WITH A 221234Z ASCAT-C PASS. VERTICAL WIND SHEAR OVER THE 
STORM IS APPROACHING 20 KTS AND SEA SURFACE TEMPERATURE IS 26-27C. 
TY 02W IS TRACKING ALONG THE NORTHWESTERN PERIPHERY OF A SUBTROPICAL 
RIDGE POSITIONED TO THE SOUTHEAST. 
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY 
SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 02W IS BEHAVING AS EXPECTED, HAVING ROLLED OVER TO AN 
EASTERLY TRACK IN THE PAST 24 HOURS. A ZONE OF HIGHER VERTICAL WIND 
SHEAR IS EXPECTED TO PERSIST FOR THE DURATION OF THE FORECAST. WHEN 
COUPLED WITH ALONG TRACK SEA SURFACE TEMPERATURES OF 25-27C, THE 
SYSTEM WILL CONTINUE ALONG A WEAKENING TREND. A SERIES OF TWO SHORT 
WAVES WILL DRIVE THE FORECAST SCENARIO OVER THE NEXT 72 HOURS. THE 
FIRST SHORTWAVE, CURRENTLY POSITIONED OVER THE TAIWAN STRAIT, WILL 
ERODE THE SYSTEM BETWEEN TAU 24 AND 36. A SECOND, MORE VIGOROUS 
SHORTWAVE WILL THEN IMPACT THE SYSTEM AND INDUCE AN EXTRA-TROPICAL 
TRANSITION (ETT) PERIOD AROUND TAU 48. THE MAJORITY OF MODEL 
GUIDANCE DEPICTS THE ETT SCENARIO. HOWEVER, THERE IS SIGNIFICANT 
SPREAD IN ALONG TRACK SPEEDS IN THE LATER TAUS. THE LONE OUTLIER IS 
THE GFS MODEL, WHICH DEPICTS A DECAPITATION OF THE UPPER LEVELS, 
STALLING THE REMAINING LOW LEVEL VORTEX AS IT SLOWLY DISSIPATES. THE 
JTWC FORECAST TRACK HEDGES SLIGHTLY FASTER AND EQUATORWARD OF 
CONSENSUS, LEANING TOWARDS THE FORECAST ETT SCENARIO. THE INTENSITY 
FORECAST IS IN GOOD AGREEMENT WITH MODEL GUIDANCE, DEPICTING A STEEP 
WEAKENING TREND THROUGH TAU 36. AFTERWARDS, THE SYSTEM WILL MAINTAIN 
GALE FORCE WINDS AS IT UNDERGOES ETT.
  C. BY TAU 72, ETT WILL BE NEARLY COMPLETE, WITH THE CLOUD SHIELD 
EXTENDING  POLEWARD OF THE LLCC AND GALE FORCE WINDS EXTENDING FOR 
NEARLY 150NM OVER THE NORTHERN SEMICIRCLE. THE SYSTEM WILL CONTINUE 
TO ACCELERATE ALONG TRACK AS IT COMPLETES ETT AND MOVES INTO THE 
NORTH CENTRAL PACIFIC AS A MID-LATITUDE LOW BY TAU 96. OVERALL, 
THERE IS FAIR CONFIDENCE IN THE JTWC FORECAST TRACK.//
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