WDPN31 PGTW 230300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (SURIGAE) WARNING NR 039//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 02W (SURIGAE), LOCATED APPROXIMATELY 253 NM SOUTH OF 
KADENA AB, HAS TRACKED NORTHEASTWARD AT 13 KNOTS (KTS) OVER THE PAST 
SIX HOURS. TY 02W (SURIGAE) IS TRACKING TOWARDS THE BAROCLINIC ZONE 
IN GOOD AGREEMENT WITH PREVIOUS FORECAST EXPECTATIONS. ANIMATED 
WATER VAPOR IMAGERY AND CROSS SECTION DATA VERIFIES A SURGE IN DRY 
AIR ENTRAINMENT OVER THE WESTERN SEMICIRCLE WHICH IS WRAPPING 
TOWARDS THE LOW LEVEL CIRCULATION CENTER (LLCC). THE CLOUD SHIELD 
HAS SHEARED WELL TO THE NORTHEAST OF THE LLCC, BUT THE LOW LEVEL 
VORTEX REMAINS INTACT. THE INITIAL POSITION IS PLACED WITH GOOD 
CONFIDENCE BASED ON A 230035Z GMI 89GHZ MICROWAVE IMAGE THAT IS IN 
GOOD AGREEMENT WITH THE PGTW, RJTD, AND RCTP SATELLITE FIXES. THE 
MICROWAVE IMAGERY CONFIRMS THAT THE DEEP CONVECTION IS BEING 
SUSTAINED OVER THE EASTERN SEMICIRCLE, INDICATING AN INCREASINGLY 
ASYMMETRIC CLOUD SHIELD. THE INTENSITY ASSESSMENT OF 80 KTS IS BASED 
ON DVORAK CURRENT INTENSITY ASSESSMENTS OF T4.5 (77 KTS) FROM PGTW 
AND RJTD AND SUPPORTED BY AN ADT VALUE OF 80 KTS. TY SURIGAE HAS 
TRACKED INTO A ZONE OF HIGH VERTICAL WIND SHEAR AND FALLING SEA 
SURFACE TEMPERATURES AS IT MOVES ALONG THE PERIPHERY OF A 
SUBTROPICAL RIDGE TO THE SOUTHEAST. 
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY 
SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. IN THE NEAR TERM, TWO SHORTWAVES ARE EXPECTED TO IMPACT TY 
02W. THE FIRST SHORTWAVE IS NOT EXPECTED TO ALTER THE STEERING OR 
BAROTROPIC CORE OF THE SYSTEM. AFTERWARDS, A SHORTWAVE RIDGE BEHIND 
THE SYSTEM WILL DRIVE THE LLCC TO THE SOUTHWEST THROUGH TAU 36 WHEN 
THE SYSTEM WILL TURN TO THE NORTHEAST AND BEGIN TRACKING INTO THE 
BAROCLINIC ZONE. A SECOND, MORE VIGOROUS SHORTWAVE WILL THEN MOVE 
OVER THE SYSTEM NEAR TAU 48 AND CAUSE THE SYSTEM TO BEGIN 
EXTRATROPICAL TRANSITION (ETT). BY TAU 72, TY 02W IS EXPECTED TO 
COMPLETE ETT AS IT TRACKS INTO THE NORTH CENTRAL PACIFIC AS VIGOROUS 
GALE FORCE MID-LATITUDE LOW. MODEL GUIDANCE HAS COME INTO 
INCREASINGLY BETTER AGREEMENT OVER THE PAST 48 HOURS, BUT THERE 
CONTINUE TO BE VARIATIONS IN THE ALONG TRACK SPEEDS AS THE SYSTEM 
ACCELERATES INTO THE WESTERLIES. THE JTWC TRACK FORECAST REMAINS 
NEAR AND JUST AHEAD OF THE MULTI-MODEL CONSENSUS, PLACING GOOD 
CONFIDENCE IN THE JTWC TRACK FORECAST AS WELL AS THE TIMING OF ETT 
COMPLETION.//
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