WDPN33 PGTW 231500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 26W (FRANCISCO) WARNING NR 31//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 26W (FRANCISCO), LOCATED APPROXIMATELY 173 NM SOUTHEAST 
OF KADENA AB, HAS TRACKED WEST-NORTHWESTWARD AT 04 KNOTS OVER THE 
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) 
SHOWS THE LOW LEVEL CIRCULATION CENTER (LLCC) HAS STARTED TO DEVOLVE 
AS DEEP CONVECTION HAS CONTINUED TO STEADILY WEAKEN DUE TO THE 
CONTINUED EFFECTS OF MARGINAL SEA SURFACE TEMPERATURES (NEAR 26 
DEGREES CELSIUS) AND DRY AIR WRAPPING AROUND THE SYSTEM . A 231046Z 
SSMIS MICROWAVE IMAGE ALSO SHOWS DEVOLVING STRUCTURE AS THE 
CONVECTION HAS CONTINUED TO SHALLOW. THE CURRENT POSITION IS 
BASED UPON THE EIR LOOP, RADAR FIXES FROM RJTD, AND THE 
AFOREMENTIONED MICROWAVE IMAGE WITH HIGH CONFIDENCE. THE CURRENT 
INTENSITY HAS BEEN LOWERED TO 65 KNOTS BASED ON THE RAPIDLY 
DECREASING STRUCTURE AND FALLING DVORAK INTENSITY ESTIMATES FROM 
PGTW, KNES, AND RJTD. UPPER LEVEL ANALYSIS INDICATES A STRONG 
POLEWARD OUTFLOW CHANNEL CONTINUES TO BE ENHANCED BY THE MID-
LATITUDE WESTERLIES ALTHOUGH VERTICAL WIND SHEAR (VWS) HAS STARTED 
TO INCREASE TO MODERATE (15-20 KNOTS) LEVELS.  TY 26W HAS STARTED TO 
SLOW AS THE SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTHEAST OF THE 
SYSTEM BEGINS TO MODIFY IN RESPONSE TO AN APPROACHING MID-LATITUDE 
TROUGH THAT IS CURRENTLY LOCATED OVER THE KOREAN PENINSULA.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING.
   B. IN THE NEXT 24 HOURS, TY 26W IS EXPECTED TO BEGIN A SLOW TURN 
NORTH ALONG THE MODIFYING STR AS THE APPROACHING MID-LATITUDE 
TROUGH CONTINUES TO PROPAGATE EASTWARD TOWARDS JAPAN. AS TY 26W 
GAINS LATITUDE, THE MODIFYING STR WILL ACCELERATE TY 26W TO THE 
NORTHEAST. FURTHER DECREASING SSTS AND INCREASING VWS FROM THE 
TROUGH WILL LEAD TO A SLOW WEAKENING TREND THROUGH TAU 72.
   C. AFTER TAU 72, TY 26W WILL CONTINUE TO ACCELERATE TO THE 
NORTHEAST UNDER THE INFLUENCE OF THE MODIFYING STR AND PRESSING MID-
LATITUDE TROUGH. FURTHER WEAKENING IS EXPECTED WHILE THE SYSTEM 
TRACKS TO THE NORTHEAST AS ENVIRONMENTAL FACTORS CONTINUE TO ERODE 
THE SYSTEM. INTERACTION WITH THE BAROCLINIC ZONE AROUND TAU 72 WILL 
BEGIN THE EXTRA-TROPICAL TRANSITION PROCESS, WITH COMPLETE 
TRANSITION TO A COLD-CORE SYSTEM EXPECTED BY TAU 96. DYNAMIC MODEL 
GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 48, LENDING TO HIGH 
CONFIDENCE IN THE EARLY PORTION OF THE FORECAST. AFTER TAU 48, THE 
MODELS BEGIN TO DIVERGE AS THERE ARE SLIGHT VARIANCES IN THE EXTENT 
OF THE STR AS THE TROUGH MOVES INTO THE AREA. DUE TO THIS, LOW 
CONFIDENCE REMAINS IN THE EXTENDED FORECAST WHICH IS LAID CLOSE TO, 
BUT SLIGHTLY FASTER THAN, MULTI-MODEL CONSENSUS.//
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