WDPN33 PGTW 240300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 26W (FRANCISCO) WARNING NR 33//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 26W (FRANCISCO), LOCATED APPROXIMATELY 129 NM SOUTHEAST 
OF KADENA AB, HAS TRACKED NORTH-NORTHWESTWARD AT 02 KNOTS OVER THE 
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) 
DEPICTS AN ALMOST QUASI-STATIONARY SYSTEM WITH SLIGHTLY IMPROVED 
CENTRAL CONVECTION OVER A LOW-LEVEL CIRCULATION CENTER (LLCC) THAT 
HAS SLIGHTLY DEVOLVED OVER THE PAST 12 HOURS. OVERALL, DEEP 
CONVECTION HAS SHALLOWED DUE TO THE CONTINUED EFFECTS OF MARGINAL 
SEA SURFACE TEMPERATURES (NEAR 26 DEGREES CELSIUS) AND DRY AIR 
ENTRAINMENT, HOWEVER, TY 26W HAS MAINTAINED ITS STRUCTURE RELATIVELY 
WELL AS IT SLOWLY TRACKS AROUND THE WESTERN PERIPHERY OF THE 
SUBTROPICAL RIDGE (STR). A 232316Z SSMIS MICROWAVE IMAGE REVEALS THE 
DEVOLVING STRUCTURE OF THE BROADENED LLCC AS THE CONVECTION HAS 
SIGNIFICANTLY SHALLOWED. THE CURRENT POSITION IS BASED UPON THE MSI 
LOOP, RADAR FIXES FROM RJTD, AND THE AFOREMENTIONED MICROWAVE IMAGE 
WITH HIGH CONFIDENCE. THE CURRENT INTENSITY HAS BEEN MAINTAINED AT 
65 KNOTS BASED ON THE HIGH END OF DVORAK INTENSITY ESTIMATES FROM 
PGTW 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 (15-25 KNOTS) LEVELS.  TY 26W HAS SIGNIFICANTLY 
SLOWED AS THE 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 12 HOURS, TY 26W IS EXPECTED TO SLOWLY TURN NORTH 
AND ROUND THE MODIFYING STR. MEANWHILE, THE APPROACHING MID-LATITUDE 
TROUGH WILL CONTINUE 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. 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 AS THE SYSTEM TRACKS TO THE NORTHEAST 
AND ENVIRONMENTAL PARAMETERS CONTINUE TO ERODE THE SYSTEM. EXTRA-
TROPICAL TRANSITION AND INTERACTION WITH THE BAROCLINIC ZONE WILL 
BEGIN AROUND TAU 48, WITH COMPLETE TRANSITION TO A COLD-CORE SYSTEM 
EXPECTED BY TAU 72. 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 LATER TAUS 
WHICH IS LAID CLOSE TO, BUT SLIGHTLY FASTER THAN, MULTI-MODEL 
CONSENSUS.//
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