WDPN33 PGTW 190300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 26W (FRANCISCO) WARNING 
NR 13//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON 26W (FRANCISCO), LOCATED APPROXIMATELY 936 NM 
SOUTHEAST OF KADENA AB, HAS TRACKED WEST-NORTHWESTWARD AT 07
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY (MSI) DEPICTS A HIGHLY SYMMETRICAL EYE FEATURE SURROUNDED BY 
AN EXTENSIVE DEEP CONVECTIVE EYEWALL AND A STRONG FEEDER BAND 
TIGHTLY WRAPPING ACROSS THE WESTERN PERIPHERY OF THE SYSTEM AND INTO 
THE STORM CENTER. AN 182238Z SSMIS MICROWAVE IMAGE REVEALS THE 
SYSTEM HAS MAINTAINED EXTENSIVE DEEP CONVECTION WITHIN THE EYEWALL 
AND THE MAIN FEEDER BAND. HOWEVER, THE IMAGE DOES INDICATE THE 
SOUTHEAST QUADRANT OF THE EYEWALL APPEARS TO HAVE SLIGHTLY WEAKENED 
AND MAY BE A PRELUDE TO THE BEGINNING OF AN EYEWALL REPLACEMENT 
CYCLE (ERC). THE CURRENT POSITION IS BASED ON THE MSI AND THE 
AFOREMENTIONED MICROWAVE IMAGE WITH HIGH CONFIDENCE. THE CURRENT 
INTENSITY HAS BEEN MAINTAINED AT 135 KNOTS BASED ON CONGRUENT DVORAK 
ESTIMATES FROM PGTW AND KNES AS WELL AS A 134 KNOT CIMSS SATCON 
ESTIMATE. UPPER-LEVEL ANALYSIS INDICATES A POINT SOURCE ANTICYCLONE 
REMAINS OVER THE SYSTEM, PROVIDING AMPLE RADIAL OUTFLOW AND LOW (05- 
10 KNOTS) VERTICAL WIND SHEAR (VWS). THE 14 NM EYE REMAINS CLOUD-
FREE AND HAS MAINTAINED A FAIRLY SYMMETRIC ORIENTATION AS THE SYSTEM 
TRACKS GENERALLY TO THE NORTHWEST UNDER THE INFLUENCE OF THE 
SUBTROPICAL RIDGE (STR) EXTENSION.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING.
   B. THROUGH TAU 72, STY 26W IS EXPECTED TO SLOWLY TRACK 
NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR LOCATED WELL 
TO THE NORTH OF GUAM. FAVORABLE ENVIRONMENTAL CONDITIONS OF LOW VWS, 
WARM SEA SURFACE TEMPERATURES (SSTS), AND AMPLE OUTFLOW WILL ALLOW 
STY 26W TO INTENSIFY TO A MAXIMUM OF 140 KNOTS BY TAU 12. ALONG THE 
FORECAST TRACK, ERCS HAVE THE POTENTIAL TO BRIEFLY WEAKEN THE SYSTEM 
AS AN EXPANDED EYEWALL REPLACES THE SMALLER INNER EYEWALL. THIS IS 
USUALLY FOLLOWED BY A SLIGHT RE-INTENSIFICATION AS THE NEW OUTER 
EYEWALL CONSOLIDATES. AFTER TAU 24, THE SYSTEM WILL START TO MOVE 
INTO LESS FAVORABLE SSTS, WHICH WILL IMPACT THE LOW LEVEL INFLOW, 
CAUSING A SLOW WEAKENING TREND TO BEGIN AND PERSIST THROUGH TAU 72. 
HOWEVER, AS THE SYSTEM CONTINUES FURTHER TO THE NORTH, A STRONG 
POLEWARD OUTFLOW CHANNEL MAY DEVELOP WHICH COULD HELP TO OFFSET THE 
COOLER SSTS AND MAINTAIN HIGHER INTENSITIES. 
   C. AFTER TAU 72, STY 26W WILL BEGIN TO ROUND THE WESTERN 
PERIPHERY OF THE STR, ALLOWING FOR A MORE NORTH-NORTHWESTWARD TRACK. 
A DECREASE IN SSTS AND AN INCREASE IN VWS WILL AMPLIFY THE WEAKENING 
TREND THROUGH TAU 120 WHEN THE SYSTEM IS EXPECTED TO BEGIN EXTRA-
TROPICAL TRANSITION. NUMERIC MODEL GUIDANCE REMAINS WIDELY DIVERGENT 
IN THE EXTENDED TAUS, DUE TO VARYING SOLUTIONS TO THE ORIENTATION OF 
THE STR AS A SERIES OF MID-LATITUDE TROUGHS PROGRESS TO THE NORTH. 
ALL OBJECTIVE AIDS, WITH THE EXCEPTION OF GFDN, ARE BEGINNING TO 
INDICATE A RECURVE SCENARIO, BUT WIDELY VARY IN POSITION AND TRACK 
SPEED OF THE SYSTEM. MODEL ENSEMBLES ALSO CONTINUE TO INDICATE A 
WIDE RANGE OF SOLUTIONS IN ENSEMBLE MEMBERS, LEAVING CONSIDERABLE 
UNCERTAINTY IN THE FORECAST TRACK AFTER TAU 72. THE CURRENT FORECAST 
REMAINS CLOSE TO THE MULTI-MODEL CONSENSUS AND IS HEDGED TOWARD THE 
ECMWF SOLUTION. DUE TO THE WEAKLY DEFINED STR EXTENSION, AND THE 
HIGH UNCERTAINTY IN THE EXTENDED TAUS, THE CONFIDENCE IN THE 
FORECAST REMAINS LOW.//
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