WDPN31 PGTW 071500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 19W (VONGFONG) WARNING 
NR 20//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 19W (VONGFONG), LOCATED APPROXIMATELY 649 NM
SOUTHEAST OF KADENA AB, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE 
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY 
INDICATES A CONSOLIDATING SYSTEM WITH A 21-NM ROUND EYE SURROUNDED 
BY A SYMMETRIC ANNULUS OF INTENSE CONVECTION. A 071012Z SSMIS IMAGE 
ALSO DEPICTS A WELL-ORGANIZED STRUCTURE WITH EXTENSIVE FEEDER BANDS. 
BASED ON THE EYE, THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION. 
THE INITIAL INTENSITY IS ASSESSED AT 135 KNOTS, SUPER TYPHOON 
STRENGTH, BASED ON DVORAK INTENSITY ESTIMATES RANGING FROM 127 TO 
140 KNOTS. STY 19W HAS CONTINUED TO RAPIDLY INTENSIFY OVER THE PAST 
SIX HOURS AND HAS INCREASED 45 KNOTS IN THE PAST 24 HOURS. UPPER-
LEVEL ANALYSIS INDICATES LOW VERTICAL WIND SHEAR AND MULTIPLE 
OUTFLOW MECHANISMS, INCLUDING A TUTT CELL POSITIONED TO THE EAST. 
STY 19W CONTINUES TRACKING GENERALLY WESTWARD ALONG THE SOUTHERN 
PERIPHERY OF A DEEP-LAYERED SUBTROPICAL STEERING RIDGE.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY 
FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. STY 19W WILL CONTINUE TRACKING WEST-NORTHWESTWARD UNDER THE 
STEERING INFLUENCE OF THE CURRENT STEERING RIDGE THROUGH TAU 24. 
THEREAFTER, A MID-LATITUDE TROUGH PASSING TO THE NORTH IS EXPECTED 
TO WEAKEN THE STEERING RIDGE, CAUSING THE CYCLONE TO MAKE A SHARP 
POLEWARD TURN. THE CYCLONE SHOULD CONTINUE TRACKING GENERALLY 
POLEWARD ALONG THE STEERING RIDGE PERIPHERY FROM TAU 24 THROUGH TAU 
72. THE DYNAMIC CONSENSUS MODEL GUIDANCE IS IN GENERALLY FAIR
AGREEMENT THROUGH TAU 72. FAVORABLE UPPER-LEVEL CONDITIONS AND 
PASSAGE OVER VERY WARM WATER SHOULD ALLOW THE SYSTEM TO REACH PEAK 
INTENSITY DURING THIS PERIOD.
   C. STY 19W WILL CONTINUE POLEWARD ALONG THE WESTERN EDGE OF THE 
STEERING RIDGE DURING THE EXTENDED FORECAST PERIOD. A TRANSIENT 
RIDGE IS EXPECTED TO BUILD TO THE NORTH OF THE SYSTEM LATE IN THE 
FORECAST PERIOD, INDUCING A SLIGHT WESTWARD TRACK DEFLECTION BETWEEN 
TAU 96 AND TAU 120. DYNAMIC MODEL GUIDANCE SUPPORTS THIS FORECAST 
SCENARIO, BUT DEPICTIONS OF THE WESTWARD TRACK DEVIATION VARY.  
GIVEN THIS UNCERTAINTY, THE CURRENT EXTENDED FORECAST TRACK LIES IN 
THE MIDDLE OF THE FORECAST GUIDANCE NEAR THE MULTI-MODEL CONSENSUS.  
STY 19W IS EXPECTED TO WEAKEN SLIGHTLY IN THE EXTENDED PERIOD AS 
UPPER-LEVEL OUTFLOW BECOMES LESS FAVORABLE AND ALONG-TRACK OCEAN 
HEAT CONTENT DROPS OFF. OVERALL, THERE IS LOW CONFIDENCE IN THE 
FORECAST TRACK.//
NNNN