WDPN35 PGTW 181500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 22W (SOULIK) WARNING NR 13//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 22W (SOULIK), LOCATED APPROXIMATELY 76 NM WEST OF IWO TO, 
HAS TRACKED WEST-SOUTHWESTWARD AT 02 KNOTS OVER THE PAST SIX HOURS. 
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON AN 
APPROXIMATELY 20 NM RAGGED EYE WITH THE DEEPEST CONVECTION WEST OF 
THE LOW LEVEL CIRCULATION CENTER (LLCC) IN ANIMATED ENHANCED 
INFRARED SATELLITE IMAGERY. A 181111Z AMSU 89 GHZ IMAGE SUPPORTS THE 
INITIAL POSITION. THE CURRENT INTENSITY IS ASSESSED AT 100 KNOTS 
BASED ON THE PGTW DVORAK INTENSITY ESTIMATES OF T5.5 (102 KTS) AND A 
180902Z CIMSS SATCON ESTIMATE OF 101 KTS. THE ENVIRONMENT IS 
FAVORABLE FOR INTENSIFICATION WITH LOW (5-10 KTS) VERTICAL WIND 
SHEAR (VWS), WARM SEA SURFACE TEMPERATURES (28-29 CELSIUS), 
EXCELLENT POLEWARD OUTFLOW, AND GOOD EQUATORWARD OUTFLOW. TY 22W IS 
ALMOST STATIONARY BECAUSE THE SUBTROPICAL RIDGE (STR) TO THE EAST-
NORTHEAST IS BEING WEAKENED BY A MID-LATITUDE TROUGH TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE. 
   B. THE STR IS BUILDING BECAUSE THE MID-LATITUDE TROUGH IS MOVING 
TO THE EAST. IN THE NEXT FEW HOURS, TY 22W WILL ACCELERATE WEST-
NORTHWESTWARD TOWARD KYUSHU. THE PASSAGE OF THE TROUGH WILL 
SIGNIFICANTLY REDUCE THE POLEWARD OUTFLOW CHANNEL AND, BETWEEN TAU 
12 AND TAU 48, INTENSIFICATION WILL REMAIN AT A PEAK OF 105 KTS. 
AFTER TAU 48, TY 22W WILL START TO GRADUALLY WEAKEN. THE JTWC 
FORECAST TRACK FOLLOWS THE MULTI-MODEL CONSENSUS. THE SPREAD AMONG 
THE MEMBERS IS 170 NM AT TAU 72. THE INTENSITY FORECAST IS SLIGHTLY 
HIGHER THAN THE INTENSITY CONSENSUS. THROUGH TAU 72, CONFIDENCE IN 
THE JTWC FORECAST TRACK IS MODERATE BASED ON THE SPREAD IN THE MODEL 
GUIDANCE.   
   C. BETWEEN TAU 72 AND 96, A SHORTWAVE TROUGH IS EXPECTED TO 
WEAKEN THE STR AND ALLOW TY 22W TO RECURVE. AT THIS POINT, SPREAD IN 
THE MODEL GUIDANCE INCREASES DUE TO VARIATIONS IN THE TIMING AND 
TRACK SPEED OF THE CYCLONE. INCREASING VWS AND LIMITED LAND 
INTERACTION ARE EXPECTED TO WEAKEN TY 22W BEYOND TAU 96. 
EXTRATROPICAL TRANSITION IS EXPECTED TO BEGIN PRIOR TO TAU 120 AS 
THE TYPHOON MOVES INTO THE MID-LATITUDE WESTERLIES. CONFIDENCE IN 
THE FORECAST TRACK IS LOW FOR THIS PORTION OF THE FORECAST DUE TO 
HIGH UNCERTAINTY IN WHERE AND WHEN THE CYCLONE WILL RECURVE.//
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