WDPN33 PGTW 281500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 27W (SAOLA) WARNING NR 36//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 27W (SAOLA), LOCATED APPROXIMATELY 157 NM NORTHEAST OF
KADENA AB, HAS TRACKED NORTHEASTWARD AT 18 KNOTS OVER THE PAST
SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS DEEP 
CONVECTIVE BANDING WRAPPING INTO AN APPROXIMATELY 15NM RAGGED EYE 
FEATURE. A 281243Z 89GHZ AMSU MICROWAVE IMAGE DEPICTS THAT THE 
DEEPEST CONVECTION IS WRAPPING INTO THE LLCC FROM THE EASTERN SEMI-
CIRCLE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED 
ON THE INFRARED LOOP AND RADAR IMAGERY FROM JMA WITH HIGH 
CONFIDENCE. THE INITIAL INTENSITY OF 70 KNOTS IS HEDGED ON THE 
UPPER END OF MULTI-AGENCY DVORAK INTENSITY ESTIMATES RANGING FROM 
T3.5 TO T4.5 (55-77 KNOTS) FROM RJTD AND PGTW RESPECTIVELY AND IS 
SUPPORTED BY SURFACE OBSERVATIONS FROM AMAMI OSHIMA SHOWING 67 
KNOTS SUSTAINED GUSTING TO 83. ENVIRONMENTAL ANALYSIS INDICATES THE 
SYSTEM IS IN AN AREA OF MODERATE TO STRONG (20-25 KNOT) VERTICAL 
WIND SHEAR (VWS) AND IS TRACKING THROUGH WARM (28 CELSIUS) SEA 
SURFACE TEMPERATURES. THE SYSTEM CURRENTLY HAS A VERY STRONG 
POLEWARD OUTFLOW CHANNEL DUE TO THE INTERACTION WITH THE MID-
LATITUDE WESTERLIES, AND A WEAKER EQUATORWARD OUTFLOW CHANNEL. 
HOWEVER, THE GOOD OUTFLOW CHANNELS ARE OFFSET BY SUBSIDENCE AND DRY 
AIR IN THE WESTERN SEMI-CIRCLE. TYPHOON SAOLA IS CURRENTLY TRACKING 
ALONG THE NORTHWESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL 
RIDGE (STR) LOCATED TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE. 
   B. TY SAOLA IS FORECAST TO RAPIDLY ACCELERATE AND TRACK TO THE 
NORTHEAST, SKIRTING ALONG THE SOUTHERN COAST OF JAPAN. THE 
MARGINALLY FAVORABLE ENVIRONMENT WILL ALLOW FOR BRIEF 
INTENSIFICATION OVER THE NEXT 12 HOURS, EVENTUALLY PEAKING AT 
AROUND 75 KNOTS. AFTER TAU 12, INCREASING VERTICAL WIND SHEAR WILL 
CAUSE THE SYSTEM TO BEGIN A GRADUAL WEAKENING TREND THAT WILL 
PERSIST FOR THE DURATION OF THE FORECAST. AROUND TAU 24, CONTINUED 
INTERACTION WITH A PASSING MID-LATITUDE TROUGH COMBINED WITH COOLER 
SEA SURFACE TEMPERATURES WILL CAUSE THE SYSTEM TO BEGIN EXTRA-
TROPICAL TRANSITION. TY SAOLA IS FORECAST TO BECOME A COLD CORE LOW 
WITH AN EXPANSIVE STORM-FORCE WIND FIELD BY TAU 48. AVAILABLE 
DYNAMIC MODEL GUIDANCE IS IN TIGHT AGREEMENT ON THE FORECAST TRACK 
AND THE ALONG TRACK SPEED. THE STRONG MODEL AGREEMENT LENDS HIGH 
CONFIDENCE TO THE JTWC TRACK FORECAST.//
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