WDPN31 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (WIPHA) WARNING NR 13//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON 25W (WIPHA), LOCATED APPROXIMATELY 405 NM SOUTHWEST OF
IWO TO, HAS TRACKED NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX
HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) DEPICTS A
RAPIDLY DEVELOPING EYE WITH A CONCENTRIC EYEWALL OVER THE PAST FEW
HOURS. DUAL BANDS OF DEEP CONVECTION HAVE WRAPPED AROUND THE ENTIRE
PERIMETER OF THE LOW LEVEL CIRCULATION CENTER (LLCC). THE EYE ITSELF
HAS EXPANDED, RANGING FROM 15 TO 20 NM BASED ON THE EIR. ANIMATED
WATER VAPOR IMAGERY INDICATES STRONG RADIAL OUTFLOW WITH AN ENHANCED
POLEWARD OUTFLOW CHANNEL HAVE HELPED TO RAPIDLY INTENSIFY TY 25W
OVER THE PAST 18 HOURS. UPPER LEVEL ANALYSIS INDICATES THE
DEVELOPMENT OF A POINT SOURCE ANTICYCLONE OVER THE LLCC HAS BEEN
PROVIDING THE VERY FAVORABLE OUTFLOW OVER THE PAST SIX TO TWELVE
HOURS, IN ADDITION TO THE AFOREMENTIONED POLEWARD CHANNEL BEING
ENHANCED BY A MID-LATITUDE TROUGH LOCATED TO THE NORTH OF THE
SYSTEM. THE CURRENT INTENSITY OF 115 KNOTS IS SUPPORTED BY DVORAK
ESTIMATES FROM PGTW AND KNES, WITH CIMSS SATCON INDICATING 113
KNOTS. TY 25W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE
DEEP-LAYERED STR TO THE NORTHEAST.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TY 25W WILL CONTINUE TO TRACK TO THE NORTHWEST AS IT
PROGRESSES ALONG THE SOUTHWESTERN PERIPHERY OF THE STR OVER THE NEXT
24 HOURS. FAVORABLE ENVIRONMENTAL CONDITIONS WILL ALLOW THE SYSTEM
TO REACH A PEAK INTENSITY OF 125 KNOTS BY TAU 12, PRIOR TO ROUNDING
THE STR. BY TAU 36, THE SYSTEM WILL TURN TO THE NORTHEAST AND WILL
BEGIN A SPEEDY EXTRATROPICAL TRANSITION (ETT) AROUND TAU 60, AS THE
SYSTEM IS PASSING JUST TO THE EAST OF JAPAN.
C. IN THE EXTENDED TAUS, AN INCREASINGLY UNFAVORABLE ENVIRONMENT
AND INTERACTION WITH THE MID-LATITUDE BAROCLINIC ZONE WILL CAUSE TY
25W TO ACCELERATE THE ETT PROCESS, WITH COMPLETE ETT SLIGHTLY AFTER
TAU 72. TY 25W IS EXPECTED TO REMAIN A STRONG EXTRA-TROPICAL LOW
WELL INTO THE NORTHERN PACIFIC. BASED ON GOOD AGREEMENT IN THE MODEL
GUIDANCE, THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK.//
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