WDPN32 PGTW 212100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (CHAMPI) WARNING NR 35//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 25W (CHAMPI), LOCATED APPROXIMATELY 96 NM
SOUTH-SOUTHWEST OF IWO TO, JAPAN, HAS TRACKED EAST-NORTHEASTWARD AT
03 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY
SHOWS A SLIGHT INTENSIFICATION TREND WITH TIGHTLY-CURVED CONVECTIVE
BANDING WRAPPING INTO AN 18-NM RAGGED EYE, WHICH SUPPORTS THE
INITIAL POSITION WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 90
KNOTS IS BASED ON CONGRUENT DVORAK ESTIMATES FROM PGTW, KNES, RJTD.
UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH AN
ANTICYCLONE OVER THE CENTER AND IMPROVED POLEWARD OUTFLOW, ENHANCED
BY THE MIDLATITUDE WESTERLIES. TY 25W HAS STARTED TO RE-CURVE ALONG
THE NORTHWESTERN PERIPHERY OF THE STR.
3. FORECAST REASONING.
A. NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TY 25W WILL CONTINUE TO TRACK EAST-NORTHEASTWARD ALONG THE
NORTHERN PERIPHERY OF THE STR THROUGH THE FORECAST PERIOD. DUE TO
FAVORABLE CONDITIONS THROUGH TAU 24, PARTICULARLY THE ENHANCED
POLEWARD OUTFLOW AND WARM SSTS, TY 25W IS FORECAST TO INTENSIFY TO A
PEAK OF 95 KNOTS. AFTER TAU 36, ENVIRONMENTAL CONDITIONS WILL DEGRADE
LEADING TO A STEADY WEAKENING TREND. INCREASING VERTICAL WIND SHEAR
AND COOLER SSTS NEAR TAU 48 WILL FURTHER WEAKEN THE SYSTEM. TY 25W IS
FORECAST TO BEGIN EXTRA-TROPICAL TRANSITION (ETT) AS IT BEGINS TO
INTERACT WITH THE BAROCLINIC ZONE AND MIDLATITUDE WESTERLIES.
C. IN THE EXTENDED FORECAST PERIOD, TY 25W SHOULD COMPLETE ETT BY
TAU 96 WHILE ACCELERATING NORTHEASTWARD. DYNAMIC GUIDANCE REMAINS IN
TIGHT AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK,
WHICH IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS.//
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