Tropical Storm PHANFONE Advisory Mon Oct 06

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 18W (PHANFONE) WARNING NR 27//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 18W (PHANFONE), LOCATED APPROXIMATELY 502 NM
SOUTHWEST OF YOKOSUKA, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 13
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) SHOWS A 30-NM RAGGED EYE WITH WEAKENED SPIRAL BANDING.
THE INITIAL POSITION IS BASED ON THE EYE FEATURE ON THE MSI LOOP WITH
HIGH CONFIDENCE. THE INITIAL INTENSITY OF 90 KNOTS IS BASED ON AN
OVERALL ASSESSMENT OF DVORAK CURRENT INTENSITY ESTIMATES FROM ALL
REPORTING AGENCIES AND REFLECTS THE WEAKENING TREND. UPPER-LEVEL
ANALYSIS INDICATES TY 18W IS LOCATED IN AN AREA OF STRONG (GREATER
THAN 30 KNOTS) VERTICAL WIND SHEAR (VWS) OFFSET BY VIGOROUS OUTFLOW,
ESPECIALLY ON THE POLEWARD SIDE THAT IS SUSTAINING THE REMNANT
CONVECTION. TY 18W HAS ROUNDED THE WESTERN EDGE OF THE
DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE EAST AND HAS BEGUN TO
ACCELERATE NORTHEASTWARD INTO THE COLD MID-LATITUDE BAROCLINIC ZONE.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 18W WILL CONTINUE TO ACCELERATE NORTHEASTWARD AND BE QUICKLY
ABSORBED INTO THE BAROCLINIC ZONE AS IT UNDERGOES EXTRA-TROPICAL
TRANSITION. INCREASING VWS AND COOLING SEA SURFACE TEMPERATURES
WILL RAPIDLY ERODE THE SYSTEM BUT WILL STILL BE A VERY INTENSE STORM
FORCE COLD-CORE LOW BY TAU 24. THE AVAILABLE NUMERIC GUIDANCE REMAINS
IN TIGHT AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST
THAT IS LAID SLIGHTLY TO THE RIGHT OF AND FASTER THAN MULTI-MODEL
CONSENSUS.//
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