Tropical Storm TALIM Advisory Sat Sep 16

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (TALIM) WARNING NR 27//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 20W (TALIM), LOCATED APPROXIMATELY 170 NM WEST-NORTHWEST
OF KADENA AB, HAS TRACKED EAST-NORTHEASTWARD AT 06 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A
BROAD AND RAGGED EYE FEATURE WITH LITTLE IMPROVEMENT IN THE
CONVECTIVE STRUCTURE OVER THE LAST SIX HOURS. A 150657Z SSMIS PASS
SHOWS AN ELONGATED LOW-LEVEL STRUCTURE WITH THE UPPER-LEVEL EYE
DISPLACED APPROXIMATELY 30 NM TO THE NORTHWEST AND DEEP CONVECTION
CONFINED TO THE WESTERN SEMICIRCLE. THERE IS FAIR CONFIDENCE IN THE
INITIAL POSITION DUE TO THE DISCREPANCY IN AGENCY SATELLITE FIXES
AND THE OBSERVED LOW-LEVEL STRUCTURE OBSERVED IN THE AFOREMENTIONED
37GHZ MICROWAVE IMAGE. THE INITIAL INTENSITY IS ASSESSED AT 80
KNOTS, BASED ON PERSISTENCE FROM THE PREVIOUS FORECAST WITH NO
SIGNIFICANT CHANGES IN CONVECTIVE STRUCTURE OR SUBJECTIVE DVORAK
ESTIMATES. UPPER-LEVEL ANALYSIS SHOWS MODERATE TO FAVORABLE VERTICAL
WIND SHEAR ASSOCIATED WITH A BUILDING RIDGE TO THE SOUTHEAST
HINDERING EQUATORWARD OUTFLOW. POLEWARD OUTFLOW REMAINS ROBUST
FEEDING INTO THE MID-LATITUDE JET. DUE TO THE QUASI-STATIONARY
MOTION OF TY 20W OVER THE LAST 24 HOURS, OCEAN UPWELLING HAS BROUGHT
COOLER WATERS TO THE SURFACE LEADING TO A WEAKENING TREND. HOWEVER,
THE WEAKENING TREND APPEARS TO HAVE STABILIZED AS TY 20W IS NOW
ACCELERATING EAST-NORTHEASTWARD AROUND A DEEP-LAYERED SUBTROPICAL
RIDGE TO THE SOUTHWEST.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE. HOWEVER, THE INTENSITY IS
ELEVATED TO 80 KNOTS JUST PRIOR TO MAKING LANDFALL SOUTHEAST OF
SASEBO, JAPAN.
   B. TY 20W WILL CONTINUE TO TRACK EAST-NORTHEASTWARD ALONG THE
NORTHWESTWARD PERIPHERY OF THE SUBTROPICAL RIDGE. SSTS IN THE REGION
ARE EXPECTED TO IMPROVE AS THE SYSTEM MOVES AWAY FROM THE AREA OF
UPWELLED WATER. UPPER-LEVEL CONDITIONS WILL REMAIN NEUTRAL FOR THE
NEXT 36 TO 48 HOURS AS ENHANCED POLEWARD OUTFLOW TAPPING INTO A
DEEPENING MID-LATITUDE TROUGH COMPETES WITH MODERATE SOUTHERLY WIND
SHEAR ASSOCIATED WITH THE UPPER-LEVEL SUBTROPICAL RIDGE. THE
INTENSITY IS FORECAST TO REMAIN STEADY AROUND 80 KNOTS OVER THE NEXT
48 HOURS AS THE SYSTEM MAKES LANDFALL SOUTHEAST OF SASEBO, JAPAN
AROUND TAU 42. AROUND TAU 48 THE UPPER-LEVEL TROUGH WILL BEGIN
INTERACTING WITH TY 20W INCREASING VERTICAL WIND SHEAR COUPLED WITH
STRONG BAROCLINIC SUPPORT. TY 20W WILL TRANSITION INTO A SIGNIFICANT
EXTRATROPICAL LOW BY TAU 72. DYNAMIC MODEL GUIDANCE SHOWS VERY TIGHT
GROUPING THROUGH THE 72 HOUR FORECAST, LENDING HIGH CONFIDENCE TO
THE JTWC FORECAST TRACK.//
NNNN
NNNN