Tropical Storm TALIM Advisory 18 Σεπ.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 20W (TALIM) WARNING NR
37//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 20W (TALIM), LOCATED APPROXIMATELY 128 NM NORTH-
NORTHWEST OF YOKOTA AB, HAS TRACKED NORTHEASTWARD AT 47 KNOTS
OVER THE PAST SIX HOURS. THE CURRENT POSITION IS PLACED WITH LOW
CONFIDENCE BASED ON MULTIAGENCY POSITION FIXES AND ANIMATED RADAR
IMAGERY FROM JMA. THE POOR OVERALL STRUCTURE OF THE STORM LENDS A
HIGH DEGREE OF UNCERTAINTY IN THE POSITION. THE INITIAL INTENSITY OF
55 KNOTS IS CONSISTENT WITH SYNOPTIC OBSERVATIONS AND SLIGHTLY BELOW
A PGTW EXTRATROPICAL CURRENT INTENSITY ESTIMATE OF T4.0 (65 KNOTS).
TS 20W CONTINUES TO RAPIDLY ACCELERATE TO THE NORTHEAST AS IT TRACKS
BETWEEN A SUBTROPICAL RIDGE TO THE SOUTHEAST AND A MID-LATITUDE
TROUGH TO THE NORTHWEST. THE ENVIRONMENT HAS BECOME INCREASINGLY
UNFAVORABLE AS THE STORM TRACKS OVER COOL (25 CELSIUS) WATERS AND
THROUGH AN AREA OF HIGH (50+ KNOTS) VERTICAL WIND SHEAR. TS TALIM
HAS BEGUN EXTRATROPICAL TRANSITION AS EVIDENT BY THE ASYMMETRIC
SHAPE AND RAPID ACCELERATION IN FORWARD MOTION AS IT MERGES WITH THE
MID-LATITUDE TROUGH.
3. FORECAST REASONING.
   A. THE FORECAST TRACK HAS AGAIN SHIFTED SLIGHTLY TO THE EAST
BASED ON THE RECENT STORM MOTION. HOWEVER, THERE IS NO SIGNIFICANT
CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC
REASONING MESSAGE.
   B. TS 20W WILL CONTINUE TO TRACK TO THE NORTHWEST FOR THE
DURATION OF THE FORECAST PERIOD. THE SYSTEM IS FORECAST TO COMPLETE
EXTRATROPICAL TRANSITION. INTERACTION WITH THE MID-LATITUDE TROUGH
THROUGHOUT THE TRANSITION WILL ALLOW 20W TO MAINTAIN AN EXPANSIVE
AREA OF GALE FORCE WINDS. GIVEN THE SIZE AND INTENSITY OF THE WIND
FIELD, POTENTIALLY SIGNIFICANT WEATHER IMPACTS ARE POSSIBLE
THROUGHOUT JAPAN FOR THE NEXT 24 HOURS. DESPITE THE SLIGHT EASTWARD
SHIFT IN THE MODEL GUIDANCE, CONTINUED TIGHT AGREEMENT AMONG MODELS
LENDS HIGH CONFIDENCE IN THE CURRENT JTWC OFFICIAL TRACK FORECAST.//
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