Tropical Storm TALIM Advisory Вс, 17.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 20W (TALIM) WARNING NR
33//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 20W (TALIM), LOCATED APPROXIMATELY 184 NM SOUTH-
SOUTHWEST OF SASEBO, JAPAN, HAS TRACKED NORTHEASTWARD AT 11 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS DEEPENING CONVECTION ON THE WESTERN SEMI-CIRCLE
WRAPPING INTO A LOW LEVEL CIRCULATION CENTER. THE INITIAL POSITION
IS PLACED WITH FAIR CONFIDENCE BASED ON THE ANIMATED RADAR IMAGERY
FROM JMA AND EXTRAPOLATION FROM A 161309Z METOP-B ASCAT IMAGE. THE
INITIAL INTENSITY OF 55 KNOTS IS HEDGED ON THE LOWER END OF MULTI
AGENCY DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM T3.5 TO T4.0
FROM PGTW AND RJTD RESPECTIVELY. THE INTENSITY ESTIMATE IS SUPPORTED
BY THE PREVIOUSLY MENTIONED ASCAT IMAGE SHOWING 55 KNOT WIND BARBS
AND A SATCON ESTIMATE OF 51 KNOTS. ENVIRONMENTAL ANALYSIS SHOWS THE
SYSTEM HAS A STRONG POLEWARD OUTFLOW CHANNEL THAT IS ENHANCED BY THE
MID-LATITUDE JET WHILE THE EQUATORWARD OUTFLOW IS BEING SUPPRESSED
BY A RIDGE BUILDING TO THE SOUTHEAST. TS 20W IS LOCATED IN AN AREA
OF HIGH (20-25 KNOTS) VERTICAL WIND SHEAR AND IS SLOWLY TRACKING
THROUGH AN AREA OF WARM (29 CELSIUS) SEA SURFACE TEMPERATURES BUT
LOWER OCEAN HEAT CONTENT. THE COMBINATION OF HIGH VERTICAL WIND
SHEAR AND LOW OCEAN HEAT CONTENT IS PREVENTING SIGNIFICANT
STRENGTHENING OF THE SYSTEM. TS TALIM IS ACCELERATING EAST-NORTHEAST
ALONG THE NORTHWESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE
(STR) TO THE SOUTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 20W WILL CONTINUE TO ACCELERATE NORTHEASTWARD AS IT TRACKS
ALONG THE NORTHWESTERN EDGE OF THE STR FOR THE DURATION OF THE
FORECAST. AS THE SYSTEM TRACKS TOWARDS SOUTHERN JAPAN, A BRIEF
PERIOD OF LIMITED INTENSIFICATION PRIOR TO MAKING LANDFALL AS AN
APPROACHING MID-LATITUDE TROUGH APPROACHES AND SEA SURFACE
TEMPERATURES INCREASE. THE INTENSIFICATION WILL BE LIMITED BY STRONG
VERTICAL WIND SHEAR THAT WILL PERSIST UNTIL LANDFALL WHICH WILL
OCCUR SHORTLY AFTER TAU 6. INITIAL LANDFALL WILL OCCUR TO THE SOUTH
OF SASEBO, THE SYSTEM WILL TRACK NORTHEAST ACROSS SOUTHERN HONSHU,
AND OUT INTO THE SEA OF JAPAN PRIOR TO TAU 24. SECONDARY LANDFALL
WILL OCCUR OVER SOUTHERN HOKKAIDO AROUND TAU 48. TS TALIM WILL BEGIN
TO INTERACT WITH THE APPROACHING MID-LATITUDE TROUGH AND BEGIN
EXTRATROPICAL TRANSITION, BECOMING FULLY EXTRATROPICAL BY TAU 72.
THE SYSTEM WILL CONTINUE TO TRACK TO THE NORTHEAST THROUGH THE SEA
OF OKHOTSK AS A COLD CORE LOW WITH A SUBSTANTIAL GALE FORCE WIND
FIELD. DYNAMIC MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT LENDING
HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.//
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