Tropical Storm TALIM Advisory 14.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (TALIM) WARNING NR 22//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 20W (TALIM), LOCATED APPROXIMATELY 172 NM WEST OF KADENA
AB HAS TRACKED NORTH-NORTHWESTWARD AT 07 KNOTS OVER THE PAST SIX
HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY INDICATES DEEP
CONVECTION CONTINUING TO WRAP INTO A RAGGED, CLOUD-FILLED 32-NM EYE
FEATURE. A 132151Z SSMIS 89 GHZ MICROWAVE IMAGE SHOWED DEEP, INTENSE
CONVECTION COMPLETELY ENCIRCLING THE EYE. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON DVORAK FIX LOCATIONS FROM ALL
AGENCIES AS WELL AS RADAR FIX DATA FROM JMA. THE INITIAL INTENSITY
IS SET AT 115 KNOTS BASED ON SUBJECTIVE DVORAK CURRENT INTENSITY
ESTIMATES OF T6.0 (115 KNOTS) FROM ALL REPORTING AGENCIES. TY 20W
LIKELY REACHED PEAK INTENSITY AROUND 2100Z, WHEN AN INTENSITY
ESTIMATE OF T6.5 (127 KNOTS) WAS REPORTED BY PGTW. TY 20W IS
CONTINUING TO DRIFT SLOWLY NORTHWARD IN A HIGHLY CONDUCIVE
ENVIRONMENT, WITH HIGH SEAS SURFACE TEMPERATURES AT OR ABOVE 31 DEG
CELSIUS, STRONG DUAL CHANNEL OUTFLOW, AND LOW (5-10 KNOTS) VERTICAL
WIND SHEAR (VWS), ENABLING ANOTHER PERIOD OF RAPID INTENSIFICATION
OVER THE PAST 12 HOURS. TY TALIM REMAINS TRAPPED IN A WEAK STEERING
ENVIRONMENT IN A COL AREA BETWEEN TWO SUBTROPICAL RIDGE (STR)
CENTERS, ONE OVER CHINA AND THE OTHER IN THE WESTERN PACIFIC AND AN
EXTENSION OF THE EASTERN STR LYING TO THE NORTH OF THE SYSTEM.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. OVER THE NEXT 24 HOURS, TY 20W WILL CONTINUE TO MEANDER
GENERALLY NORTHWARD UNDER WEAK STEERING FLOW FOR THE NEXT 12 HOURS.
BY TAU 24, THE NORTHERN RIDGE EXTENSION WILL WEAKEN AND MOVE
EASTWARDS, ALLOWING TY 20W TO BEGIN TO ROUND THE STR AXIS AND
ACCELERATE NORTHEASTWARDS. TY 20W IS EXPECTED TO MOVE NORTHEASTWARD
AT ABOUT 10 KNOTS, MAKING LANDFALL ALONG THE SOUTHERN PORTION OF
KYUSHU BEFORE TAU 72. THE LOW SHEAR, HIGH SSTS, AND DUAL CHANNEL
OUTFLOW ENVIRONMENT WILL ALLOW THE SYSTEM TO CONTINUE TO INTENSIFY,
PEAKING AT 120 KNOTS BY TAU 12. AFTER TAU 12, THE SYSTEM WILL REMAIN
STEADY FOR A SHORT PERIOD AS THE HINDERED EQUATORWARD OUTFLOW IS
OFFSET BY STRONGER POLEWARD OUTFLOW INTO THE DIVERGENT FLOW AHEAD OF
AN APPROACHING NEGATIVELY TILTED MID-LEVEL TROUGH. AFTER TAU 36, THE
SYSTEM WILL START TO WEAKEN AS VWS STARTS TO INCREASE BEYOND 40
KNOTS. DYNAMIC MODEL GUIDANCE IS IN VERY TIGHT AGREEMENT IN THE
TRACK THROUGH TAU 72.
   C. IN THE EXTENDED FORECAST, TY TALIM WILL ACCELERATE
NORTHEASTWARD AS IT BECOMES EMBEDDED IN A MID-LATITUDE TROUGH
APPROACHING FROM THE WEST. AS THE SYSTEM ADVECTS LARGE AMOUNTS OF
WARM AIR AT THE SURFACE, THE DOWNSTREAM RIDGE WILL BUILD, KEEPING TY
20W ON A TRACK WHICH WILL CROSS SOUTHERN HONSHU AND INTO THE SEA OF
JAPAN AFTER TAU 72, THEREAFTER CONTINUING OVER HOKKAIDO AND INTO THE
SOUTHERN SEA OF OKHOTSK BY TAU 120. THE SYSTEM WILL START TO BECOME
EXTRA-TROPICAL BY TAU 72 AND COMPLETE EXTRA-TROPICAL TRANSITION BY
TAU 120. TY 20W WILL CONTINUE TO WEAKEN AS IT CROSSES HONSHU AND
THEN HOKKAIDO DUE TO TERRAIN INTERACTION COMBINED WITH HIGH VWS AND
DECREASING SSTS. MODEL GUIDANCE IS IN VERY GOOD AGREEMENT ON THE
TRACK BEYOND TAU 72, BUT SHOWS SOME ALONG TRACK (SPEED) DIFFERENCES
DUE TO THE UNCERTAINTY ASSOCIATED WITH THE MID-LATITUDE TROUGH. WITH
THE STRONG AGREEMENT IN THE OVERALL TRACK THROUGH THE ENTIRE
FORECAST, THERE IS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST.//
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