Tropical Storm TALIM Advisory pt., 15.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (TALIM) WARNING NR 26//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 20W (TALIM), LOCATED APPROXIMATELY 193 NM WEST-NORTHWEST
OF KADENA AB, HAS TRACKED NORTH-NORTHEASTWARD AT 03 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY INDICATES
THAT THE LOW LEVEL CIRCULATION CENTER (LLCC) HAS STARTED TO DECOUPLE
FROM THE UPPER LEVEL ROTATION. THOUGH THERE ARE HINTS OF ANOTHER EYE
DEVELOPING, THE LLCC IS OFFSET TO THE SOUTH FROM THIS NEW EYE
FEATURE. 142230Z SSMIS 37 GHZ AND 89 GHZ MICROWAVE IMAGERY SUPPORTS
THIS PREMISE, WITH THE ASSESSED CENTERS BEING APPROXIMATELY 10 NM
APART. AVAILABLE IMAGERY CONTINUES TO SHOW LITTLE IN THE WAY OF
CONVECTION, WITH A WEAK BAND STARTING TO FORM AROUND THE SOUTHERN
EDGE OF THE NEW EYE, BUT OTHERWISE CONFINED TO THE NORTHEAST
QUADRANT. THE INITIAL POSITION IS PLACED WITH MODERATE CONFIDENCE
BASED ON SATELLITE FIXES FROM PGTW AND RJTD. THE INITIAL INTENSITY
IS ASSESSED AT 80 KNOTS AND IS A BLEND BETWEEN A PGTW DVORAK CURRENT
INTENSITY ESTIMATE OF T5.0 (90 KNOTS), AN AUTOMATED DVORAK TECHNIQUE
(ADT) OF T4.3 (73 KNOTS) AND SATCON OF 69 KNOTS AT 0000Z. TY 20W IS
NOW MOVING TO THE NORTHEAST AROUND 5 KNOTS, INDICATING THAT IT HAS
ROUNDED AXIS OF THE SUBTROPICAL RIDGE (STR) AND SHOULD NOW START TO
ACCELERATE TOWARDS THE NORTHEAST AHEAD OF AN APPROACHING MID-
LATITUDE TROUGH AND ALONG THE WESTERN PERIPHERY OF THE STR TO THE
EAST. UPPER-LEVEL ANALYSIS INDICATES THE SYSTEM RESIDES IN AN
OVERALL FAVORABLE ENVIRONMENT, WITH MODERATE VERTICAL WIND SHEAR
(VWS), AND STRONG POLEWARD OUTFLOW. THESE FAVORABLE FACTORS ARE
HOWEVER BEING OFFSET BY THE UPWELLING OF SIGNIFICANTLY COOLER WATERS
AND THE LOSS OF THE EQUATORWARD OUTFLOW CHANNEL.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 20W WILL BEGIN TO ACCELERATE NORTHEASTWARD AHEAD OF A
DEVELOPING MID-LATITUDE TROUGH, REMAINING ON A GENERALLY
NORTHEASTWARD TRACK THROUGH TAU 72. THE SYSTEM IS EXPECTED TO
UNDERGO ADDITIONAL WEAKENING THROUGH TAU 12, AS IT CONTINUES TO MOVE
SLOWLY OVER WATERS WHICH HAVE COOLED DUE TO UPWELLING. FROM TAU 12
TO 24, TY 20W WILL MAINTAIN INTENSITY AT 75 KNOTS, BEFORE SHEAR
INCREASES BEYOND 30 KNOTS, AND WHILE TRANSITING OVER A DEEPER POOL
OF WARM WATER. THROUGH TAU 48 HOWEVER, VWS WILL BEGIN TO DRASTICALLY
INCREASE, LEADING TO A SLOW WEAKENING OF THE SYSTEM BEFORE IT MAKES
LANDFALL OVER SOUTHERN KYUSHU BY TAU 48. AFTER LANDFALL, TY 20W WILL
RAPIDLY MOVE ACROSS SOUTHERN HONSHU AND INTO THE EAST SEA OF JAPAN
BY TAU 72. THE SYSTEM WILL BEGIN EXTRATROPICAL TRANSITION PRIOR TO
TAU 72 AS IT ENCOUNTERS BAROCLINIC FLOW ASSOCIATED WITH A NEGATIVELY
TILTED MID-LATITUDE TROUGH. NUMERICAL MODEL GUIDANCE IS IN GOOD
AGREEMENT THROUGHOUT THIS PORTION OF THE FORECAST, LENDING HIGH
CONFIDENCE TO THE JTWC OFFICIAL FORECAST TRACK THROUGH TAU 72.
   C. DURING THE EXTENDED FORECAST PERIOD, TY 20W WILL RAPIDLY
TRANSIT NORTHEASTWARD AS IT BECOMES FULLY EMBEDDED IN THE
AFOREMENTIONED MID-LATITUDE TROUGH. EXTRATROPICAL TRANSITION IS
EXPECTED TO BE COMPLETE BY TAU 96. FAVORABLE BAROCLINIC SUPPORT FROM
THE MID-LATITUDE TROUGH WILL ALLOW THE SYSTEM TO BECOME AN INTENSE
EXTRATROPICAL LOW WITH EXTENSIVE GALE FORCE WINDS, AS REFLECTED IN
THE CURRENT FORECAST. NUMERICAL MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT THROUGH THE EXTENDED FORECAST PERIOD, LENDING HIGH
CONFIDENCE TO THE JTWC OFFICIAL FORECAST TRACK.//
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