Tropical Storm LAN Advisory Sun Oct 22

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 25W (LAN) WARNING NR 24//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON 25W (LAN), LOCATED APPROXIMATELY 337 NM SOUTHEAST
OF KADENA AB, HAS TRACKED NORTHEASTWARD AT 11 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 210553Z
89GHZ AMSU IMAGE DEPICTS DEEP CONVECTION SURROUNDING A 50NM EYE
FEATURE WITH WARMING CLOUD TOPS INDICATING THE START OF A WEAKENING
TREND. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
THE EVIDENT EYE FEATURE IN SATELLITE IMAGERY. UPPER-LEVEL ANALYSIS
SHOWS DUAL CHANNEL OUTFLOW WITH ENHANCED POLEWARD EXHAUST INTO THE
MID-LATITUDE WESTERLIES CURRENTLY OVER JAPAN. SSTS IN THE REGION ARE
STILL VERY WARM NEAR 29 CELSIUS, HOWEVER, STY 25W HAS TRACKED INTO
AN AREA OF SUBSTANTIALLY LOWER OCEANIC HEAT CONTENT. CURRENTLY STY
25W IS TRACKING POLEWARD ALONG THE WESTERN PERIPHERY OF THE DEEP
LAYERED SUBTROPICAL RIDGE.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. STY 25W WILL KEEP TRACKING POLEWARD ALONG THE CURRENT STEERING
RIDGE FOR THE DURATION OF THE FORECAST PERIOD. A SHORT-WAVE TROUGH
IS DEVELOPING JUST NORTHWEST OF THE SYSTEM, AND THE TROUGH WILL
BEGIN EXERTING INFLUENCE OVER THE POLEWARD OUTFLOW CHANNEL IN THE
NEXT 6 TO 12 HOURS PERPETUATING THE GRADUAL WEAKENING TREND.  AS THE
SYSTEM CONTINUES ON ITS NORTHWESTWARD TRACK, VERTICAL WIND WILL RISE
SUBSTANTIALLY AS IT APPROACHES THE WESTERLIES AND BEGINS INTERACTING
WITH THE BAROCLINIC REGION. STY 25W IS FORECAST TO BEGIN
EXTRATROPICAL TRANSITION SOMETIME BETWEEN TAU 24 AND 36 AS A FAIRLY
LARGE AND INTENSE SYSTEM. GALE FORCE WINDS ARE FORECAST TO EXTEND
FAR FROM THE SYSTEM CENTER REACHING WELL INTO THE SEA OF JAPAN
DESPITE TAKING A TRACK VERY CLOSE TO YOKOSUKA NAVAL STATION AND
SKIRTING THE EASTERN EDGE OF HONSHU. STY 25W WILL BEGIN TO EXHIBIT
FRONTAL CHARACTERISTICS SOMETIME AFTER TAU 96 COMPLETING ETT BY TAU
48. DYNAMIC MODEL GUIDANCE IS VERY GOOD AGREEMENT ON BOTH THE TRACK
AND SPEED OF THE SYSTEM, THUS LENDING HIGH CONFIDENCE IN THE
FORECAST TRACK.//
NNNN
NNNN