Tropical Storm KOPPU Advisory Fr, 16.10.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (KOPPU) WARNING NR 13//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 24W (KOPPU), LOCATED APPROXIMATELY 370 NM EAST OF
MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 07 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) CONTINUES
TO SHOW DEEPENED CONVECTIVE BANDING OBSCURING THE LOW-LEVEL
CIRCULATION CENTER. THE CURRENT POSITION IS BASED ON THE MSI AND
SATELLITE FIXES FROM PGTW AND RJTD WITH GOOD CONFIDENCE. THE INITIAL
INTENSITY OF 80 KNOTS IS BASED ON THE CURRENT STRUCTURE AND
CORRESPONDING DVORAK INTENSITY ESTIMATES OF T4.5 (77 KNOTS) FROM
PGTW AND RJTD. UPPER-LEVEL ANALYSIS INDICATES TY 24W REMAINS IN A
FAVORABLE ENVIRONMENT WITH LOW VERTICAL WIND SHEAR AND RADIAL
OUTFLOW AS EVIDENT OF THE WATER VAPOR IMAGERY. TY 24W IS TRACKING
ALONG THE SOUTHERN PERIPHERY OF THE DEEP-LAYERED STR EXTENSION, WITH
THE STR ANCHORED FAR TO THE NORTHEAST.
3. FORECAST REASONING.
   A. NO CHANGE TO FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC
REASONING MESSAGE. HOWEVER, DUE TO SIGNIFICANT SPREAD AMONG
AVAILABLE TRACKERS, THERE IS A CHANGE IN FORECAST TRACK IN THE
EXTENDED TAUS.  SEE PARAGRAPH 3.C. FOR DETAILS.
   B. TY KOPPU WILL CONTINUE TO TRACK WESTWARD THROUGH TAU 48 ALONG
THE SOUTHERN PERIPHERY OF THE STEERING STR EXTENSION. UPPER-LEVEL
AND ENVIRONMENT CONDITIONS WILL CONTINUE TO IMPROVE, LEADING TO
RAPID INTENSIFICATION OVER THE NEXT 36 HOURS WITH A PEAK INTENSITY
OF 115 KNOTS BY TAU 36. BEYOND THAT, THE SYSTEM WILL MAKE LANDFALL
AND BEGIN DECAYING OVER LUZON.
   C. BEYOND TAU 72, TY 24W WILL SLOW AND TURN POLEWARD DUE TO A
SLIGHT BREAK IN THE STR. ADDITIONALLY, THE TERRAIN OF LUZON WILL
CONTINUE TO DECAY THE SYSTEM THROUGH THE REMAINDER OF THE FORECAST
PERIOD AS IT RE-EMERGES INTO THE LUZON STRAIT. MODEL GUIDANCE
REMAINS IN TIGHT AGREEMENT THROUGH TAU 48, BUT CONTINUES TO SHOW
SIGNIFICANT SPREAD AFTER TAU 48. DUE TO THE UNCERTAINTY IN THE STORM
MOTION AND DISPARITY AMONG AVAILABLE TRACKERS IN THE EXTENDED TAUS,
THE JTWC TRACK FORECAST CONFIDENCE LEVEL REMAINS LOW.//
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