WDPN31 PGTW 160300
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.//
NNNN