WDPN31 PGTW 251500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W WARNING NR 09//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TYPHOON (TY) 20W (NESAT), LOCATED APPROXIMATELY 410 NM EAST OF
MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 08 KNOTS OVER THE PAST
SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES A RAPIDLY 
CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH TIGHTLY-
CURVED BANDING WRAPPING INTO A WELL-DEFINED CENTER. A 251105Z SSMIS 
37 GHZ IMAGE DEPICTS A MICROWAVE EYE FEATURE WITH A STRONG BANDING 
FEATURE WRAPPING FROM THE NORTHWEST QUADRANT INTO THE SOUTH 
QUADRANT. ANIMATED WATER VAPOR IMAGERY SHOWS EXCELLENT RADIAL 
OUTFLOW. THE CURRENT POSITION IS BASED ON THE SSMIS IMAGE AND PGTW 
FIX WITH GOOD CONFIDENCE. THE CURRENT INTENSITY WAS ASSESSED AT 70 
KNOTS, SLIGHTLY HIGHER THAN THE SUBJECTIVE DVORAK ESTIMATES OF 65 
KNOTS, BASED ON AN OBJECTIVE INTENSITY ESTIMATE OF 71 KNOTS.
3. FORECAST REASONING.
   A. NO CHANGE TO FORECAST PHILOSOPHY.
   B. TY 20W IS FORECAST TO TRACK WESTWARD TO WEST-NORTHWESTWARD 
THROUGH TAU 72 UNDER THE STEERING INFLUENCE OF THE DEEP SUBTROPICAL 
RIDGE POSITIONED NORTH OF THE SYSTEM. MODEL GUIDANCE IS IN TIGHT 
AGREEMENT THROUGH TAU 72, THEREFORE, THE JTWC FORECAST IS POSITIONED 
CLOSE TO THE MODEL CONSENSUS. TY 20W IS STILL EXPECTED TO RAPIDLY 
INTENSIFY PRIOR TO MAKING LANDFALL OVER LUZON AND SHOULD REACH A 
PEAK INTENSITY BETWEEN 115-130 KNOTS BY TAU 36. TY 20W WILL WEAKEN 
AS IT CROSSES LUZON BUT SHOULD RE-STRENGTHEN SLIGHTLY OVER THE SOUTH 
CHINA SEA. 
  C. IN THE EXTENDED TAUS, TY 20W WILL CONTINUE TRACKING WEST-
NORTHWESTWARD TOWARD HAINAN ISLAND UNDER THE STEERING INFLUENCE OF 
THE SUBTROPICAL STEERING RIDGE BUILDING INTO SOUTHEAST CHINA. THE 
DYNAMIC MODELS HAVE COME INTO BETTER AGREEMENT WITH A 350 NM SPREAD 
IN TAU 120 POSITIONS. GFS AND NOGAPS REMAIN THE NORTHERN OUTLIERS 
WITH TRACKS NEAR HONG KONG AND APPEAR UNLIKELY AS THEY TRACK THE 
SYSTEM INTO THE RIDGE. THE REMAINDER OF THE GUIDANCE (UKMO, GFDN, 
ECMWF) IS TIGHTLY CLUSTERED OVER HAINAN ISLAND AND REPRESENTS A MORE 
LIKELY SCENARIO. THE JTWC FORECAST IS POSITIONED SLIGHTLY FASTER AND 
TO THE SOUTH OF THE TAU 96/120 MODEL CONSENSUS FORECASTS.//
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