WDPN34 PGTW 281500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (NESAT) WARNING NR 
11//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON 11W (NESAT), LOCATED APPROXIMATELY 278 NM SOUTHEAST OF
TAIPEI, TAIWAN, HAS TRACKED NORTHWESTWARD AT 11 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS 
DEEP CENTRAL CONVECTION AND IMPROVED ORGANIZATION OVER THE LAST SIX 
HOURS. THERE IS HIGH CONFIDENCE IN THE INITIAL POSITION WHICH IS 
BASED ON RECENT SATELLITE FIXES AND A PINHOLE EYE FEATURE OBSERVED 
IN A 280943Z 37 GHZ WINDSAT IMAGE. THE INITIAL INTENSITY ASSESSMENT 
OF 70 KNOTS IS BASED ON MULTI-AGENCY DVORAK ESTIMATES RANGING FROM 
T4.0 TO T4.5 (65 TO 77 KNOTS). WHILE UPPER-LEVEL OUTFLOW HAS 
IMPROVED SOME IN THE POLEWARD DIRECTION THERE IS STILL NORTHEASTERLY 
WINDS ASSOCIATED WITH THE NORTHERN RIDGE. DESPITE THIS, VERTICAL 
WIND SHEAR HAS REMAINED FAVORABLE. COMPETING OUTFLOW WITH TD 12W 
ABOUT 550 NM TO THE WEST WILL ALSO RESTRICT SOME OUTFLOW ON THE 
WESTERN SIDE. SSTS ARE CURRENTLY AROUND 30 CELSIUS AND CONDUCIVE FOR 
INTENSIFICATION. TY 11W IS TRACKING NORTHWESTWARD ALONG A BUILDING 
SUBTROPICAL RIDGE ANCHORED OVER THE EAST CHINA SEA.           
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TY 11W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD GUIDED 
BY THE NORTHERN STEERING RIDGE. EASTERLY VWS IS EXPECTED TO BE 
MINIMAL BUT GRADUALLY STRENGTHEN AS THE SYSTEM TRACKS NORTHWARD DUE 
TO THE STRONG UPPER-LEVEL RIDGE SETTING UP TO THE NORTH. THE 
DOMINANT WIND FLOW WILL RESTRICT POLEWARD OUTFLOW, BUT EQUATORWARD 
EXHAUST SHOULD REMAIN FAIRLY ROBUST. SSTS IN THE REGION WILL ALSO 
REMAIN VERY FAVORABLE AND TY 11W IS EXPECTED TO INTENSIFY OVER THE 
NEXT 12 HOURS REACHING A PEAK INTENSITY OF 80 KNOTS BEFORE VWS 
STARTS TO DOMINATE AND LANDFALL OCCURS OVER CENTRAL TAIWAN. TY 11W 
WILL SLOW DOWN AND WEAKEN SIGNIFICANTLY AS IT TRACKS OVER THE 
MOUNTAINOUS TERRAIN. TY 11W WILL REEMERGE OVER THE WARM OPEN WATER 
OF THE TAIWAN STRAIT WITH A BRIEF PERIOD TO REORGANIZE BEFORE MAKING 
LANDFALL AGAIN OVER CHINA AROUND TAU 42. EASTERLY WIND SHEAR IS 
EXPECTED TO PERSIST AND INFLUENCE THE ABILITY AND DEGREE TY 11W WILL 
REINTENSIFY. SIMULTANEOUSLY TD 12W WILL APPROACH TY 11W FROM THE 
SOUTH AND MERGE SOMETIME BETWEEN TAU 48 AND 72. THE STEERING RIDGE 
WILL ALSO REORIENT ITSELF TO A NORTH SOUTH AXIS DURING THIS TIME 
CAUSING TY 11W TO TURN NORTHWARD WHILE OVER LAND IN CHINA. DYNAMIC 
MODEL GUIDANCE SHOWS VERY GOOD AGREEMENT WITH THE FORECAST, HOWEVER 
THERE IS INCREASING UNCERTAINTY IN THE EXTENDED TAUS AS THE SYSTEM 
WEAKENS, TRACKS OVER LAND, AND MERGES WITH 12W. OVERALL THERE IS 
HIGH CONFIDENCE IN THE FORECAST TRACK.//
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