WDPN34 PGTW 271500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (NESAT) WARNING NR 
07//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 11W (NESAT), LOCATED APPROXIMATELY 415 NM NORTHEAST 
OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 06 KNOTS OVER 
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY 
DEPICTS FLARING CENTRAL CONVECTION BEING SHEARED TO THE SOUTHWEST 
AND A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THE 
INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON RECENT 
SATELLITE FIXES AND A LOW REFLECTIVITY CIRCULATION FEATURE OBSERVED 
IN A 271221Z 89GHZ AMSU-B IMAGE. THE INITIAL INTENSITY IS ASSESSED 
AT 55 KNOTS AND IS BASED ON DVORAK ESTIMATES FROM ALL AGENCIES 
REPORTING A CURRENT INTENSITY OF T3.5 (55 KNOTS). ENVIRONMENTAL 
CONDITIONS ARE CURRENTLY MARGINAL TO FAVORABLE AS ROBUST EQUATORWARD 
OUTFLOW IS PRESENT WITH MODERATE NORTHEASTERLY WIND SHEAR 
RESTRICTING POLEWARD OUTFLOW. SSTS ARE ALSO VERY CONDUCIVE FOR 
CYCLOGENESIS, AROUND 30 CELSIUS. CURRENTLY TS 11W IS TRACKING 
NORTHWESTWARD ALONG A WEAK MID TO LOW LEVEL SUBTROPICAL RIDGE TO THE 
EAST.           
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TS 11W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD AS 
ANOTHER RIDGE ANCHORED OVER THE EAST CHINA SEA ASSUMES STEERING. 
VERTICAL WIND SHEAR IS EXPECTED TO RELAX AND POLEWARD OUTFLOW IS 
EXPECTED TO IMPROVE OVER THE NEXT 36 HOURS ALLOWING TS 11W TO 
INTENSIFY INTO A TYPHOON REACHING A PEAK INTENSITY OF 80 KNOTS.  
BEYOND TAU 36 EASTERLY WIND SHEAR FROM THE STEERING RIDGE WILL BEGIN 
TO INCREASE, HELPING TO WEAKEN THE SYSTEM. LANDFALL OVER THE 
MOUNTAINOUS REGION OF TAIWAN WILL ALSO OCCUR AROUND TAU 48, FURTHER 
WEAKENING THE SYSTEM. 
   C. IN THE EXTENDED FORECAST PERIOD TS 11W WILL TRACK ACROSS 
TAIWAN AND REEMERGE OVER THE WARM WATERS OF THE TAIWAN STRAIT. THERE 
IS A SHORT WINDOW FOR TS 11W TO REORGANIZE AND INTENSIFY SLIGHTLY 
BEFORE MAKING LANDFALL AGAIN OVER CHINA. DURING THIS TIME THE 
STEERING RIDGE WILL REORIENT STEERING THE REMNANTS OF TS 11W 
NORTHWARD. TS 11W WILL DISSIPATE COMPLETELY WHILE OVERLAND CHINA. 
DYNAMIC MODEL GUIDANCE IS SHOWING MUCH BETTER AGREEMENT THAN ON 
PREVIOUS RUNS WITH THE OUTLIER FROM THE JAPANESE ENSEMBLE MEAN STILL 
SHOWING AN UNREALISTIC TURN NORTHWARD INTO THE STEERING RIDGE PRIOR 
TO MAKING LANDFALL OVER TAIWAN. DUE TO THE IMPROVEMENT IN MODEL 
TRACK GUIDANCE THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK.//
NNNN