WDPN31 PGTW 181500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W (LINGLING) WARNING 
NR 03//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 01W (LINGLING), LOCATED APPROXIMATELY 383 NM EAST-
NORTHEAST OF ZAMBOANGA, PHILIPPINES, HAS TRACKED SOUTHEASTWARD AT 07 
KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE 
IMAGERY DEPICTS A FULLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) 
THAT HAS CONTINUED TO MOVE SOUTHEASTWARD IN A WEAK STEERING 
ENVIRONMENT AWAY FROM A STRONG NORTHEASTERLY SURGE. THE CURRENT 
POSITION IS BASED ON THE EXPOSED LLCC IN THE IR WITH GOOD 
CONFIDENCE. AN 180313Z SCATTEROMETRY PASS INDICATES A TIGHTLY 
CONSOLIDATED CIRCULATION WITH 35-40 KNOT WIND BARBS ALONG THE 
WESTERN SEMI-CIRCLE AND WEAKER 20-25 KNOT WIND BARBS ALONG THE 
EASTERN SEMI-CIRCLE. THE INITIAL INTENSITY OF 35 KNOTS IS BASED ON 
THE SCATTEROMETRY PASS AND DVORAK ESTIMATES RANGING FROM 30 TO 35 
KNOTS. UPPER-LEVEL ANALYSIS INDICATES TS 01W IS LOCATED IN A 
MARGINALLY FAVORABLE ENVIRONMENT WITH MODERATE TO STRONG (25 TO 30 
KNOTS) VERTICAL WIND SHEAR AND STRONG DIFFLUENCE ALOFT. THE SYSTEM 
IS CURRENTLY TRACKING SOUTHEASTWARD, AWAY FROM A STRONG 
NORTHEASTERLY SURGE EVENT, IN A WEAK STEERING ENVIRONMENT.
3. FORECAST REASONING.
   A. THE WEAK STEERING ENVIRONMENT HAS ALLOWED THE SYSTEM TO 
CONTINUE MOVING TO THE SOUTHEAST; HOWEVER DYNAMIC MODELS CONTINUE TO 
INDICATE A FORECAST TRACK BACK TO THE WEST-SOUTHWEST FOLLOWED BY 
DISSIPATION ACROSS MINDANAO. FOR THIS REASON THE JTWC FORECAST HAS 
BEEN EXTENDED OUT TO TAU 36 IN ORDER TO ACCOMMODATE FURTHER DRIFTING 
IN THE WEAK STEERING ENVIRONMENT PRIOR TO TRACKING WEST INTO 
MINDANAO.
   B. TS 01W IS FORECAST TO TURN SOUTHWESTWARD UNDER THE STEERING 
INFLUENCE OF THE DOMINANT NORTHEASTERLY SURGE. THE SYSTEM IS 
EXPECTED TO WEAKEN AND WILL DISSIPATE OVER LAND WITHIN THE NEXT 36 
HOURS. DYNAMIC MODELS REMAIN HIGHLY ERRATIC AND INCONSISTENT WITH A 
NUMBER OF MODELS INDICATING A QUASI-STATIONARY TRACK. THE JTWC 
FORECAST FAVORS THE GFS AND ECMWF SOLUTIONS, WHICH STEER THE SYSTEM 
OVER MINDANAO, PHILIPPINES. DUE TO THE WEAK STEERING ENVIRONMENT AND 
LARGE SPREAD IN THE MODEL TRACKERS, THERE IS LOW CONFIDENCE IN THE 
OFFICIAL FORECAST TRACK.//
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