UNCLAS//N03144//
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W (YANYAN) WARNING NR 
18//
RMKS/
WDPN31 PGTW 200300
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 200000Z2 TO 230000Z5 JAN 03.
   A. TROPICAL STORM (TS) 01W (YANYAN), LOCATED APPROXIMATELY 366 NM 
EAST-NORTHEAST OF SAIPAN, HAS TRACKED NORTHEASTWARD AT 12 KNOTS OVER 
THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 192330Z8 VISIBLE 
AND ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS 
BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 35, 45, AND 55 
KNOTS AND A 191958Z3 QUIKSCAT PASS. ANIMATED MULTISPECTRAL IMAGERY 
DEPICTS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER SOUTHWEST 
OF THE DEEP CONVECTION. 
   B. TS 01W IS FORECAST TO TRACK NORTHEASTWARD THROUGH THE PERIOD 
UNDER THE INFLUENCE OF A LOW TO MID-LEVEL SUBTROPICAL RIDGE TO THE 
EAST. A MID-LATITUDE SYSTEM EAST OF JAPAN IS EXPECTED TO PROPAGATE 
EASTWARD AND ENHANCE THE NORTHEAST MOVEMENT OF THE SYSTEM. THE 
AVAILABLE DYNAMIC AIDS, CONSISTING OF NOGAPS, GFDN, THE JAPANESE 
GLOBAL SPECTRAL (JGSM) AND TYPHOON (JTYM) MODELS, UKMET GLOBAL 
SPECTRAL MODEL (EGRR), NCEP AVIATION (AVN), COAMPS, AFWA MM5, 
TCLAPS, AND TLAPS MODELS, ARE IN FAIR AGREEMENT THROUGH 48 HOURS.
TCLAPS AND UKMET INDICATE SOME INTERACTION WITH THE APPROACHING MID-
LATITUDE SYSTEM, RESULTING IN A MORE POLEWARD TRACK. OUR FORECAST IS 
BASED ON PERSISTENCE AND ALL AVAILABLE DYNAMIC AIDS.
   C. TS 01W IS EXPECTED TO WEAKEN AS IT TRACKS NORTH OF THE UPPER 
LEVEL RIDGE AXIS INTO INCREASING VERTICAL SHEAR. 
   D. INITIAL WIND RADII ARE BASED ON A 191958Z3 QUIKSCAT PASS. 
FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE-SIZED 
SYSTEM.
FORECAST TEAM: WINGEART/GRUBER/LAM/STATEN/KUMAGA//
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