WDPN31 PGTW 151500
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W (KULAP)
/WARNING NR 08//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 151200Z9 TO 191200Z3 JAN 2005.
   A. TROPICAL STORM (TS) 01W (KULAP), LOCATED APPROXIMATELY
300 NM SOUTH-SOUTHEAST OF GUAM, HAS TRACKED NORTHWARD AT 09
KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED
ON 151130Z1 ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING
INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES
OF 35 AND 45 KNOTS.
   B. TS 01W IS TRACKING NORTHWARD ALONG THE WESTERN PERI-
PHERY OF A LOW TO MID-LEVEL STEERING RIDGE ANCHORED TO THE
EAST. A LONG WAVE APPROACHING FROM THE WEST HAS CAUSED THE
STEERING RIDGE TO RETREAT EASTWARD AND REORIENT TO A MORE
MERIDIONAL PATTERN. TS 01W IS FORECAST TO CREST THE SUBTRO-
PICAL RIDGE AXIS BY TAU 36 AND THEN RECURVE TO THE NORTHEAST
AS IT INTERACTS WITH THE MID-LATITUDE WESTERLIES. THE AVAIL-
ABLE DYNAMIC AIDS CONSISTING OF NOGAPS, COAMPS, GFDN, NCEP
GFS, UKMET, JGSM, JTYM AND WBAR ARE IN FAIR AGREEMENT WITH
THIS SCENARIO THROUGH TAU 48. JGSM, UKMET AND JTYM DEPICT A
MERIDIONAL STEERING RIDGE RESULTING IN A MORE EASTWARD TRACK.
THIS FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE DYNAMIC
AIDS.
   C. TS 01W IS FORECAST TO CONTINUE INTENSIFYING IN A FAVOR-
ABLE ENVIRONMENT OF WEAK VERTICAL SHEAR AND GOOD POLEWARD OUT-
FLOW THROUGH TAU 36. AFTER THE SYSTEM CRESTS THE RIDGE AXIS,
IT WILL BEGIN TO WEAKEN AS IT INTERACTS WITH THE MID-LATITUDE
WESTERLIES.
   D. CURRENT WIND RADII ARE BASED ON A 150800Z4 TRMM IMAGE.
FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE
SIZED SYSTEM.
   E. THE EXTENDED FORECAST CALLS FOR TS 01W TO CONTINUE TRACK-
ING NORTHEASTWARD AND WEAKENING AS IT ENCOUNTERS INCREASED VER-
TICAL SHEAR FROM THE MID-LATITUDE WESTERLIES. UNCERTAINTY IN-
CREASES AFTER TAU 72 AS SOME OF THE MODELS WEAKEN THE SYSTEM
SIGNIFICANTLY; A PLAUSIBLE ALTERNATIVE IS FOR THE DEEP CON-
VECTION TO BECOME DECOUPLED FROM THE LOW LEVEL CIRCULATION CEN-
TER AND THE SYSTEM TO DISSIPATE OVER OPEN WATER.
3. FORECAST TEAM: BRAVO//

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