WDPN31 PGTW 130300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (TOKAGE)
/WARNING NR 03//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 130000Z4 TO 180000Z9 OCT 2004.
   A. TROPICAL STORM (TS) 27W (TOKAGE), LOCATED APPROXIMATELY 80 NM
NORTHWEST OF GUAM, HAS TRACKED WESTWARD AT 16 KNOTS OVER THE PAST
06 HOURS. THE WARNING POSITION IS BASED ON 122330Z1 MULTISPECTRAL
SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE
CURRENT INTENSITY ESTIMATES OF 35 AND 45 KNOTS. RECENT ANIMATED
WATER VAPOR SATELLITE IMAGERY REVEALS TS 27W CONTINUES TO HAVE A
STRONG EQUATORWARD OUTFLOW, AND THE POLEWARD OUTFLOW IS STILL
DEVELOPING. A 122219Z7 TRMM PASS SHOWS A DISTINCT EYE, AND THE
STRONGEST CONVECTION IS SITUATED IN THE SOUTHWEST PERIPHERY OF THE
SYSTEM.
   B. TS 27W IS FORECAST TO REMAIN ON A WEST-NORTHWEST TRACK WHICH
SHOULD KEEP IT ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL
STEERING RIDGE. AS THE SYSTEM GAINS STRENGTH OVER THE NEXT 48 TO
72 HOURS, IT SHOULD BEGIN TO TRACK MORE NORTHWESTWARD DUE TO A
BREAKDOWN IN THE RIDGE AND INCREASED BETA EFFECT. A MAJOR SHORTWAVE
TROUGH IS EXPECTED TO BE OVER JAPAN BY TAU 72. THIS TROUGH SHOULD
PROVIDE ENOUGH WEAKNESS IN THE SUBTROPICAL RIDGE AXIS TO ALLOW THE
SYSTEM TO TRACK POLEWARD. THE AVAILABLE DYNAMIC AIDS CONSISTING OF
GFDN, NOGAPS, AVN, COAMPS, JGSM, AND JTYM ARE IN FAIR AGREEMENT
UNTIL TAU 24 AND POOR AGREEMENT FROM TAU 24 TO TAU 120. GFDN AND
NOGAPS RESOLVE A SOLUTION WHICH KEEPS TS 27W ON A WESTWARD TRACK
UNDER THE INFLUENCE OF THE STEERING RIDGE. JTYM AND JGSM RESOLVE
A MORE POLEWARD TRACK WITH JTYM BEING THE MOST EXTREME POLEWARD
OUTLIER. GIVEN THE RECENT STORM PERSISTENCE, THIS FORECAST IS
BASED ON A CONSENSUS OF ALL DYNAMIC AIDS WITH LESS EMPHASIS ON
JTYM.
   C. RECENT ANIMATED WATER VAPOR IMAGERY REVEALS AN INCREASE IN THE
OUTFLOW OF TS 27W. EQUATORWARD OUTFLOW IS VERY GOOD AT THIS TIME, AND
POLEWARD OUTFLOW IS IMPROVING. SINCE THE FORECAST TRACK SHOULD KEEP
TS 27W EQUATORWARD OF THE STEERING RIDGE THROUGH THE NEXT 72 HOURS,
AND NO SIGNIFICANT CHANGE IN THE OUTFLOW IS EXPECTED, THE SYSTEM IS
FORECAST TO INTENSIFY AT A CLIMATOLOGICAL RATE.
   D. CURRENT WIND RADII ARE BASED ON A 122108Z4 SSMI PASS. FORECAST
WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE TO LARGE SIZED
SYSTEM.
   E. DURING TAU 96 AND 120, THE STEERING RIDGE SHOULD CONTINUE TO
BREAK DOWN WHICH WILL ALLOW TS 27W TO MAINTAIN THE POLEWARD TRACK.
AS THE MAJOR SHORTWAVE TROUGH CONTINUES TO MIGRATE EASTWARD, THE
POLEWARD OUTFLOW SHOULD INCREASE, AND THE SYSTEM IS EXPECTED TO HAVE
PEAK INTENSITY AT TAU 120.
3. FORECAST TEAM: LEFFLER/JACOBS/CHRISTIAN/LEWIN//

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