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 839 
 WTPZ43 KNHC 262048 CCA
 TCDEP3
 
 TROPICAL STORM ROSLYN DISCUSSION NUMBER   6...CORRECTED
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP182016
 200 PM PDT MON SEP 26 2016
 
 CORRECTED STATUS AT 72H
 
 Although the center of Roslyn has become farther separated
 from the deep convection this afternoon due to strong
 southwesterly shear, recent ASCAT data indicate that the
 tropical cyclone is stronger than previously estimated.  The
 1756 UTC ASCAT overpass revealed 40-45 kt winds, and a much
 larger area of 34-kt winds than analyzed earlier.  Based on
 these data, the initial intensity has been set at 45 kt, and
 the 34-kt wind radii have been expanded accordingly.
 
 Increasing southwesterly vertical wind shear and gradually
 decreasing SSTs should cause weakening, but given the large size of
 the system the spindown process is likely to be more gradual than
 average.  In 24 to 36 hours, much cooler waters and a more stable
 airmass are expected to cause Roslyn to degenerate into a remnant
 low and to dissipate in 3 to 4 days.  The NHC intensity forecast has
 been adjusted upward in the early portion of the forecast to account
 for the higher initial intensity, but is unchanged thereafter.  The
 official forecast shows a slower rate of decay than the SHIPS
 guidance, but it is general agreement with the trend in the global
 models.
 
 Roslyn has not moved much during the past 24 hours, and the best
 estimate of the initial motion is 035/2 kt.  The models insist that
 Roslyn will begin moving northeastward within deep layer
 southwesterly flow between a mid-level ridge to the southeast and a
 large upper-level low over Baja California.  In a couple of days,
 the cyclone should turn northward, then northwestward once it
 weakens and is steered by the low-level flow.  The new NHC track is
 similar to the previous advisory and is near a consensus of the
 ECMWF and GFS models.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  26/2100Z 16.8N 118.8W   45 KT  50 MPH
  12H  27/0600Z 17.3N 118.4W   40 KT  45 MPH
  24H  27/1800Z 18.4N 117.7W   35 KT  40 MPH
  36H  28/0600Z 19.8N 117.3W   30 KT  35 MPH
  48H  28/1800Z 21.2N 117.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
  72H  29/1800Z 23.3N 118.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
  96H  30/1800Z...DISSIPATED
 
 $$
 Forecaster Brown
 
 
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