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TROPICAL STORM ROSLYN DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP182016
200 PM PDT TUE SEP 27 2016

Roslyn remains a heavily sheared tropical cyclone.  Satellite
imagery shows that the cyclone's cloud pattern consists of a
plume-shaped burst of deep convection, with the low-level center
removed to the southwest of the convection due to 25 kt of
southwesterly shear.  Dvorak satellite classifications are unchanged
since earlier, T2.5 from SAB and T3.0 from TAFB.  Thus the initial
intensity remains 40 kt.

The vertical shear associated with a mid- to upper-tropospheric
cyclone over the northern Baja California peninsula is expected to
increase further over Roslyn during the next 24 hours.  In addition,
SSTs should gradually be decreasing along the cyclone's path while
Roslyn encounters a much drier and more stable air mass.  These
factors suggest that weakening should commence soon, and it could
occur rather quickly.  Remnant low status is now shown in 24 hours,
with dissipation by day 3.  The new NHC intensity forecast is a
little lower than the previous one, and just below the multi-model
consensus.

The initial motion estimate is 050/08.  Roslyn should turn
northward during the next 12 to 24 hours as it rotates around the
large circulation of the cutoff low retrograding into the
northeastern Pacific southwest of California.  Once the system is
sheared off in about 24 hours, the much shallower remnant low should
turn northwestward before dissipation.  The new track forecast has
been shifted some to the right and is close to a blend of the ECMWF
and GFS model solutions.

FORECAST POSITIONS AND MAX WINDS

INIT  27/2100Z 18.8N 116.6W   40 KT  45 MPH
 12H  28/0600Z 19.8N 116.3W   30 KT  35 MPH
 24H  28/1800Z 21.0N 116.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  29/0600Z 22.0N 117.1W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  29/1800Z 22.8N 118.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  30/1800Z...DISSIPATED

$$
Forecaster Kimberlain

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