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TROPICAL DEPRESSION ROSLYN DISCUSSION NUMBER  13
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP182016
800 AM PDT WED SEP 28 2016

Roslyn has been weakening.  Deep convection associated with the
cyclone dissipated late yesterday, and only a few puffs of new
convection have redeveloped but are well removed to the northeast of
the center.  A TAFB Dvorak CI of 2.0 is used to lower the initial
intensity to 30 kt, and assumes some spin-down of the vortex since
the overnight ASCAT pass that showed 35-kt winds.  With
southwesterly shear of around 30 kt, increasing atmospheric
stability and an extremely dry environment, and much cooler waters
along the path of the cyclone, further weakening is likely.  Roslyn
is expected to degenerate into a remnant low later today, and the
current intensity forecast is in good agreement with the guidance.

The initial motion estimate is 035/09, though the shorter-term
motion may be a bit more to the left.  To the extent that Roslyn
remains a coupled cyclone, the motion should gradually turn
northward today around a cut-off low well southwest of the
California coast.  A turn toward the northwest is expected once the
cyclone become a shallower feature, and its motion is governed by
the low-level flow.  The track forecast is essentially an update of
the previous one and is close to a multi-model consensus without
the GFDL model.

FORECAST POSITIONS AND MAX WINDS

INIT  28/1500Z 21.0N 115.2W   30 KT  35 MPH
 12H  29/0000Z 21.9N 115.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 24H  29/1200Z 22.9N 116.1W   20 KT  25 MPH...POST-TROP/REMNT LOW
 36H  30/0000Z 23.4N 116.9W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  30/1200Z 23.6N 117.6W   15 KT  15 MPH...POST-TROP/REMNT LOW
 72H  01/1200Z...DISSIPATED

$$
Forecaster Kimberlain

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