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TROPICAL STORM ROSLYN DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182016
800 AM PDT TUE SEP 27 2016
Roslyn continues to be affected by strong southwesterly shear, with
the center of the tropical cyclone exposed to the southwest of the
associated deep convection. The initial intensity remains 40 kt
for this advisory, which is an average of Dvorak estimates of
45 kt and 35 kt, from TAFB and SAB, respectively. Roslyn should
slowly weaken due to increasing southwesterly shear, gradually
decreasing SSTs, and dry mid-level air that is wrapping around
the western portion of the circulation. The updated NHC
intensity forecast is unchanged from the previous advisory and
calls for Roslyn to become a remnant low in 36 hours, and
dissipate in 3 to 4 days.
Recent satellite fixes indicate that Roslyn is moving northeastward
or 045/7 kt. The tropical storm is forecast to turn northward by
tonight around the eastern portion of a mid- to upper-level trough
extending southwestward from a large cut-off low over northwestern
Mexico. By late Wednesday, a weaker and more vertically shallow
Roslyn is expected to turn northwestward. There is more spread in
the track models this morning, but little change was required
to the NHC forecast which is located near the middle of the guidance
envelope.
FORECAST POSITIONS AND MAX WINDS
INIT 27/1500Z 18.3N 117.3W 40 KT 45 MPH
12H 28/0000Z 19.3N 116.9W 35 KT 40 MPH
24H 28/1200Z 20.6N 116.7W 30 KT 35 MPH
36H 29/0000Z 21.8N 117.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 29/1200Z 22.6N 118.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 30/1200Z 23.5N 120.0W 15 KT 15 MPH...POST-TROP/REMNT LOW
96H 01/1200Z...DISSIPATED
$$
Forecaster Brown
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