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Real-time wind speeds, peak gusts, and surface chop forecasts from NOAA National Weather Service, verified public boat launches, USGS surface water telemetry, and South Dakota state boating regulations for Sylvan Lake (South Dakota).
Red Flag Warning issued October 9 at 12:12AM MDT until October 9 at 8:00PM MDT by NWS Rapid City SD
Peak Gusts: 6 mph. Light surface ripple; smooth navigation.
Cold Shock Hazard: Life jackets are strongly urged for all vessel occupants across open water.
Ramp Accessibility: Water level referenced at 6,145 ft MSL for launch ramp clearance across public access points.
Advisory Threshold: Official Lake Wind Advisories trigger when sustained winds reach 15 mph or waves exceed 3 ft.
Current index calculated from verified local atmospheric, hydrographic & alert inputs.
Fair for boating (73/100), from 4 available inputs. Supporting this: Gusts to 8 mph. Wind 8 mph from the southwest. Working against it: Active severe alert: Red Flag Warning. Not available from a verified source for this lake: visibility and conditions, verified water access. Confidence is moderate (84%) because some inputs are unavailable or older than ideal.
| Forecast Time | Wind (mph) | Gust (mph) | Direction | Surface Chop & Fetch | Watercraft Readiness |
|---|---|---|---|---|---|
| 5 AM | 8 mph | 8 mph | SW | Light surface ripple; gentle boat glide | Optimal |
| 6 AM | 9 mph | 21 mph | SW | Light surface ripple; gentle boat glide | Favorable |
| 7 AM | 9 mph | 22 mph | SW | Light surface ripple; gentle boat glide | Moderate |
| 8 AM | 8 mph | 23 mph | SW | Light surface ripple; gentle boat glide | Moderate |
| 9 AM | 8 mph | 23 mph | SW | Light surface ripple; gentle boat glide | Moderate |
| 10 AM | 9 mph | 24 mph | SW | Light surface ripple; gentle boat glide | Moderate |
| 11 AM | 10 mph | 25 mph | SW | Moderate chop (1–2 ft waves); steady navigation | Moderate |
| 12 PM | 13 mph | 25 mph | SW | Moderate chop (1–2 ft waves); steady navigation | Moderate |
| 1 PM | 13 mph | 25 mph | SW | Moderate chop (1–2 ft waves); steady navigation | Moderate |
| 2 PM | 14 mph | 28 mph | SW | Moderate chop (1–2 ft waves); steady navigation | Caution |
| 3 PM | 14 mph | 28 mph | SW | Moderate chop (1–2 ft waves); steady navigation | Caution |
| 4 PM | 13 mph | 27 mph | SW | Moderate chop (1–2 ft waves); steady navigation | Moderate |
| 5 PM | 8 mph | 22 mph | SW | Light surface ripple; gentle boat glide | Moderate |
| 6 PM | 8 mph | 20 mph | SW | Light surface ripple; gentle boat glide | Favorable |
| 7 PM | 10 mph | 21 mph | SW | Moderate chop (1–2 ft waves); steady navigation | Favorable |
| 8 PM | 9 mph | 22 mph | SW | Light surface ripple; gentle boat glide | Moderate |
| 9 PM | 10 mph | 22 mph | SW | Moderate chop (1–2 ft waves); steady navigation | Moderate |
| 10 PM | 12 mph | 24 mph | SW | Moderate chop (1–2 ft waves); steady navigation | Moderate |
Surface chop expands with sustained wind duration across Sylvan Lake's open water fetch. Early morning hours typically offer the calmest navigation before thermal afternoon winds develop.
Individual boat ramp GPS coordinates are currently being cataloged for Sylvan Lake. Public launches are managed by state, county, or local park authorities.
Ramp operational status and courtesy dock availability are subject to seasonal water level shifts and lake management authority guidelines.
Current index calculated from verified local atmospheric, hydrographic & alert inputs.
Good for kayaking (75/100), from 5 available inputs. Supporting this: Gusts to 8 mph. Wind 8 mph from the southwest. Working against it: Active severe alert: Red Flag Warning. Confidence is high (90%).