Marine Weather and Tide Forecast for Hill City, SD

DISCUSSION
(This Evening Through Friday)
Issued at 1223 PM MST Fri Dec 12 2025

Massive western CONUS ridge will drive the weather in the period as the active northern stream continues to alter its northern extent. Arctic front stalled over the region today, with rounds of FGEN snow continuing. Another impulse is will shift the main FGEN area back north with weak WAA aloft. This will support a round of light to moderate snow across northwest into central SD tonight into Sat morning. Still expect low end adv snow there, with perhaps a slight downtrend in amounts compared to previous model runs. Expect cold temps tonight with lows below zero across NW SD, warmer to the southwest. Frontal boundary will shift back south Sat, as weak CAA ensues behind the impulse. Some lingering clouds and flurries will be possible across the SW half Sat afternoon.
Temps will drop off Sat night most places, esp the SD Plains where subzero temps can be expected. However, WAA will ensue Sat night across western areas with temps starting to rise, esp in the BH.
WAA will ramp up Sun as breezy SW winds develop across northeast WY and the BH, and foothills by afternoon. H85 temps are progged to warm to 20C by afternoon, which will support aggressive warming, esp in the BH and foothills where 60s are forecast for highs. Warm air will spread east with mild and dry weather expected through mid week. However, the active northern stream will force the frontal boundary back south later in the week, with a roller coaster setup ensuing as several stronger shortwaves progress through semi-westerly flow.

AVIATION
(For the 06Z TAFS Through 06Z Saturday Night)
Issued At 1012 PM MST Fri Dec 12 2025

Widespread MVFR and areas IFR conditions due to low clouds/snow will continue through 13/17-19z. Transient LIFR conditions will occur in the moderate snow bands, mainly over northwestern SD.
After 13/18z, slow improvement is expected to VFR conditions across the forecast area after 13/21-23z.

UNR WATCHES/WARNINGS/ADVISORIES
SD...Winter Weather Advisory until 8 AM MST Saturday for SDZ001-002- 013-014-032-078.
WY...None.