Marine Weather and Tide Forecast for Hill City, SD

UPDATE
Issued at 957 PM MDT Thu Mar 19 2026

While winds have diminished this evening, humidity has been slow to recover - portions of NE WY and the southern Black Hills and foothills remain in the teens to around 25 percent.

Another critical fire weather day Friday with all of the ingredients in place: very warm (70s to mid 80s), dry (minimum RH bottoming out around 10 to 18 percent), breezy (west winds gusting 25 to 30 mph), and antecedent drought. While confidence in critical winds is lower from Pine Ridge through Martin, mixing heights in excess of 10k feet will allow for mixing of higher momentum air aloft with transient critical wind gusts.

Otherwise, little change with this forecast update. Extremely warm Saturday with 90s likely along and south of I-90. Cold front will bring chance of light rain, mainly for NW SD and the Black Hills overnight Saturday; precipitation amounts look meager (<0.1"). Mild and dry conditions quickly return late Sunday through at least the middle of next week with elevated fire weather conditions.

DISCUSSION
(This Afternoon Through Wednesday)
Issued at 1117 AM MDT Thu Mar 19 2026

Mean western CONUS ridge will continue to support unseasonably warm weather in much of the period through mid next week. A ridge topping impulse does cool things down Sunday and Monday, however things dry back out and warm up mid week as the ridge rebuilds.
Warm and dry westerly flow is ongoing across the area. Weak sfc trough will move through this afternoon and support a shift to NNW winds across portions of the area. However, no CAA associated with this feature. Thermal ridge will shift into the region Friday and Sat with the warmest day for most areas expected to be Sat, as long as the cold front does not speed up. If things remain on track, record high temps will likely be set the next two days at many locations including Rapid City where the all time March high (84) could be broken as highs are forecast to reach the low 90s.
Ridge topping impulse will move through Sat night with an associated cold front. This system may bring a few showers to the region Sat night into Sunday, esp across NW SD, but precip chances don't look great attm. Upper ridge then rebuilds mid next week with warm and dry weather returning before a significant cool down occurs toward the end of the week per a strong upper trough in westerly flow.

For further details on days 4 through 7 please visit weather.gov/wrh/TextProduct?product=PMDEPD

AVIATION
(For the 06Z TAFS Through 06Z Friday Night)
Issued At 1051 PM MDT Thu Mar 19 2026

VFR conditions are expected through the forecast period.

FIRE WEATHER
Issued At 1117 AM MDT Thu Mar 19 2026

Widespread critical fire weather conditions this afternoon.
Unseasonably warm highs in the 70s to low 80s, relative humidities as low as 10%, and breezy westerly winds will combine to create critical fire weather conditions. Lingering snow cover on the north and eastern slopes may mitigate fire risk in some spots in the northern Black Hills and Wyoming Black Hills.

Very warm, dry, and occasionally breezy conditions are expected to continue for the rest of this week. This will result in elevated to critical fire weather conditions each day. Slightly lower winds Friday may be a limiting factor most places, except far southwest areas, but winds increase again Saturday. Finally, a cold front will move through Sat afternoon, bringing breezy winds into the night period as well as cooler temperatures and higher humidities for a couple days. The combinations of low RH, frontal passage, and breezy winds may support red flag conds Sat for a large part of the area. Warm and dry weather returns for mid next week, however much colder weather looks to arrive toward the end of next week.

UNR WATCHES/WARNINGS/ADVISORIES
SD...Red Flag Warning from 10 AM to 9 PM MDT Friday for SDZ319>327- 329-331>333.
WY...Red Flag Warning from 10 AM to 9 PM MDT Friday for WYZ314>318.