Marine Weather and Tide Forecast for Rapid City, SD

UPDATE
Issued at 926 PM MDT Sun May 24 2026

No big changes to the inherited forecast.

Still expecting a very warm day tomorrow with morning lows in the mid 40s to mid 50s and afternoon highs in the mid 80s to mid 90s.
Warmest temps will be in the SD plains with the cooler temps (but still above average) in NE WY. These warm temps will linger into Tuesday.

One change was to extend the timing of Monday's showers to more closely match what happened today. Hi-res models and the EURO ensemble support this.

Wind speeds through Monday morning look to be on the lighter side with slightly stronger winds, around 10 to 20 mph, in the afternoon. Monday night's winds will decrease in speed before really ramping up Tuesday. Tuesday's wind speeds could reach near 25 mph in the afternoon with gusts around 35 to 45 mph in W SD.
Speeds like that with temps in the 80s & 90s and RH down to around 20% could allow fire weather to creep back into the area.
Stay tuned.

DISCUSSION
(This Evening Through Sunday)
Issued at 1256 PM MDT Sun May 24 2026

Upper flow is transitioning this afternoon from WNW to near zonal.
Vis sat shows high based cu has developed across NE WY through the Black Hills. Still can't rule out an isolated shower or thunderstorm over the Hills late this afternoon, but most areas will remain dry.
Overnight advection will bring warmer temps to the area on Memorial Day. Highs will reach the upper 80s to lower 90s. Again, can't rule out an isolated afternoon shower or storm over the Hills, but otherwise quiet weather is expected. Models continue to show a deep, stationary upper low across in the vicinity of the Great Basin and northern California through the middle and latter part of this week.
Good moisture transport from the Gulf sets up over the central to northern Plains, bringing PWATs ranging from 125-175% of normal. The moisture will be available...it's just a matter of where the best forcing sets up. The ECM continues to focus on the Dakotas while the GFS targets WY, though there has been some shift eastward later in the week closer to the ECM. Will continue to monitor the trends.

AVIATION
(For the 12Z TAFS Through 12Z Tuesday Morning)
Issued At 446 AM MDT Mon May 25 2026

VFR conditions are expected through the forecast period. Isolated shra/TS may develop in/near Black Hills, but confidence in the storms reaching the TAF sites is very low.

UNR WATCHES/WARNINGS/ADVISORIES
SD...None.
WY...None.