textproduct: Rapid City

KEY MESSAGES

- Daily chances for thunderstorms through early next week.

- Temperatures around or above normal expected through the forecast period.

DISCUSSION

(This Evening Through Friday) Issued at 149 PM MDT Fri Jul 18 2025

Current surface analysis shows low pressure centered over central SD, with frontal boundary running through south central SD into western NE and central WY. Upper models show zonal flow aloft. Temperatures currently sit in the upper 70s and 80s with relatively light northwest to northeast winds behind the boundary.

This afternoon, boundary wraps up into northeastern WY, providing an area of forcing amid a strong cap today. If storms are able to fire up, expected over northeastern WY down into southwestern SD late this afternoon or early evening. Modest shear but plenty of CAPE could support an organized severe storm or two if initiation is able to occur. Likely wont see any development outside of the immediate frontal zone. Threat today would be large hail and strong winds. Shortwave moving across the FA will support elevated showers/storms overnight, however no organized severe is expected.

Models show zonal to quasi-zonal flow persisting through the forecast period, with disturbances marking daily chances for storms over the area. While widespread severe is not expected, localized strong storms will remain a possibility over the weekend. Shortwave moves though at a better time Saturday to support isolated severe storm potential, coupled with 1000-2000 j/Kg ML CAPE and 30-40 kt 0-6km shear, if able to overcome the cap. May see potential for terrain driven upslope Black Hills development moving off into the plains. Similar set up for Sunday will support more isolated storm potential. Longer range models show little change in the overall pattern, keeping temperatures relatively steady, with daily (but limited) convective activity.

AVIATION

(For the 18Z TAFS Through 18Z Saturday) Issued At 1043 AM MDT Fri Jul 18 2025

Isolated thunderstorms around the Black Hills are expected this afternoon with scattered showers and thunderstorms across the entire area tonight. MVFR conditions are expected with the showers and storms as they move from west to east across the area. Over south central South Dakota, area of IFR vsby/cigs are likely after 06Z Saturday due to low clouds/fog.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.