WWUS20 KWNS 232155 SEL1 SPC WW 232155 NDZ000-240300- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 621 NWS Storm Prediction Center Norman OK 400 PM MDT Sun Aug 23 2026 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southwest North Dakota * Effective this Sunday afternoon and evening from 400 PM until 900 PM MDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Isolated significant damaging wind gusts to 75 mph possible SUMMARY...A few supercells with large hail up to 2 inches in diameter and isolated severe outflow gusts of 60-75 mph will be possible into this evening. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 55 miles north of Dickinson ND to 30 miles west of Lemmon SD. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 617...WW 618...WW 619...WW 620... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 32015. ...Thompson