textproduct: Bismarck

KEY MESSAGES

- Low to medium chances (20 to 40 percent) for thunderstorms remain this evening through. Some may become severe over western and south central North Dakota with hail to the size of golf balls and winds to 70 mph the main threats. - Daily chances for showers and thunderstorms continue through the upcoming work week. Isolated strong to severe storm is possible across the south Monday and Tuesday.

- Near to a bit below average temperatures through the first part of the week, then a cooling trend for the later part of the week.

- Wildfire smoke aloft could continue into mid week, with patchy smoke mixing down to the surface at times.

UPDATE

Issued at 942 PM CDT Sun Aug 9 2026

Instability has decreased across the region, thus convection has trended down. No major updates needed at this time.

UPDATE Issued at 611 PM CDT Sun Aug 9 2026

Remnants of an MCS up in southern Saskatchewan continues to churn and move eastward kicking off some convection along the International Border. Decent shear will sustain storms, but the lack in instability could prevent storms from becoming strong to severe. Daytime heating continues to diminish reducing instability across the region. The new CAMs model runs do bring some of those storms across the northwest, due to the elevated shear sustain them, however the previous CAMs run did not have storms making it very far across the northwest. So confidence remains low on whether the storms will sustain themselves and increase in strength. No updates are needed to the forecast at this time as the forecast remains on track.

DISCUSSION

Issued at 245 PM CDT Sun Aug 9 2026

Currently there is the remnants of an MCS in southern Canada moving eastward. Meanwhile, weak elevated showers are starting to form across a stalled boundary in the south. The noon SPC update has trimmed the Slight Risk somewhat across the area as this morning's CAMs have not been as aggressive with thunderstorm development this afternoon and evening. Previous CAMs had the Canadian MCS being the nudge for convection in the north later this afternoon, with thunderstorms then pushing east and southward through the evening. This MCS may be a touch further north than previous forecast which could limit this scenario from playing out. Additionally, lower CAPE values in the north are being observed yet strong shear is still in place. If a thunderstorm can develop in the north, skinny CAPE profiles will limit the severe threat despite higher amounts a shear. If these northern storms can develop late this afternoon, then monitoring their progressing south and eastward will be worthwhile as they enter into a more unstable area with modest to high shear. If this MCS does not kick off convection this afternoon, then the area will have to wait for the associated mid level wave to move through this evening and possibly tonight and interact with the mentioned stalled boundary. There is high uncertainty this wave would be enough to overcome some capping in place. Thus the severe threat at least through this evening remains conditional and will have to continue to monitor. There still remains enough shear and decent hodographs for rotating cells this evening, thus kept the hazards the same for messaging. Tonight, elevated instability continues to increase while shear remains modest to high. The stalled boundary may get pushed slightly eastward as the mentioned mid level wave move through. This could bring some isolated to scattered showers and thunderstorms as a result. CAPE profiles are somewhat skinny, although high amounts of shear could bring some isolated severe hail through the night. High DCAPE and 0 to 3 KM shear could also keep the 70 mph wind threat through the night. This still remains dependent on enough lift to initiate thunderstorms, which remains uncertain at this time. Otherwise look for lows tonight in the 50s.

Monday and Tuesday are similar weather days as the west northwest flow aloft remains along with the mentioned stall frontal boundary as well as an inverted surface trough in the west. The result will be similar, near normal, temperatures each day in the mid 70s to mid 80s and lows in the 50s. Depending on timing of weak waves in this flow combined with instability along the stalled boundary, near daily chances for showers and thunderstorms are possible each day. SPC also showing an isolated severe thunderstorm risk across the south each day mainly where the better instability and shear line up. Damaging winds and large hail will be the main threat with any isolated thunderstorms to start the week. Westerly flow aloft could also linger wildfire smoke aloft early to at least mid week. Patchy smoke at the surface may be found during the day as a result.

Mid to late week, the trend remains for a cooling trend with continued near daily chances for showers and thunderstorms. Some model runs bringing increased precipitation across the area with these shower and thunderstorm chances. This could stem from increased PWAT values as a surface low in the central plains attempts to bring increased gulf moisture. Meanwhile the flow aloft could switch to southwest, bringing a more unsettled pattern. The concerns with this are some clusters showing the moisture gets cut off to our south and/or the unsettled southwest flow pattern does not fully materialize. This would bring a less active forecast and perhaps not as much of a cool down. Something to monitor going forward. Either way this pattern would also bring less fire weather concerns for the upcoming week given increased RH values, cooler temperatures, light winds, and chances for precipitation.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 611 PM CDT Sun Aug 9 2026

Thunderstorms could move in from Canada into the northwest this evening, but there is low confidence in location and strength. FU could settle to the surface and produce decrease visibility tonight, amendments will be made if visibility reductions do occur. Winds will remain light and variable tonight veering to easterly tomorrow morning.

BIS WATCHES/WARNINGS/ADVISORIES

None.