textproduct: Bismarck

KEY MESSAGES

- Showers and thunderstorms will push across the state from west to east tonight. A strong thunderstorm is possible.

- Scattered showers and isolated thunderstorms are possible Tuesday, mainly in the north and east.

- Low chances for showers and thunderstorms Wednesday and Thursday, with increasing chances Friday and through the into weekend.

UPDATE

Issued at 106 AM CDT Tue Jun 23 2026

The forecast for tonight remains on track. Made some minor adjustments to POPs and sped up the decrease in sky cover west. Best shear remains south, where a strong thunderstorm remains possible. Updated the HWO to reflect this.

UPDATE Issued at 958 PM CDT Mon Jun 22 2026

Convection in north central ND has had its intensity decrease the last 60-90 minutes as boundary layer cooling and expanding outflow both combine to reduce already-weak bouyancy. Upstream showers and thunderstorms have rapidly entered southwestern ND on a pace somewhat ahead of earlier expectations. Wind fields aloft are increasing aloft as expected, but midlevel lapse rates and CAPE remain weak, so the severe-storm risk remains low. We will nonetheless continue to mention the possibility of a strong storm overnight in respect to the increasing winds aloft and to some recent HRRR simulations that similarly show a few stronger storms as the main area of showers and storms moves eastward.

UPDATE Issued at 709 PM CDT Mon Jun 22 2026

Thunderstorms in north central and parts of northwest ND from near Westhope to Kenmare, Stanley, and Watford City have and continue to regenerate near a broad surface frontal zone. The environment is characterized by weak bouyancy and weak deep- layer shear, though sufficient low-level CAPE and vorticity have contributed to occasional updraft intensification in that area. This has resulted in small hail with the more intense cells, and slow storm motions and a relatively-moist vertical profile have and will continue to contribute to locally heavy rainfall. A low landspout tornado risk continues, but is apt to decrease in the next few hours as convection becomes more widespread and continues to disrupt the pre-existing horizontal vorticity along the surface boundary.

Otherwise, strong forcing for ascent tied to the upstream short wave trough and related jet streak aloft is beginning to move into eastern MT, resulting in an increase of showers and storms. That activity is expected to move into southwestern ND by late evening, and concurrently increasing wind fields aloft support a marginal severe-storm risk in southwestern ND. Weak bouyancy will still be a limiting factor. Otherwise, both the convection currently in north central ND and activity expanding into southwestern ND by late evening is expected to gradually move eastward and merge overnight as the stronger shortwave trough crosses the area. The forecast has this well-advertised, so only minor changes were needed with this update cycle.

DISCUSSION

Issued at 236 PM CDT Mon Jun 22 2026

Daily chances for showers and thunderstorms this week with a low probability for severe storms. Better chances for thunderstorms, with some possibly strong to severe this weekend.

Currently, an upper level low pressure system was spinning over western Saskatchewan. A surface boundary extends from this system, south southwest through eastern Montana. Scattered showers and thunderstorms were noted behind the surface feature over central and eastern Montana. Isolated to scattered thunderstorms were also located ahead of the boundary, in southeast Saskatchewan and southern Manitoba into northwest and north central ND. The greatest instability this afternoon is situated over northwest ND, however bulk shear here is minimal, but does increase a little north of the border. There is an inverted trough poking into the north central and low lcl heights with increasing low level lapse rates. Although severe weather is not expected a marginal strong gust or hail stone can not be ruled out, along with a non-supercell landspout tornado. Instability here is greatest early to mid afternoon, then diminishes thereafter. late this afternoon and this evening convection from southeast Montana into Wyoming and South Dakota may slide into the southwest portion of the state. ML CAPE here is also forecast to approach 1000 J/kg. Bulk shear here is currently marginal but will increase to around 40-50kts by early this evening. The better potential for severe storms will be west and south of southwest ND, but an isolated strong to severe storm can not be ruled out this evening. The main threats in both areas will be quarter sized hail and 60 mph winds.

Later tonight, the upper low that has been spinning over Saskatchewan the past few days does exit to the east and a vort lobe rounding the base of the upper trough should provide the forcing for ascent to produce scattered to numerous showers and embedded thunderstorms. The position of the impulse would suggest the northern forecast area, especially the north central would favor numerous showers and embedded thunderstorms, with precipitation more scattered in nature over the southern half of the CWA. In the north, the PWAT's are such that if we do see thunderstorms, they could produce some very heavy precipitation rates. WPC has a marginal FF risk mention in this area and the ECMWF SA page notes this area as well for high qpf. Some limiting factors will be the low freezing levels limiting the warm cloud processes you'd like to see. Also MBE movement is slow at times but not consistently slow. However this may be enough for some locally high rainfall amounts tonight. Tall skinny CAPE is conducive to heavy rainfall, but not severe weather. Therefore, heavy rain would be the most likely threat later tonight in the north central, rather than wind or hail.

On Tuesday, the upper low lingers over southern Manitoba, thus the northern half of the forecast area could see some isolated to scattered showers and possibly a thunderstorm. The threat for severe weather on Tuesday looks to be low over western and central ND. It will be a breezy day Tuesday, but at this time the risk for advisory criteria winds is low.

Currently, Wednesday and Thursday look to be the driest days of the forecast period with only hit and miss isolated to scattered showers and possibly a thunderstorm. Upper level ridging will be in control through this portion of the week, while another upper low is taking shape over the Gulf of Alaska and the west coast of British Columbia.

Friday and the upcoming weekend may bring an increase in showers and thunderstorms with a higher potential for strong to severe thunderstorms. Eventually by early next week the western Pacific upper low may end up over the Northern Plains and the southern Prairie Provinces of Canada. But before that occurs we should have a period of unsettled weather with a southwest upper level flow and impulses lifting into the forecast area. The NBM is currently highlighting Saturday and especially Saturday night as a timeframe of widespread precipitation. NBM twenty four hour precip probabilities are pretty impressive with Minot showing a 66 percent probability of an inch or more of precipitation. It's still a long way out so we'll see how this upper low evolves over the work week. Temperatures through the forecast period remain near to a little below seasonable normals. Normal for mid to late June are in the upper 70s for daytime highs and mid 50s for morning lows.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 106 AM CDT Tue Jun 23 2026

Showers and thunderstorms will move slowly eastward across western and central ND tonight. MVFR to IFR ceilings and visibility are possible with localized heavy rainfall with this activity. A band of low clouds is expected along and behind the main precipitation band late tonight and early Tuesday morning, with a high probability of a period of MVFR ceilings and a low to medium chance of IFR ceilings at most terminals. Otherwise, during the day Tuesday, VFR ceilings and northwest winds gusting up to around 25 kt are expected, along with scattered showers and a few thunderstorms in northwest/north central ND.

BIS WATCHES/WARNINGS/ADVISORIES

None.