textproduct: Bismarck

KEY MESSAGES

- Periodic low to medium shower and thunderstorm chances will continue through Tuesday.

- The overall threat for severe weather is low through the middle of next week, although an isolated strong to severe storm is possible Monday and Tuesday.

- Temperatures will remain below average through the middle of this week, with a slight warm up favored for the end of the week.

UPDATE

Issued at 1254 AM CDT Mon Jun 22 2026

Limited changes needed at this time. An unorganized area of showers will continue to push across western and central ND through tonight. Some light rain is possible at times. Behind these showers, some low level moisture is moving into the area, especially across the southwest. This could lead to some low clouds and perhaps patchy fog tonight into Monday morning. Made some minor PoP adjustments based on the latest radar trends, while also adding in some patchy fog mention in the southwest. Otherwise the forecast remains on track.

UPDATE Issued at 954 PM CDT Sun Jun 21 2026

The area of showers is becoming less-organized as it approaches the Highway 83 corridor, as expected. The 00z Bismarck RAOB had a sufficiently-moist profile to support a low chance of showers that far east, but CAMs and radar trends suggest the coverage will continue to diminish concurrent with ascent aloft, especially in south central ND. CAMs suggest regeneration of showers is possible in northwest and north central ND overnight in closer proximity to the weakening impulse aloft. The overall picture is well-handled by the previous forecast, so only minor changes were made with this update cycle.

UPDATE Issued at 652 PM CDT Sun Jun 21 2026

An area of showers stretching from near Bowbells to Stanley, Killdeer, and Dickinson continues to slowly move eastward as of early evening. The weak impulse aloft helping to drive this area of precipitation is expected to dampen with eastward extent and time, and PWATs also drop below an inch east of the Highway 83 corridor. As a result, the CAM suggestion that these showers will diminish by 06z and with south and eastward extent appears to be on track. However, we needed to boost PoPs based on radar trends this evening near and immediately downstream of the area of precipitation, and lingered them overnight in northwest and north central ND in closer proximity to residual, albeit weak forcing for ascent aloft. Midlevel lapse rates are relatively weak, and low-level moisture is seasonably modest, which has resulted in meager bouyancy. As a result, lightning production has and is expected to be minimal, and focused with the weak upstream convection in northeast MT that may move into northwestern ND this evening.

DISCUSSION

Issued at 219 PM CDT Sun Jun 21 2026

Upper Canadian low over southern Alberta continues to churn ever so slowly eastward. Along with associated surface low over central Montana, this is producing a line of showers in eastern Montana that have been gradually working into western North Dakota. Currently, there isn't a lot of instability available. However, with a marginal increase in low-level lapse rates and instability progged later this afternoon, a few thunderstorms may develop. That said, shear looks marginal as well with only 20 to 30 kts of 0 to 6 km bulk shear forecast. As such, the probability of severe weather today is low. Showers and a few thunderstorms are favored to persist and expand eastward overnight tonight mainly north of I94.

Aforementioned upper low should see somewhat of an increase in speed as it propagates eastward through Tuesday, while simultaneously winding up to some degree. This will result in another round of showers and thunderstorms starting in western North Dakota Monday afternoon and gradually passing from west to east across the state through Monday night. With a little bit stronger shear and possibly more instability to work with, could see a few strong thunderstorms Monday afternoon and early evening mainly in western North Dakota. A brief severe thunderstorm or two isn't entirely out of the question either. The most likely threat would be quarter size hail. As the upper low slows back down Tuesday before beginning a gradual descent towards the Great Lakes Region, another round of showers and thunderstorms is then likely for much of northern and eastern North Dakota on Tuesday. Tuesday looks to be another day with limited instability, though strong shear could lead to an isolated strong storm or two.

Mostly dry conditions are then favored for Wednesday and Thursday, though cyclonic flow could produce scattered showers Wednesday afternoon, especially in northern and eastern North Dakota. Models maintain some divergence after that. However, the potential exists for an upper low to dig into the northwestern CONUS possibly bringing southwesterly flow aloft back to the region. This could bring the return of severe weather chances towards the tail end of this week. For being a week out, the NBM is also pegging unusually high PoPs Saturday through Sunday.

Temperatures are favored to remain below average (5 to 10 degrees) to the low side of average (within 5 degrees) for most locations, most days through Friday. This forecast is a bit cooler towards the end of the week than prior days, though some low 80 degree readings remain in the forecast mainly for next weekend. Of note, confidence in the temperature forecast is fairly high through Thursday, then much lower beyond that.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1254 AM CDT Mon Jun 22 2026

Showers will move across the forecast area tonight, although confidence was only high enough to include PROB30 groups at KMOT. Some lower clouds may move into the southwest bringing some MVFR ceilings and perhaps patchy fog. These MVFR ceilings could impact the KDIK area, with confidence too low to include fog mention in any TAFs. Mainly VFR conditions are expected through the day on Monday. Another round of showers and thunderstorms may move through from west to east later Monday through Monday night. Most sites have PROB30 groups to account for this potential. This shower activity could bring some MVFR conditions at times.

BIS WATCHES/WARNINGS/ADVISORIES

None.