textproduct: Bismarck

KEY MESSAGES

- Another round of isolated to scattered severe thunderstorms is possible this evening through Monday. Main hazards will be hail up to 2 inches in diameter and wind gusts up to 70 mph. An isolated tornado is possible.

- After a subtle cool down to start the week, above average temperatures are favored starting the middle of this week, potentially warming to well above average heading into the Fourth of July holiday weekend.

UPDATE

Issued at 720 PM CDT Sun Jun 28 2026

Pulsey thunderstorms have begun to develop across portions of northwestern and south central North Dakota at the time of this early evening update. While a fairly robust convective environment is found across western and central North Dakota, with mesoanalysis revealing around 2000-3000 J/KG MUCAPE and 0-6KM shear around 45 to 60 knots, the lack of even a moderate forcing across the area has so far kept storms fairly pulsey in nature. The exception to this is far northwestern North Dakota into southern Saskatchewan, where storms have become a little more developed as they move into the left exit region of the a NE-SW oriented upper level jet draped across the northern plains. As we head into the mid to late evening, storms are expected to become elevated as MLCIN increases across the board, but CAMs continue to advertise the potential for strong to severe storms developing by this period. With this update, have tweaks PoPs to account for the latest radar and short term model trends. Have also added patchy fog across portions of central North Dakota, mainly west of Highway 83.

DISCUSSION

Issued at 345 PM CDT Sun Jun 28 2026

Upper low will linger to the northwest tonight. Meanwhile a surface low developing in the across the central plains will continue to provide ample moisture and instability to the area. The result will likely be another round of thunderstorms tonight, especially late tonight. Currently there is high amounts of instability and shear, some of it minimally capped, although capping may return this evening. However, lift is limited at the moment given the two mentioned lows are not quite to the area. A favorable jet location has been enough to develop some elevated showers and thunderstorms this afternoon, and may continue to do sot through at least the early evening. Chances for severe weather with these storms will be limited given the elevated nature of the storms. Later this evening and especially through the night, embedded waves rotating around the upper low combined with a northward shift of the surface low will bring higher chances for showers and thunderstorms. These storms could tap more into the high amounts of instability and shear, although may still remain somewhat elevated. However, the high amounts of shear (with a shear vector angled to perpendicular at times) could support rotating yet elevated supercells. Thus hail up to 2 inches will be the main threat. High 0 to 3 KM shear and adequate DCAPE would support wind gusts to 70 mph. This wind could be in excess of 80 mph as some CAMs have the upper level jet intersecting the MUCAPE axis. This is a lower confidence scenario but one to keep an eye out for late tonight into Monday morning. Given the elevated nature of these storms, the tornado threat is low tonight although an STP greater than 1 and the possibility of supercell interactions will bring at least some low chances for tornadoes. SPC has maintained a Marginal to Slight Risk for severe weather potential, mainly for the storms overnight tonight. Otherwise look for lows in the 50s and 60s tonight. Any clearing combined with light winds could bring some patchy fog tonight, although confidence in this development is low at this time.

Widespread showers and thunderstorms, with isolated to scattered severe storms, could then be found Monday morning and throughout the day Monday. SPC has a Marginal to now Slight Risk for severe weather Monday, with a focus on Monday morning and any redevelopment Monday afternoon. Fairly similar setup for late tonight will the upper low moving more into the area and the surface low moving through. High amounts of shear and cape will be found during this time period. The angle to the shear vector is somewhat uncertain as it will depend on the boundary storms form on. Thus a mix of multi cell and super cells are the likely. The same hazards will be likely with hail up to 2 inches in diameter, winds to 70 mph, and perhaps an increase to the isolated tornado threat. Of concern are the potential for multiple rounds of severe weather Monday, the first being right way in the morning and the second in the afternoon. Thunderstorm chances then start to diminish in the evening as the upper low moves north. Otherwise look for slightly cooler temperatures on Monday except across the southeast where mid to upper 80s are forecast. Some higher dewpoints in the southeast could also bring some moderate heat risk. Chances for showers and thunderstorms retreat to the north Monday night, with low threat for severe weather as instability decreases. Lows in the upper 40s to upper 50s are forecast.

Other than a few stray showers or thunderstorms, Tuesday through Tuesday night then looks mostly dry. NBM forecast today came in with much stronger west winds for Tuesday, indicating advisory level winds possible. ECMWF EFI values have increased somewhat, and are currently highlighting the Highway 2 corridor. Something to monitor going forward. After which, periodic showers and thunderstorms are possible through the weekend as embedded shortwaves within southwesterly to westerly flow aloft push through the region. Though some uncertainty remains, deterministic models are in fair agreement that direct Gulf moisture will frequently be cut off during most, though not necessarily during all time periods. How this evolves will highly impact severe potential during the Holiday weekend, as well as just how high heat indices become.

High temperatures will gradually increase through the week as a ridge builds over the Northern Plains and Midwest, with the current NBM favoring the warmest day overall as July 3rd. This includes the warmest ambient and apparent temperatures. Latest NBM does show a potential slight cooling trend this weekend as an upper low breaks down ridging over the Northern Plains. However, moderate uncertainty remains in regard to the forecast for the holiday weekend.

BIS WATCHES/WARNINGS/ADVISORIES

None.