textproduct: Bismarck

KEY MESSAGES

- Marginal (level 1 out of 5) to Slight Risk (level 2 out of 5) of severe weather on Tuesday.

- Low to medium chances of showers and thunderstorms Wednesday through the remainder of the week.

UPDATE

Issued at 1242 AM CDT Mon Jun 1 2026

Scattered showers and thunderstorms remain generally along and ahead of frontal boundary that now stretches from near Stanley south-southeastward towards Bismarck where instability corridor of around 500 J/Kg is noted. Have had a few storms pulse up a little but fall off rather quickly, and expect this trend to continue as the boundary continues its eastward progression. Have adjusted precipitation chances accordingly.

UPDATE Issued at 956 PM CDT Sun May 31 2026

Modified POPs a bit based on latest radar and trends for this late evening update. Instability axis and front continues to slowly move east, with showers and thunderstorms over across southwest and west central ND. The threat for stronger storms has been on the decrease the past few hours with the loss of daytime heating.

UPDATE Issued at 655 PM CDT Sun May 31 2026

Showers and thunderstorms continue along an occluded front arcing from south central North Dakota back northwest into northwestern ND. Modified POPs to better capture latest radar and trends/CAM output. Best instability and environment for stronger storms (albeit pulse/short lived stronger updrafts) resides from across portions of eastern South Dakota into parts of south central North Dakota. A few robust storms across Emmons County, though sub-severe and not expecting anything more this evening. NST parameter increasing along the front, so something we will watch going forward this evening. Push of westerly winds in the wake of the occluded front as it pushes east tonight will see convection ending west to east now through early Monday morning.

DISCUSSION

Issued at 350 PM CDT Sun May 31 2026

Surface low will retreat into southern Canada tonight, pushing a cold front across the state from west to east this evening through tonight. Isolated to scattered thunderstorms are expected as this front moves through. SPC has maintained a Marginal Risk for severe weather in south central North Dakota. This area has modest CAPE 1000 to 2000 J/Kg with ample heating and increased dewpoints in the 60s today. Shear is lacking today, with effective shear 25 to 30 knots. Shear vector is angled to the front indicating multicluster storms the likely storm mode today. Mid level lapse rates also look lacking today, although steep lapse rates are found in the lower levels. Given modest CAPE and some shear, pulse multi cell storms could bring winds gusts up to 60 MPH winds and hail up to quarter size through this evening. With steep low level lapse rates and increased CAPE in these lower levels, perhaps a non-supercell funnel cloud is possible through this evening. The lack of low level shear should limit this threat. Otherwise look for a breezy southeast wind to become a breezy westerly wind during front passage. Precipitation will push eastward through the night. Cooler temperatures will move in behind this front tonight with lows in the 40s west to lower 50s east. A cooler post frontal day is then expected for Monday. Look for breezy westerly winds through the day, especially in the northwest. Precipitation chances should be minimal with perhaps some light chances in the north along the stalled front. Look for highs in the 60s northwest to near 80 southeast. Upper upper low stalled in Canada approaches western ND Monday night. This could return chances for showers and thunderstorms in the west. Lows will remain cool in the 40s to lower 50s.

Upper low remains in the area for Tuesday and Wednesday. Warming temperatures and increase moisture from a southerly flow will bring modest instability to the area. Shear will also be increased from the upper level low aloft. The result could be one to two days of severe weather across the state. Tuesday currently has a Marginal to Slight Risk across much of the state. Strong wind and large hail are the likely main threats for Tuesday. A shear vector angled to parallel to the frontal boundary could limit the discrete supercell potential and the stronger hazards associated with that. Although that could change given this setup is still a few days out. The increased amounts of instability with this system could also provide for a prolonged severe weather threat, with some CAMS starting convection late morning and continuing through the evening. Increased Pwats over an inch are also forecast for Tuesday. With near saturated soils this could lead to some localized flooding especially in central and eastern portions. WPC currently has a marginal risk for excessive rain. Similar conditions may be found on Wednesday although severe weather and heavy rain threat may shift eastward with the upper low shifting eastward. Lows through mid week will remain in the upper 40s to upper 50s, while high in the 70s to lower 80s can be expected.

Zonal flow aloft could continue the summer like pattern for late in the week as temperatures remain above normal. This combined with weak disturbances in the westerly flow could bring daily chances for showers and thunderstorms. CSU-MLP showing limited threat for severe weather, with perhaps some isolated activity possible during the upcoming weekend.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1242 AM CDT Mon Jun 1 2026

Isolated to scattered showers and thunderstorms will continue overnight over central North Dakota and the James River Valley, possibly lingering into the early morning over north central North Dakota. In addition, areas of MVFR ceilings with localized IFR will be possible overnight over much of western and central North Dakota, possibly lingering into the morning over northwest North Dakota and over the Turtle Mountain region southward into the James River Valley. Thereafter, VFR conditions will prevail.

BIS WATCHES/WARNINGS/ADVISORIES

None.