textproduct: Bismarck

KEY MESSAGES

- Scattered severe thunderstorms are likely Thursday afternoon and evening. The main expected hazards include hail up to 2 inches in diameter and damaging winds up to 80 mph, with a tornado possible.

- Medium to high chances for showers and thunderstorms Friday through Friday night, with a low risk for isolated severe thunderstorms. Low to medium shower and thunderstorm chances remain in the forecast through the holiday weekend.

- Near to above normal temperatures favored through the holiday weekend, with widespread highs in the 90s possible after Independence Day.

UPDATE

Issued at 1241 AM CDT Thu Jul 2 2026

Line of thunderstorms over eastern Montana continues to progress easterly. There have been some marginally severe wind reports with this line, but they have been few and far between lately. With that said, the line has extended further south than any guidance has indicated, so for late night update have adjusted precipitation chances accordingly.

UPDATE Issued at 1108 PM CDT Wed Jul 1 2026

A lone thunderstorm was able to sustain for a couple hours earlier this evening between Medora and Amidon, but has since dissipated. Recent model guidance has increased probabilities that convection moving into northeast Montana late this evening will make it into northwest North Dakota later tonight, and continue to migrate eastward into Thursday morning. Low to medium chances for showers and thunderstorms have been introduced to the forecast to account for this potential. Severe weather is not anticipated with this activity through Thursday morning.

UPDATE Issued at 733 PM CDT Wed Jul 1 2026

No significant forecast changes are needed for this update. A few isolated showers have developed in far southwest North Dakota. These could continue to percolate until around sunset. Smoky skies are expected to prevail through at least tomorrow. Despite below average air quality, with visibility restrictions remaining above 5 miles will not add a mention of smoke to the forecast at this time.

DISCUSSION

Issued at 1239 PM CDT Wed Jul 1 2026

Latest satellite and radar imagery shows convection has ended over the far south. Isolated to scattered showers continue along the International Border, mostly in Canada, but some shower activity is sneaking down into northern portions of Bottineau and Rolette Counties this afternoon, and perhaps northern Renville. Most of western and central ND was under mostly sunny skies with westerly winds of 10 to 15 mph and temperatures in the 70s to lower 80s. All in all an nice day for all the activity going on today.

We are carrying some slight chance pops in the southwest and south central this afternoon and early evening. Some of the latest CAMS do show shower activity developing in the southwest this afternoon and a cu field has developed over the southwest in the past hour or so. Will keep the pops for consistency but the instability is weak and shear is nil so the severe threat is very low. There may be a weak impulse within the southwest upper flow moving into ND, but overall, upper level ridging will be over the area this afternoon/evening.

Quiet overnight, with lows mainly in the 50s.

We ratchet up the threat for severe weather tomorrow. A broad southwest upper flow remains over the area with increasing low level moisture with dew point temperatures climbing into the 60s. A very unstable airmass develops by Thursday afternoon with a Cap being eroded with daytime heating and warm advection. There is a surface trough over western ND by mid afternoon with shortwave energy approaching from Montana. At this time, it looks like convection could develop over western ND near the surface trough, and along an east-west boundary, although there is a lot of uncertainty as to where the boundary is Thursday afternoon and if/when convection develops along it. Cams are showing differing solutions along the E-W boundary from convection along the ND/SD border, to along the I-94 corridor. Convective initiation varies from early afternoon to late afternoon so a lot of uncertainty remains in the timing/placement of convection Thursday. If/when convection does develop there is maybe a little more certainty in the mode. Convection along an east-west boundary looks to be mixed/messy with an inclination to grow upscale into a MCS with winds to 80 mph the main threat. An initial supercell can not be ruled out though before linear convection prevails. The better potential for initial and longer sustained supercells (with large to very large hail to around 2 inches) would be over western ND near the surface trough. With larger T/Td spreads here (especially the west central to southwest) the tornado threat would be lower, but not zero, given the strong instability and storm mode. Finally with precipitable water increasing to greater than 1.5", any thunderstorms will have the potential to produce very high precipitation rates, with localized areas of excessive rainfall. Hopefully as we get closer to Thursday afternoon, things will become clearer. An enhanced risk is not out of the question if some of these uncertainties become better calibrated Thursday afternoon/evening. But for now the higher wind potential looks to be in the south central/southeast, or wherever the E-W boundary ends up. The threat for to very large hail would be associated with longer sustained supercells, which would point to western ND, with also a transition to a more linear wind threat over time. The threat for a tornado can not be ruled out in either area, but is lower than the hail/wind threat. The same can be said for the threat for very heavy rain.

Friday will bring another round of strong to possibly severe storms. At this time it looks like there may be some upper level ridging and a transition from more of a southwest flow to a zonal flow. This may lower the overall severe potential, but we will see how this plays out. For now we will go with quarter size hail and 60 mph winds for the main hazards.

Over the Holiday Weekend, thunderstorm chances will continue but at this time it looks to be low to medium chances for thunderstorms, rather than medium to high chances. Diurnally driven afternoon/evening instability will exist each day, but with marginal bulk shear, at least for now. We will have to play it on a day to day basis for any eventual severe threat over the weekend. Sunday and into early next week the heat does ratchet up with some areas seeing mid and possibly even upper 90s for daytime highs.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1241 AM CDT Thu Jul 2 2026

Thunderstorms are expected to push into western North Dakota from Montana around 07-08Z, then continue sliding to the east. There is some question as to whether these storms will dissipate, or continue pushing east through the early morning hours. Smoke aloft could remain thicker throughout the forecast period, but is not expected to reduce surface visibility below VFR levels at this time. Clusters of showers and thunderstorms are forecast to develop Thursday afternoon and continue into the evening. Some storms may be severe with large hail and +50 kt wind gusts. Any storm will be capable of heavy downpours briefly reducing visibility to at least IFR levels.

BIS WATCHES/WARNINGS/ADVISORIES

None.