textproduct: Grand Forks

KEY MESSAGES

- There is a level 2 of 5 risk for severe thunderstorms late this afternoon and evening for parts of southeast North Dakota and northwest Minnesota. Hail to the size of ping pong balls, wind gusts to 60 mph, and a few tornadoes will be threats.

- Heavy rainfall may lead to localized flash flood potential in urban or poor drainage areas through this evening.

..Synopsis

SW flow ahead of a larger mid level trough is in place across the Northern Plains, with a PV height anomaly associated with a mid level shortwave ejecting into eastern ND within this flow. Higher level clouds in SD to the south of this PV anomaly could be the next area of forcing that could trigger initiation along the frontal zone in the 22-00Z period. The frontal zone is currently in place from Lake of the Woods to just south of Grand Forks and just west of Fargo and is starting to show signs of moving east-southeast on radar/satellite ahead of this mid level wave. Good forcing for ascent and at least elevated instability will continue to support showers and thunderstorms (some severe) into the evening before dry/stable air arrives later this evening/overnight.

The larger scale trough/upper low becomes a more dominate feature for our region through the week as it stalls and deepens over the Hudson Bay region and flattens the larger scale ridging to the south. This results in either weaker NW flow or westerly flow and the stronger storm track mainly remaining in Canada. However, flow will at least periodically allow for some influence of waves rounding the mid/upper low and periodic shower/thunderstorm chances. The signal for PoPs is generally washed out by the variability of these features in Canada, and machine learning is not highlighting a specific period for impacts.

After cooler than average temperatures Tuesday, this pattern will generally support temperatures in seasonal ranges for most days into the weekend (+/- 1 standard deviation of normal), and a break from the much hotter temperatures in the 90+ range.

...Severe Thunderstorm Risk Today..

Very high effective shear will be in place with values already in the 50-70kt range across our CWA. As deeper layer shear vectors will tend to be parallel or near parallel to the frontal zone there should be a tendency for clustering of thunderstorm activity that develops later this afternoon/evening. Severe mode and coverage will ultimately come down to timing of initiation and continued destabilization along/ahead of the frontal zone before sunset. Shear profiles support supercell development, however discrete mode may be hard to come by outside of the early part of initiation. Tornado threat will require surface based parcels which for now appear hard to come by, however with clearing that is just starting to occur in southeast ND/west central MN ahead of the front cap erosion could continue and create a window for this threat early in the event with right movers that do develop. More likely scenarios favor elevated cells and at least a window for transient elevated supercell threat which would primarily favor large hail as a threat. Whether clusters can grow upscale with strong enough cold pools in this shear profiles. Line normal vectors are going to tend to be towards the northeast (though the critical angle will be a bit higher due to the strong shear environment).

Backward propagation or training potential along the frontal zone raises the potential for localized heavy rain threat particularly with PWATs exceeding 1.5" along the front. As the front should be progressing quickly eastward there shouldn't be more than 1-3hr of this type of training, but this could be enough with higher rats for localized flash flood potential if this happens over a town/urban area where there is poor drainage.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1247 PM CDT Mon Aug 3 2026

Highly variable flight conditions (visibility and wind) are ongoing across eastern ND and northwest MN as a result of shower and thunderstorm activity and a stalled frontal zone early in the TAF period. There is also some surface level smoke arriving behind the front, but so far visibility impacts have been tied to where shower/thunderstorm activity is tracking. Eventually the front will push east and southeast and additional shower and thunderstorm development (including potential severe thunderstorms) will occur with coverage filling in across northwest MN late afternoon and evening before transitioning east and southeast of the region.

As the front passes there is a signal for MVFR ceilings as well in northwest MN which may linger in north central MN into the morning hours Tuesday. Winds should shift to the north then west-northwest behind the front this evening, but before then will be highly variable in direction and speed.

FGF WATCHES/WARNINGS/ADVISORIES

ND...None. MN...None.