textproduct: Grand Forks

KEY MESSAGES

- Showers and thunderstorms will bring mainly brief downpours and lightning tonight, although there is still a small chance for some large hail in southeast North Dakota.

- There is low confidence in nebulous chances for strong to severe storms through Tuesday night.

UPDATE

Issued at 1147 PM CDT Sat Aug 8 2026

Showers and thunderstorms starting to develop near the front across our central CWA. So far storms in that area have not been nearly as intense as along the SD/ND border where instability is higher. CAMs are not very impressive with the evolution of the current convection over our area. However, there is still 1000-2000 J/kg of MU CAPE in southeastern ND and with the low level jet ramping up can't rule out some elevated hailers still in our southern counties.

..Synopsis

A primarily zonal jet stream remains fixed across the northern CONUS this weekend into early next week with low amplitude shortwaves riding across the top of a flattened ridge centered across the four corners and extending east into the ArkLaTex. Through the week ridging becomes more pronounced as it shifts east across the southern plains with the jet becoming more anti- cyclonically curved and steering shortwaves more to our north in southern Saskatchewan and Manitoba decreasing chances for rain after Tuesday. Notably we do not look to warm up with this round of ridging so temps will remain in the 70s and low 80s through the next several days for highs.

- Severe risk tonight

Given the increasing density of CAMS and machine learning all highlighting south central and southeast North Dakota this evening there has been a 5% CIG1 introduced for large hail this afternoon. Confidence in coverage still precludes any categorical upgrades however. With most models now honing in on somewhere around 2000 MUCAPE this evening and shear in the neighborhood of 40-50kts, robust rotating elevated supercells seem to be the preferred storm mode if storms form. Weak forcing comes in the form of theta-e advection along a 925-850mb front that will slowly sag south through the night. Sounding analogs support this conceptual model with multiple events of 2.5-3" hail coming up in the SARS system. Even on a low end the expectation tonight (if storms form) would likely be 1.5-2" hail. Given the expected elevated nature of storms the tornado threat looks to be near zero with wind an some uncertainty but perhaps a risk for 60-70mph if a cold pool can establish itself amid the 900-1200 DCAPE. The main threat overall looks to be the hail though from 8pm to as late as 5am with multiple rounds of storms possible.

- Sunday and beyond

With the active zonal jet numerous shortwaves are likely to rotate into the northern plains with machine learning fixating more on the MT/WY/western Dakotas corridor for typical late summer high plains action. However, an at least buoyant airmass comprised of daily SBCAPE values of 500-1000 j/kg and enough shear for some degree of storm organization, and a conditional hail and wind threat is likely to persist each day through Tuesday across the western and southern portions of the forecast area.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 1147 PM CDT Sat Aug 8 2026

VFR conditions continue, with a few showers and weak thunderstorms starting to develop south of KDVL and KGFK. Some shower activity near KTVF also. Have some shower or thunderstorm mention in either VC or prob30 group for KFAR and the MN TAF sites. Confidence not high enough to include any reductions to visibility or ceiling with the thunderstorm activity. Any convection will be away from our TAF sites before 12Z. VFR conditions with winds less than 12 kts mainly in the 340 to 030 range for direction. Winds will become light and variable at most spots by the end of the period.

FGF WATCHES/WARNINGS/ADVISORIES

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