textproduct: Grand Forks

KEY MESSAGES

- There is a 2 out of 5 risk for a few thunderstorms bringing a threat for 1.5 inch hail Sunday afternoon.

UPDATE

Issued at 650 AM CDT Sun May 17 2026

Showers are just starting to work into central North Dakota this morning, and generally remain on track to enter the CWA heading into Midday. The best probability for severe thunderstorms remains largely to our southeast today; however, isolated to scattered severe thunderstorms could move into the far southern Red River Valley later this afternoon and evening. Model soundings reflect support for large hail up to the size of ping pong balls.

UPDATE Issued at 909 PM CDT Sat May 16 2026

Update to remove key message for the expiration of Red Flag Warning at 9pm. RH values are 40% or higher and winds generally 5-15mph. A Frost Advisory remains in effect for far northwest/north central MN where mostly clear skies/light winds should support good radiational cooling and 2m temps are likely to fall to 36F or lower.

..SEVERE STORMS SUNDAY

As the shortwave ejects tomorrow afternoon, a deepening surface low is forecast to develop in the Central/Northern Great Plains. Accompanying this will be a developing warm front that will push moisture northward towards our area. South of this front, theta-e values exceeding 330 K will provide for a risk of surface-based thunderstorms, while north of the warm front will create a risk for elevated thunderstorms. This will largely drive the hazards that we will see tomorrow afternoon/evening.

As time has gone on, it is appearing more and more likely that we will be on the northern end of the warm front, where very strong isentropic ascent will exist, but with cooler surface temperatures in the 60s. This means we will more likely fall towards elevated supercells capable of hail up to 1.5". On the flip side, this means our tornado risk is also significantly diminished. While ESRH along the warm front is very good with excellent streamwise vorticity, the overwhelming bulk of guidance keeps this south of area. There remains the low chance for this warm front to propagate northward and slice into Otter Tail/Grant/Hubbard Counties, but this looks to be the outlier and absolute northern max within the range of scenarios. The timeframe for severe storms is generally between 3 PM and 11 PM with the most likely zone for severe in the 4 PM to 9 PM timeframe. For any tornado risk, should it arise, this would be closer to the late afternoon early evening timeframe.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 650 AM CDT Sun May 17 2026

VFR ceilings prevail this morning, with MVFR to IFR ceilings developing across most of the area by midday. Look for showers to lift from southwest to northeast this afternoon, with a 30 percent chance for scattered thunderstorms at KFAR and lower chances elsewhere. Reduced visibility is likely during periods of heavier rainfall, especially during scattered thunderstorms. IFR ceilings are expected to continue into the late evening.

FGF WATCHES/WARNINGS/ADVISORIES

ND...None. MN...Frost Advisory until 8 AM CDT this morning for MNZ004>006-008- 009-017.