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 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 /06Z TAFS THROUGH 06Z MONDAY/

Issued at 1144 PM CDT Sat May 16 2026

VFR conditions should prevail through 12Z Sunday across eastern ND and northwest MN. Northeast winds gradually shift to the east and increase through the early TAF period. As low pressure builds to the south of the region winds should increase above 12kt, with gusts around 25kt through the day Sunday. This system will bring periods of rain showers starting in the west and working east after 15Z through the afternoon. Rain showers should end in ND during the early evening hours, and are more likley to linger through Sunday evening over northwest MN. The best chance for embedded thunderstorm (30%) is at KFAR during the late afternoon period (lower chances elsewhere).

The increase in low level moisture will also bring MVFR ceilings to the region as rain arrives, with IFR ceilings eventually developing and prevailing across the region by the evening hours. Due to the amount of low level moisture there is a chance that LIFR ceilings develop (300-400ft agl) late Sunday evening along with light fog (3-6sm) after the rain ends, with better chances in central ND.

FGF WATCHES/WARNINGS/ADVISORIES

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