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.

..SEVERE POTENTIAL TODAY

Surface analysis this afternoon shows the warm front roughly situated just north of Sioux Falls. This has allowed intense isentropic ascent over our area, bringing some solid moisture content to the region. This warm front remains expected to propagate northward this afternoon and bringing surface moisture with it. CAM guidance continues to generally prog the surface instability south of our CWA, barely scraping Grant County. Per HREF probabilities, there is only a 10% chance to even see 500 J/kg of SCAPE. MUCAPE also is very closely attached to this warm front and shares similar probabilities as a result. Having said that, shear associated with the front is rather strong, approaching 50+ knots. There will be a brief window this evening (likely at most 1-2 hours) wherein severe convection may impact our west-central Minnesota counties. Any severe convection will most likely be hail as storms are likely to be elevated as storm relative winds in the 0-2km layer are most likely to be due easterly, so it will be difficult to ingest warmer air to the south. If surface-based convection arises, tornadoes can't be ruled out but again this is very unlikely at this time and would require very strong propagation northward in the warm front. The window of severe thunderstorms ends roughly close to midnight at the lastest, but should generally be out of the area by 8-10 PM CDT.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1220 PM CDT Sun May 17 2026

Ceilings will lower through the afternoon as showers overspread much of the region. At least MVFR ceilings are expected to develop this afternoon with eventual IFR expected around sunset. Showers will likely reduce visibility in some capacity, but should generally remain in the 3-8 mile range. Later this afternoon, embedded thunderstorms may impact FAR, but the probability is diminishing as we approach since instability remains well south of the terminal. Showers will diminish generally after 00z, but IFR ceilings will remain through the end of the TAF period, with the low potential for LIFR. Winds today will generally be easterly, shifting to northerly towards midnight and prevailing northerly the rest of the way through the end of the TAF period.

FGF WATCHES/WARNINGS/ADVISORIES

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