textproduct: Grand Forks

KEY MESSAGES

- Rain ends from west to east during the day. Localized flooding impacts may be found this morning in a zone from Thief River Falls to just south of Grand Forks to north of Valley City.

..Potential flooding impacts this afternoon & tonight

There remains potential for an additional 3 to 6 inches of rainfall this afternoon through tonight in portions of southeast ND, central/southern Red River Valley, into northwest MN. The majority of CAMs continue to paint this scenario somewhere within the aforementioned areas, but each with their own variety of exactly where this will occur. Locations that experience these amounts are liable to see flooding impacts.

Confidence is relatively high in this output based on the presence of a stationary boundary extending southwest to northeast generally from the southern James River Valley in southeast ND into the central Red River Valley into northwest MN. This sets the stage for additional upper forcing to act upon, which is well advertised to resurge tonight in the form of a shortwave trough propagating out of the High Plains of WY/SD, through the Dakotas, and into northwestern ON by Tuesday morning. This will help reinvigorate the low level jet within the "warm sector" of the aforementioned stationary front - suggested to generally remain in this orientation/position through the event, with some eventual movement eastward Tuesday morning.

Abnormally high moisture content (~1.5 inches of PWATs) coupled with weak but sufficient instability (MUCAPE ~800 J/kg), and storm motion generally parallel to frontal orientation will drive high rain rates. Rain rates like 0.5-1" per hour and/or 2-4" per 6 hours will result in areas that see repeated thunderstorms move over any particular location for at least 2 hours.

Pre-conditioned areas that have recently experienced soaking rainfall is also important to consider when identifying potential areas for subsequent flooding impacts. While these advertised highest rain rates may occur in northwest MN, higher rain amounts from this morning have generally missed this area. Conversely within southeast ND, rainfall from this morning in the 1-2 inch range have already occurred, with continued convective rates from thunderstorms still ongoing in southeast ND at the time of this Forecast Discussion issuance. Despite this area in drought, higher rain rates coupled with previously/currently received rainfall still allow for excessive runoff.

Of course, urban areas are relatively more susceptible to these higher rain rates; this includes cities like Fargo-Moorhead and/or Valley City.

While the overall area of concern holds generally medium to high confidence, more precise location of highest rainfall amounts remain in question. Because of this, have opted to not issue a Flood Watch; however, a Flood Watch may be issued should confidence increase in more precise location of potential area of concern later this afternoon/early evening.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 657 AM CDT Tue Sep 29 2026

Precipitation has moved off to the east and clearing is expected to move across the region from west to east today. VFR ceilings are expected across the region by this evening. Visibility reductions are not expected today. Fog potential will increase in the lakes region (Fergus Falls/Wadena/Park Rapids) of Minnesota Wednesday morning bringing IFR and LIFR (25% chance) conditions. Fog should clear out by 12 PM Wednesday. VFR conditions are expected during the day Wednesday.

FGF WATCHES/WARNINGS/ADVISORIES

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