textproduct: Grand Forks

KEY MESSAGES

- Minor chance for isolated flash flooding tonight across southeast North Dakota and west central Minnesota.

- There is a level 1 out of 5 risk for isolated to scattered severe storms tonight through Sunday.

..Synopsis

Relatively low amplitude longwave ridging will allow a series of shortwaves to permeate east along the top of the ridge through early next week bringing above average moisture to the region for the 6-10 day period. With these shortwaves will come a minor risk of flash flooding and low end severe chances (mainly wind/hail) each day through Sunday. Beyond these threats the rains will certainly be welcome and beneficial to easing the worsening drought though is likely too little, too late for many crops unfortunately and may even put a short stop to the ongoing wheat/sugar beet harvest. Dry/hot Ridging does briefly return for the middle of next week before we transition to prevailing SW flow aloft indicating another wet period though uncertainty remains on any amounts or associated hazards (flooding/severe).

- Today

Machine learning remains pessimistic overall about the chances for any severe weather tonight with hail being the only thing really sticking out. Overall buoyancy is pushing 2000-2500 MUCAPE with 40kts of eff shear. Overall the marginal risk for a couple quarter sized stones is warranted but the threat seems to be more of a heavy rain one. The saturated profiles aloft could be an artifact of convective contamination on the CAMS but assuming they are not that type of profile does not fit the conceptual model for efficient hail growth. Conversely the elevated nature of parcels given inflow layers around 800-850mb and long straight hodos should favor hail growth. Its really a tossup between if hail occurs or it goes the way of efficient warm cloud layers producing a predominant heavy rain threat. Should hail occur analogs support hail of golf ball to baseball but would think the max size would trend toward the lower bound of that range.

That said the pattern does overall resemble the Maddox Frontal Pattern with the ridge to the western and a shortwave paralleling the stalled 850-700mb front. Sustained overnight southerly moisture return along with general WAA across the front combined with cloud layer (850-300mb) shear of ~40kts atop deep moisture convergence should favor repeated training storms in southeast North Dakota and west central Minnesota overnight. Some CAMS are outputting areas of 2-4" with many areas likely to see at least quarter inch tonight easy the drought south of HWY 200. The confidence in these higher totals manifesting is currently too low to issue a Flood Watch but it remains something to be monitored tonight (10pm to 8am).

- Saturday

Another shortwave is forecast to crest the flattening ridge on Saturday with a developing surface low on the MT/ND border. This will bring more strong southerly moisture return to north central North Dakota and a marginal risk for severe weather to the western 2/3rds of the state. A few strong storms may make into the Sheyenne river valley but most stay west of the Red River Valley. HREF PMM is showing areas of 1-2" with this activity but it mostly remains west of our forecast area unfortunately. Could still see a few areas in north central North Dakota with amounts exceeding a quarter to half inch but those will be the lucky few rather than the norm for our forecast area.

- Sunday

More storms are yet again expected Sunday afternoon/evening as yet another shortwave moves east through Montana initiating storms along the state border around 5-7pm working east as an line as eff shear of 40-50kts and MUCAPE of 2500-3000 looks to favor linear modes with time. Right now the ceiling looks to be a strong MCS perhaps with hail initially west of Bismarck and winds up to 70mph out here. Should the low levels be favorable some mesovortex type tornados cant be ruled but will have to monitor that threat more over the next 24 hours as CAMS become available.

- Next Week

Near zonal to southwesterly flow aloft continues into next week. Temps look to be above average with several chances for precipitation as weak shortwaves come through. Timing and intensity of any storms still uncertain with such weak forcing and unknown instability.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1218 PM CDT Fri Aug 28 2026

VFR conditions are expected through much of the period except tomorrow morning out east in BJI where moist flow on the north side of a passing low should saturate the low levels and lead to MVFR CIGS for a couple hours. Winds remaining south to southeast overall and light at 5-10kts for most but some 12-15kt pockets remain through the afternoon today. An incoming shortwave will increase cloud cover through the evening with widespread overcast conditions by 00z which will remain through tomorrow afternoon. Thunderstorms do appear likely through the central and southern valley overnight but choose to prevail showers for now and VCTS where applicable due to low confidence in the location of thunder.

FGF WATCHES/WARNINGS/ADVISORIES

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