


Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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219 FXUS63 KFGF 131459 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 959 AM CDT Sun Jul 13 2025 .KEY MESSAGES... - Another round of wildfire smoke will degrade air quality later this afternoon into evening in northeast North Dakota into northwest and west-central Minnesota. - There is a level 1 out of 5 risk for severe storms both late Monday and Tuesday. The main hazards will be gusty winds, hail, and flash flooding. && .UPDATE... Issued at 959 AM CDT Sun Jul 13 2025 Pretty quiet this morning with a bit of a break between rounds of smoke currently. However, next push of smoke is seen on satellite about to cross the international border, and will continue to push south and east the rest of the day. UPDATE Issued at 731 AM CDT Sun Jul 13 2025 Morning sunlight reveals next batch of wildfire smoke is currently making its way through southern MB. On its current trajectory, it will start to infiltrate areas north of US Highway 2 late this morning, with areas south in the afternoon. There is still a chance that smoke will bypass some locations near central and southeast ND, with thickest smoke likely to be more within northwest Minnesota late morning into early afternoon. It remains unclear how thick smoke is at the surface due to sparse observation dataset where smoke currently resides as well as upstream of its location. Thus will continue to message potential impacts to all populations as talked about in the Discussion below. && .DISCUSSION... Issued at 357 AM CDT Sun Jul 13 2025 ...Synopsis... Departing shortwave upper trough/low is exiting the western Great Lakes region into ON as seen on water vapor imagery early this morning. In its wake, northwest flow aloft will persist continuing to advect continental air mass originating from Canada today, with an additional cold front set to move through the area today. This will bring another, final round of wildfire smoke behind the cold front into the region degrading air quality. More on details on this can be found below. Flow aloft then turns more zonal over the Northern Plains and Upper Midwest as large upper low over the Hudson Bay begins to develop early next week. This will promote entrance region upper jet dynamics to overspread the Northern Plains, promoting lee troughing/frontal development at the surface, increasing overall forcing for ascent within the region. This also will promote moisture return from the south into the Northern Plains and Upper Midwest along with increasing instability. With forcing for ascent increasing over the region, chance for showers and thunderstorms increases Monday and Tuesday. Widespread medium to high chance for rainfall increases beginning late Monday, lingering through Tuesday. Increased instability and flow aloft will introduce the potential for strong to severe storms during this timeframe over the Dakotas into Minnesota. Additionally, above average moisture content pushing into the region of ascent within the Dakotas and Minnesota along with potential for training thunderstorms will introduce potential for excessive rainfall leading to flash flooding. More details on this found below. As the Hudson Bay low develops further into Thursday and Friday, there will be a tendency for cooler, continental air mass to intrude over the region. Ensemble guidance like ENS EFI continues to note on high probabilities for below average temperatures between Wednesday and Friday. Overnight/early morning low temperatures continue to be forecast into the mid 40s and low 50s. Should ideal radiational cooling conditions occur, there is a low chance for low temperatures into the upper 30s, perhaps more in the typical cooler spots of northeast ND and northwest MN. Drier conditions will also accompany this set up, as well as additional chance for more wildfire smoke to infiltrate the region. ... Wildfire Smoke Today ... Before sunset Saturday, visible satellite imagery showed an area of dense smoke emerge from wildfires within SK behind a passing cold front. This cold front and attendant air mass will move through the area. Smoke guidance continues to show this smoke to move through portions of northeast ND into northwest and west- central MN this afternoon into evening. Observing the thick smoke lends credence to this scenario unfolding, however, there is uncertainty how dense smoke will be behind as it envelopes these areas given the lack of upstream surface observations. Will continue to message increased risk of adverse health effects to all populations today from wildfire smoke today into this evening. ... Severe Potential Late Monday into Tuesday ... There continues to be increased confidence in potential for at least isolated severe thunderstorms within portions of eastern ND into northwest and west-central MN starting late Monday, lasting through the day Tuesday. This is supported by AI guidance like NCAR`s Pangu and FengWu Convective Hazard Forecasts both highlighting increased probabilities above 15% in these areas Monday and now Tuesday. There is still however large uncertainty in how storm evolution will unfold. While confidence is high that window for severe potential starts late Monday (possibly after sunset), confidence in locations and timing through Tuesday is low. This is partly due to the fact that there will be broad scale ascent over the Northern Plains and Upper Midwest with potentially several mid level shortwave impulses moving over a frontal boundary that will gradually push southward late Monday through Tuesday. Additionally, important mesoscale details continue to remain in question that would dictate more precise timing and location. Sufficient instability (potentially moderate instability around the order of 2000 J/kg) and increasing shear (particularly in the lower levels) will drive severe hazards. While low level shear will be high at times, warm low level temperatures and relatively dry lowest levels will preclude tornado potential. High low level shear will however drive potential for wind gusts to 70 mph (with a low chance for potentially up to 80 mph should conditions align right), even for overnight storms Monday night. Additionally, elevated instability aloft and sufficient shear aloft will drive hail potential. Confidence is low on hail size potential, however, hail up to the size of ping pong balls seems reasonable given elevated convection pushing cloud bearing layer closer to freezing temperatures. Additionally, heavy rainfall leading to flash flooding is possible as well. Latest modeled guidance continues to present large swaths of 1-2 inches of rainfall over the Dakotas into Minnesota late Monday and Tuesday, with low neighborhood probabilities of 3-5 inches continuing to show up. Coverage of showers and thunderstorms may be widespread given the generally large scale nature of forcing for ascent with potential for several impulses to move through in this type of synoptic pattern, but will hinge upon other mesoscale factors like instability, boundary orientation/location, and cloud-bearing flow. This lowers confidence in coverage, location, and amount of rainfall. In coordination with the Weather Prediction Center, there has been an upgrade to a small area of level 2 out of 4 risk for excessive rainfall leading to flash flooding over our region for Tuesday. && .AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 731 AM CDT Sun Jul 13 2025 Main impact to aviation today will be another round of wildfire smoke moving into portions of eastern ND into northwest and west-central MN. Smoke will work its way southward starting late morning near the international border, then afternoon into early evening as it continues toward central MN. Sites like KGFK, KTVF, and KBJI hold greatest chance of seeing MVFR conditions from visibility reductions. Otherwise, winds will be out of the northwest around 10-20kt. Very dry air will likely limit amount of daytime cumulus development today. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...CJ/JR DISCUSSION...CJ AVIATION...CJ