FXUS63 KFGF 121740 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 1240 PM CDT Sun Apr 12 2026 .KEY MESSAGES... - Above average temperatures are forecast this weekend into next week. This will greatly erode existing snowpack. Snowmelt and potential for upcoming precipitation brings a medium chance for minor riverine flooding. - Unsettled weather pattern starts today lasting into next week, bringing chances for precipitation, and perhaps a few thunderstorms. There is also a 30 percent chance for advisory level winter impacts next Friday. && .UPDATE... Issued at 1229 PM CDT Sun Apr 12 2026 Small hail has been observed from the strongest thunderstorms. Hail size has not exceeded more than peas thus far, so impacts should remain limited. This will continue to push east through th early afternoon hours. Ahead of this convection, ongoing dense fog continues in northwest Minnesota, however improvements will continue as the main surface low pushes eastward. As such, the Dense Fog Advisory has once again been extended in northwest Minnesota. UPDATE Issued at 952 AM CDT Sun Apr 12 2026 Dense fog continues across the region this morning. Based on drier air moving in on the backside of the main surface low over southeast North Dakota, the expectation is the expectation that eventually we should see improvements, however current trends indicate this should continue for the remainder of the morning. As such, the Dense Fog Advisory has been expanded and extended through noon. Marginally strong thunderstorms are moving in from the James River Valley and with MUCAPE between 500-1000 J/kg, small hail may arise late this morning in the Sheyenne River Valley. This should remain the main hazard alongside lightning as storms will remain elevated through the morning. UPDATE Issued at 635 AM CDT Sun Apr 12 2026 Areas of dense fog continue to spread east this morning along a warm front. Visibility observations range from 1/4 mile to 1 mile across much of the area. Expanded the dense fog advisory to cover areas of fog through 10am. UPDATE Issued at 1151 PM CDT Sat Apr 11 2026 Worst visibility from obs and web cams still mostly in the Devils Lake basin down our western counties and the Red River Valley near the SD border. Further north across the central and northern Red River Valley as well as into MN, more drizzle/rain as seen on web cams, and vis has been mostly above 2 miles. Will continue to keep the dense fog advisory as it is for now, and will see what happens when the low level lift bringing the drizzle moves off to the northeast later tonight. Further out, not too many changes to what we have going. Still looking like some light showers tomorrow, and some light precipitation Monday night into Tuesday. NBM ensemble has backed off a bit from day shift run on wintry precipitation for Friday. Probabilities for anything over an inch are around 20 percent and warning level snow probs look minimal. However, there is still a cluster of around 17 percent of the ensemble that has a deeper trough and can't completely rule out winter impacts quite yet. Will keep the key message we have going. && .DISCUSSION... Issued at 341 PM CDT Sat Apr 11 2026 ...Synopsis... Upper troughing over the Intermountain West is viewable on water vapor imagery this afternoon, and will deepen into the north- central tier of the CONUS. This is helping draw up higher moisture content from the south, while also increasing synoptic forcing for ascent, especially with one or more shortwave troughs moving into the Northern Plains/Upper Midwest this evening and Sunday. The increase in low level moisture and increased forcing aloft will continue light rain/drizzle tonight into Sunday. The previous signal for thunderstorms into our area Sunday has trended downward, with most forcing for ascent to overcoming likely capping displaced from our area to the south and east. This begins a relatively lengthy period of southwesterly/quasi- zonal flow aloft, promoting a more unsettled weather pattern. Several shortwave troughs will be embedded within this upper regime, although there remain some uncertainty in exactly how each of these shortwave troughs evolve. This includes potential for accumulating snow and potential winter impacts. More details on this can be found below. Ahead of the upper troughing and attendant surface low pressure will be well above average temperatures aloft. This will translate over our area bringing above average temperatures Sunday with high temperatures forecast as high as the 60s and 70s. There will be additional periods of similar temperatures later this week, while staying well above freezing through at least Thursday. The combination of lengthy well above freezing temperatures and upcoming precipitation chances will contribute to chance for minor riverine flooding for a few tributaries in Minnesota. More details on this below. ...Unsettled weather pattern ahead... Ensembles continue to agree in the upper pattern remaining in this southwesterly and quasi-zonal flow regime through at least the end of the work week. While ensembles have some disagreement in synoptic evolution of shortwave troughs, there are a few periods of note that increase our relative chances for precipitation. These periods are tonight into Sunday, Tuesday, and late next work week. For tonight/Sunday, there is a noteworthy amount of warm air in the mid layers effectively capping much available instability for more robust convection. Additionally, strongest low/mid level forcing for ascent to potentially overcome capping will remain displaced to the south and east of our area. Thus, expecting mainly scattered showers with perhaps some embedded thunder forced by vorticity advection from the heart of the shortwave trough itself. There is still expectation of subsequent shortwave troughs to bring their own waves of instability within their warm sectors, but still more likely to be largely displaced from our area. However, convection fed by this warm sector may be within our area, introducing thunderstorms into the forecast. Most ensemble guidance generally agrees that more significant precipitation amounts over 2 inches will remain well to our east within eastern MN into WI. Still, there is a low to medium chance for 1-2 inches within Minnesota and locations north of US Highway 2 by end of the work week. The late week shortwave trough passage may feature cold enough air for some of its precipitation to be snow, of which may be enough to accumulate. As we inch closer to this period, ensemble guidance is starting to cluster toward a scenario that features heavy snow in the eventual system's deformation zone. This could overspread portions of our area, including accumulating snow more than 6 inches. This may also coincide with gusty winds to introduce impacts from blowing snow into this scenario. While there is the potential for warning level impacts from accumulating snow of 6 or more inches and blowing snow, details on placement and timing remain very much unknown. This keeps chance for warning impacts around 10%, with chance for advisory impacts around 30% at this time. ...Warm temperatures and eroding snowpack brings chance for riverine flooding... Due to the extended period of well above freezing temperatures over the next several days, confidence for a greatly eroding snowpack is high. There remains widespread frozen and/or saturated soils, with several areas still seeing standing water in open fields (as seen from webcams and satellite imagery). This lends confidence that existing water content within the snowpack will largely runoff into rivers/tributaries. The current water content within the snowpack isn't overly high (up to 1.2 inches), and alone will likely not push rivers/tributaries into flood stage. However, the combination of this occuring with upcoming chances for additional precipitation introduce a medium chance for minor riverine flooding. Additionally, phasing of snowmelt-driven increased flow within tributaries and main stem Red River may phase with each other in the central Red River Valley. For these reasons, additional river flood watches have been issued. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1229 PM CDT Sun Apr 12 2026 IFR to LIFR cloud decks will continue to linger through the entire TAF period with variable coverage in cloud cover, causing changes in flight categories between VFR to LIFR. Visibility- wise, dense fog should improve through the early afternoon at TVF and BJI, being replaced by showers and thunderstorms. Thunderstorms may be capable of pea to penny size hail. Additional thunderstorms may develop this afternoon in northwest Minnesota, potentially impacting BJI. These have the potential to produce much stronger hail sizes. As we progress into the evening and overnight hours, the low ceilings will continue through the overnight period with aviation impacts generally limited to this. Additional drizzle are possible through the overnight period with some visibility reductions from mist possible, but confidence is too low to add to the current TAF issuance. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...Dense Fog Advisory until 2 PM CDT this afternoon for MNZ001- 002-004>009-013>017-022-023. && $$ UPDATE...Lynch/Perroux/JR DISCUSSION...CJ AVIATION...Perroux