177 FXUS63 KFGF 251526 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 926 AM CST Sat Nov 25 2023 .UPDATE... Issued at 925 AM CST Sat Nov 25 2023 Flurries are being reported in the southern half of the area, so flurries have been added to the forecast. This will continue off and on throughout the day today, but impacts should remain fairly limited. UPDATE Issued at 703 AM CST Sat Nov 25 2023 An area of mid clouds and associated flurries is moving across southeast ND along the northern fringes of the mid level low near south central SD. This is well removed from the main area of forcing and is undercut by drier air, so other than the novelty of a few flakes, measurable accumulations are unlikely as supported by near term guidance and observed trends. Another area of light returns/mid level clouds is moving out of southwest Manitoba towards north central ND, but so far there haven't been any reports of precipitation reaching the ground with this yet. This is along a weak mid level trough axis that is still farther ahead of the main shortwave expected later tonight. A few flurries can't be ruled out in the Devils Lake Basin this morning as this tracks south, but like the activity in the south impacts aren't anticipated. && .SHORT TERM...(Today through Sunday) Issued at 350 AM CST Sat Nov 25 2023 Key Message: -A fast moving clipper type system and strong cold front brings the potential for minor travel impacts late tonight into Sunday morning. -Primary impacts will be related to brief visibility reductions while snow is falling and strong winds increase early Sunday morning. There is a 20% chance for brief reductions to 1/2 mile or less during falling snow (1-3hr period). Discussion: The large scale pattern continues to feature broad troughing but effectively a slit-flow type regime, with the stronger storm track well south of our region, and the a weaker northern jet featuring drier progressive waves over the next week. Tonight-Sunday: A progressive positively tilted shortwave and an associated cold front will arrive later tonight and with that a broad area of very light snow (high coverage/low amounts) will spread over our CWA with 1-4hr of accumulation as highlighted by HREF. The lack of mesoscale forcing, instability, and progressive nature of the system while deeper moisture advection is cut off to the south limits the upper end of potential amounts during the main period of snowfall. Majority of ensemble members show a few tenths to around 0.5" of snowfall across our area as this passes, with higher totals around 1" (20% chance or less). We are already seeing some ice formation on larger lakes lowering confidence in water temperatures and delta-T being high enough to support lake enhancement of snow and CAMs aren't showing an enhanced signal outside of the ranges we are already forecasting (dusting-1"). There is a post frontal signal for showery activity with steeper lapse rates in place behind the front, but this coverage in the CAMs is very isolated/brief in nature limiting additional amounts. Of more significance is increasing northwest to north winds associated with 6hr pressure rises around 4MB and 925MB winds 30- 35kt. The upper portion of the mixed layers on sounding do approach 40kt (advisory type gusts potential) but in this pattern that would be very brief/localized. Instead the greater impact would be decreasing visibility if these winds align with falling snow. There won't be enough new snowfall to create blowing snow impacts without falling snow. The Canadian blowing snow model shows potential (40%) for 1/2 mile or less visibility based on forecast winds/temperature with falling light snow (a conditional probability). This would align with potential advisory type impacts, but the signal for widespread snow is primarily ahead of the front, and the overlap between the two is more uncertain. There may still be isolated post frontal snow showers for a brief period, but the coverage is much lower after the frontal passage lowering probability of impacts (20%). .LONG TERM...(Sunday night through Friday) Issued at 350 AM CST Sat Nov 25 2023 -Seasonal to above average temperatures are expected through next week. -There is a chance (20-30%) for very light snow Tuesday, but otherwise he probability for measurable precipitation is low. Split flow pattern with a trend is shown to continue through the long term periods, with a trend towards rising heights aloft which increases the potential for above average temperatures. Spread in NBM 25th and 75th temperature ranges increases significantly next week as would be expected in a more progressive pattern. The variability and weak nature of the northern jet stream also creates a large spread in and lower consensus on precipitation chances. There is one progressive wave resolved Tuesday that has a better chance to bring light accumulations to our region (20-30% for measurable), but the probability for 1" or more snowfall is less than 10% based on a combination of ensemble systems. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) Issued at 525 AM CST Sat Nov 25 2023 VFR conditions should prevail through the early evening across eastern ND and northwest MN, with southwest winds gusting during the daytime period 20-25kt mainly in eastern ND. A cold front arrives tonight and areas of light snow will overspread the region causing prevailing MVFR conditions initially. As northwest winds increase during falling snow, blowing snow could cause additional visibility reductions to IFR (possibly lower at times), but once snow clears the visibilities should improve. Behind the main area of snow there may be additional snow showers but coverage will be lower and impacts less certain (this is mainly an issue after the current TAF period for most sites in eastern ND). && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Perroux SHORT TERM...DJR LONG TERM...DJR AVIATION...DJR