561 FXUS63 KFGF 130528 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 1128 PM CST Sun Jan 12 2020 .UPDATE... Issued at 1005 PM CST Sun Jan 12 2020 Still seeing light returns on radar with occasional reports of light snow (likely just flurries). Still several enhanced regions of WAA supporting this activity though more organized vort max has tracked north of our CWA lowering confidence in measurable. Still minimal travel impacts tonight (at most) where light snow occurs. Still monitoring potential for dense fog development into the Devils Lake basin (maybe a little further east) late tonight into Monday morning. Moisture pooling from southeast flow converging near surface trough could support this and short range consensus still favors increasing fog coverage in our west late tonight. Still, not seeing upstream trends of fog (only stratus) lowering confidence. This would be more of an advection type fog event, so the sustained winds 10-15 mph shouldn't be as much of a limiting factor. I increased mention to "areas" for fog in my west, but still am not certain about dense fog development/coverage. Will be something to monitor closely overnight as this could cause travel impacts Monday morning. UPDATE Issued at 552 PM CST Sun Jan 12 2020 WAA continues to support pockets of flurries maybe a few clusters of light snow capable of a brief dusting. As trough axis shift east more organized pockets of forcing either track along International Border or split around our CWA, but I can't rule out these flurries/light snow showers lingering past this evening in axis of WAA. Expanded mention of flurries and adjusted PoPs to reflect current trends from radar/obs. Minimal impacts from any of these showers expected. Other focus will be small area of low stratus in SD that is starting to spread northward and matches up well with short range guidance which spreads this northward into our CWA and may eventually lead to an axis of fog across our west late this evening. Guidance indicates that where this is developing eventually deeper moist advection in southeast flow will support fog development and this was already added to the forecast previously. I adjusted timing and location of fog a bit to reflect current trends. There could be travel impacts if dense fog develops as indicated by some guidance, but so far there has been no indication of fog development within that area (yet). Will have to monitor trends this evening. && .SHORT TERM...(This evening through Monday night) Issued at 242 PM CST Sun Jan 12 2020 Breezy southeast winds will tame some after sunset with temps this afternoon in the teens above zero slightly cooling into the single digits above zero. Temps don't crash tonight as low level WAA will increase cloud cover. This is due to a developing lee troughing in the High Plains of the western Dakotas. A weak surface trough drapes over central ND and weak WAA near or ahead of the trough is producing light snow showers with some minor convective help. Another small system producing snow is moving east out of the Central Plains into the Upper Mississippi Valley. The majority of this snow is forecast to move through southern MN, although a small sliver of the CWA in west-central MN may see some flurries or brief light snow before midnight tonight. Neither activity is expected to produce accumulation. Some fog will be possible overnight tonight in the Devils Lake basin. The lee troughing in the High Plains continues to develop and move east on Monday as a mid level wave rounds the base of an upper low anchored in the Canadian Prairie Provinces. This will develop a surface low in northwest MN by Monday night bringing the next chance for snow. Most of the CWA has a chance of seeing snow for the later half of Monday through Tuesday. Snow accumulation is expected to be generally light, between 1-2 inches, although northwest MN is liable of seeing 3 or more inches as the low deepens. There continues to not be much appreciable signal for mesoscale forcing with this Monday night system, save some pockets of progressive low level fgen and initial conditional instability. .LONG TERM...(Tuesday through Sunday) Issued at 242 PM CST Sun Jan 12 2020 Tuesday through Thursday... A broad but muddy H5 trof should shift across western and central NOAM through Tuesday, allowing a reinforcing low level cold pool to slide into the area from western central Canada... bring cooler temperatures along with periods of light snow or flurries both days. Light snow should pull out of the area during the forenoon on Tuesday, with skies briefly clearing Tuesday evening and overnight ...then clouds increasing again on Wednesday for another batch of light snow. With accumulating snowfall expected both Tuesday and Wednesday, and with partially clearing skies possible for both evenings... overnight temperatures should plunge well below zero, with daytime temperatures on Wednesday and Thursday likely to remain near or slightly below zero. Windchill early on Wednesday and Thursday mornings could range from minus 25 to minus 35 degrees. Friday through Sunday... The H5 flow gains amplitude across the west for the late week period... with hemispheric models consistent in dragging a fairly strong short-wave trof through the intermountain west from late Thursday into early Friday... and through the central and northern plains from Friday into Saturday. The good news in that near surface temperatures should rise to near seasonal normals for Friday, as warm air build in aloft. However, a concurrent and deep moisture fetch through the southern plains states will likely produce heavy precipitation and snowfall from the central plains into the northern plains from Friday into Saturday. As mentioned in previous discussions ...the timing, placement, and amounts of precipitation for this late week system still show a high degree of variability, though our MN zones are most favored. Following the snow... Saturday into Sunday should see another sharp plunge in temperatures. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1128 PM CST Sun Jan 12 2020 MVFR ceilings have overspread eastern ND and northwest MN, and there are pockets of IFR ceilings starting to spread into southeast ND and west central MN (still south of KFAR). IFR should overspread all terminals by 12Z and prevail through the end of the TAF period. Potential is there for fog development into the KDVL area where LIFR ceilings appear more likely and vis may be reduced within IFR (if not lower) at times Monday morning. Less confidence in fog further east. Flurries also have bee n reported over parts of the region, but so far no impacts reported at any terminals (can't rule this out through midday Monday). Better snow chances start arriving closer to the end of the TAF period, but for now I left mention out as details are still uncertain. WInds will remain out of the southeast generally 5 to 12kt through the TAF period as low pressure remains just west. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...DJR SHORT TERM...CJ LONG TERM...Gust AVIATION...DJR