593 FXUS63 KABR 020520 AAC AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 1120 PM CST Fri Jan 1 2021 .UPDATE... Issued at 839 PM CST Fri Jan 1 2021 Chopped a couple of counties off the western edge of the Dense Fog Advisory. Fog has shifted east this evening. UPDATE Issued at 509 PM CST Fri Jan 1 2021 Extended the Dense Fog Advisory through mid morning Saturday. Visibilities are expected to remain low across the east through the night before improving by noon Saturday. Then, redevelopment is possible Saturday night. && .SHORT TERM...(This Evening through Saturday Night) Issued at 334 PM CST Fri Jan 1 2021 The forecast challenge is areal coverage/duration of dense fog and low stratus clouds across northeast South Dakota and west central Minnesota, along with temperatures. Currently, it is sunny and winds are out of the west everywhere that fog and low clouds are not. Temperatures have warmed into the 30s to low 40s across this region (central and north central South Dakota). Where it has been cloudy and foggy (northeast South Dakota and west central Minnesota), temperatures are in the teens and 20s for the most part, on light and variable winds. A Dense Fog Advisory was issued earlier today and continues to evolve as the fog dissipates and/or shifts over the region. Guidance and the low level/near surface environment, for at least this evening, supports the continuance of the Dense Fog Advisory, so it has been expanded further south and east and extended in time to midnight CST tonight. Conditions over McPherson and Edmunds Counties have been showing marked improvement this afternoon, so those two counties were removed from the advisory. It's entirely possible that fog and low clouds are continuing into Saturday morning, before better mixing and some low level waa can finally scour out the low level moisture, fog and clouds. Otherwise, the short term forecast is a dry forecast. Low level thermal progs and guidance continue to support mild temperatures through Saturday night, which seems reasonable, while boundary layer winds have a westerly component to them. .LONG TERM...(Sunday through Friday) Issued at 334 PM CST Fri Jan 1 2021 Nothing has really changed in the out periods, since the mid-shift had a look at things. Models still show progressive split flow (a notoriously difficult flow pattern for models to resolve in the out period). One thing worth noting is that models are beginning to ramp up low level wind speeds behind a cold frontal passage Sunday night. 0.5km winds are now progged at 40+ knots. It's just a matter of how much can caa and pressure change force some mechanical mixing enough to mix the stronger winds down to the surface Sunday night into Monday morning. The forecast is dry until late Tuesday night into Wednesday. There has been some consistency in the models/ensembles for one of these systems moving in off the Pacific Ocean, and then splitting off and diving southeastward in the stronger southern branch flow of the polar jet/sub-tropical jet, to produce some light precipitation over the region. In-house pops/qpf/snow guidance suggests there is a slight chance/low chance probability of a little bit of light snow. Also watching the very end of the period for perhaps a little bit more precip chance. But, at this point, that is very low confidence/high uncertainty. Temperatures, for the most part, continue to look relatively mild for this time of year, with a little bit of colder air perhaps entering the fray Wednesday into Thursday with the mid-week precipitation potential. Again, as the previous shift pointed out, no real noteworthy bouts of cold air showing up in the models in the 7-day forecast, at the moment. && .AVIATION...(For the 06Z TAFS through 06Z Saturday Night) Issued at 1118 PM CST Fri Jan 1 2021 Terminals KABR,KATY,KPIR,KMBG IFR vsby will linger near KABR and KATY into Saturday morning before clearing. Look for IFR/MVFR fog to redevelop Saturday evening. KMBG and KPIR are expected to remain VFR through the period. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...Dense Fog Advisory until 10 AM CST Saturday for SDZ006>008-011- 018>023. MN...Dense Fog Advisory until 10 AM CST Saturday for MNZ039-046. && $$ UPDATE...Wise SHORT TERM...Dorn LONG TERM...Dorn AVIATION...Wise