272 FXUS63 KOAX 190534 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1134 PM CST Mon Jan 18 2021 ...Updated Aviation Forecast Discussion... .DISCUSSION... Issued at 246 PM CST Mon Jan 18 2021 Forecast Summary: Areas of light snow tonight shouldn't amount to much before a warming trend Tuesday and Wednesday. A downward trend in temperatures follows for late week into the weekend. And our next chance for accumulating snow returns for the weekend as well, with a couple of shots of snow or a wintry mix Saturday and Sunday. This afternoon and Tonight: A couple mid level shortwaves were causing areas of light snow this afternoon. One was drifting southeast through southeast Nebraska and southwest Iowa at mid afternoon. Generally very light snow was seen with this area, but brief visibility reductions to a mile or so were reported. Amounts were generally a trace as temperatures were above freezing so any light snowfall melted rather quickly. A second shortwave in South Dakota will continue its trek southeast this evening, and will bring another chance for some light snow to mainly the northern half of eastern Nebraska and western Iowa. Light snow could begin as early as 6 PM in northeast Nebraska, then pivot southeast before exiting to the east of western Iowa by 3 AM. Again amounts will be generally light, averaging a half inch or less. Tuesday and Wednesday: Warmer temperatures are forecast into mid week as mid level heights slowly rise in wake of yet another shortwave spinning through Iowa on Tuesday. Better mixing and more sunshine will help temperatures gain several degrees over today's highs. Then lowering surface pressures across the Northern Plains on Wednesday will induce southwest low level flow in Nebraska and Iowa. 850 temperatures rise about 10C between Tuesday afternoon and Wednesday afternoon, suggesting significant warming under plenty of sunshine. Highs near or above 50 are likely west of the Missouri River where snow cover will be minimal. Thursday through Monday: There is pretty decent agreement between longer-range models in overall flow pattern into the weekend before diverging early next week. Upper lows are forecast to develop over central Manitoba and the central/southern California coast by Saturday. Strong westerly jet in the Northern Plains and west-southwest flow in the Central and Southern Plains will result in a coupled jet structure in our region. Currently most model output suggests best lift in this regime will reside over South Dakota and perhaps northern parts of Nebraska and Iowa on Saturday. Temperature profiles at this time suggest snow will be the primary precipitation type. Continued warm advection ahead of ejecting trough from the southwest will maintain a chance for precipitation Saturday night and Sunday as well, but likely less organized than Saturday. Several inches of snow are possible as model QPF tops a quarter inch in our northern CWA, but will have to wait for further model runs to gain more confidence on exactly where the greatest potential will reside. Otherwise temperatures will be on the way down beginning Thursday when an initial cold front drops 850 temps back below 0C. Continued cool advection Friday, then clouds/precip Saturday and Sunday, will keep temperatures near or below normal for the most part through the weekend. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1130 PM CST Mon Jan 18 2021 MVFR to VFR ceilings continue across the region this morning with a few light flurries pushing through KOMA for the first hour of the TAF but should be out of the TAF sites by 07-08z. Otherwise, skies are expected to scatter out later this morning with VFR conditions expected throughout much of the day. Surface winds will turn to the northwest this morning with some gusts up toward 20kts at times. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Dergan AVIATION...Kern