782 FXUS63 KOAX 061147 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 547 AM CST Mon Dec 6 2021 .UPDATE... Issued at 547 AM CST Mon Dec 6 2021 Cloud temperatures are favorable for snow crystals, so we added a mention of some flurries possible this morning. && .DISCUSSION... Issued at 305 AM CST Mon Dec 6 2021 Temperatures the next several days and the chance for some flurries or light snow late tonight into Tuesday morning will provide the main forecast challenges. Parts of the area could see rain or snow from late Thursday night into Friday night. The nearly zonal upper tropospheric pattern buckled yesterday and upper air charts from last evening showed the following. At 300 mb, a jet max of 155 knots was punching southeast from MT and WY, while winds at that level from WI into Canada were blowing to the northeast. At 500 mb, a shortwave trough was moving through the region, with 12 hour height falls in excess of 150 meters from eastern SD into southern MN. Much colder air was moving south across the northern half of the Plains at 700 mb and 850 mb, with -19 C noted at Glasgow at 850 mb. Surface analysis at 3 am showed low pressure over upper Michigan and high pressure over eastern MT. Colder air had penetrated down into TX. Temperatures were in the single digits above and below zero from eastern MT into ND and western SD. Our temperatures locally were in the 20s to lower 30s. Highs yesterday in the forecast area were in the 50s, but today will be much cooler. Northwest winds will remain fairly strong into early afternoon, then gradually decrease mid to late afternoon as a ridge of high pressure at the surface builds over the region. Temperatures will continue to slide down this morning with only a modest recovery this afternoon. Look for daytime highs in the 20s north and in the 30s south. Winds will turn to the southeast or south tonight and isentropic upglide should cause clouds to thicken and lower. Models show some modest omega values above 700 mb, but the low levels will probably remain fairly dry. Will keep a mention of flurries or a slight chance of light snow after midnight into mid morning Tuesday for parts of the area, but nothing measurable is expected. The chance for snow will be higher from eastern SD into southwest MN and possibly a small portion of northwest IA. The period from Tuesday afternoon through Thursday evening still looks dry. Temperatures will moderate through the period, with highs mainly in the 50s for Thursday. A front is forecast to push through the area Thursday but not have a big affect on temperatures. As a mid level trough develops over the Rockies, this will help strengthen a low pressure center at the surface over eastern CO. That low will then track quickly east across KS and MO Friday, reaching near the IA/MO/IL border by Friday evening. Precipitation is expected to spread eastward in a deformation zone from western NE across central and northeast NE. Several lifting mechanisms will come into play, including upper level divergence. Just how far south the snow gets is not clear, but it could affect much of the forecast area. At least for now, chances are highest north of Lincoln and Omaha/Council Bluffs, but that could change. Run to run model consistency has not been good, but the overall pattern is favorable for precipitation somewhere in the region. Expect a fairly large range of high temperatures across the area Friday, from upper 30s at the SD border to upper 50s near the KS/MO/NE border area. Temperatures will be critical for the type of precipitation and accumulation amounts, so that will be fine tuned over the next several days. Further out in time, expect a warming trend from Saturday (highs around 40 to 45) through Monday (highs from the upper 40s to mid 50s). There is some model spread, but the pattern favors mild temperatures with a trough digging to our west and increasing heights over the central US into Tuesday and possibly Wednesday. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) Issued at 518 AM CST Mon Dec 6 2021 An area of MVFR clouds is slowly dissipating as it moves through northeast Nebraska this morning. This deck has already reached KOFK, and could briefly stumble into KOMA with BKN coverage around FL025. A few flurries could fall under the lower clouds, however no accumulation is expected. Winds will remain gusty through about 18Z today, but will weaken through the afternoon and evening hours. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ UPDATE...Miller DISCUSSION...Miller AVIATION...KG