Based solely on wind chill values, South Central Nebraska endured one of its overall most significant, but brief cold blasts of the last 30+ years during these days shortly before Christmas, with the harshest wind chills focused between the evening of the 21st and the morning of the 23rd. Based on observations from the Grand Island ASOS (Central Nebraska Regional Airport), which reasonably represented conditions across the 24-county area as a whole, most of South Central Nebraska endured roughly five consecutive hours of extreme/rare wind chills around -40 degrees (F) or colder, around 30 consecutive hours of wind chills around -30 or colder (Warning criteria), and around 42 straight hours of wind chills around -20 or colder (Advisory criteria). The absolute worst wind chills occurred on the morning of the 22nd, during which time nearly the entire area saw values plummet into the -40 to -48 range, including airport ASOS readings as low as -48 at Ord, -45 in Hastings and -44 at Grand Island. Although some places (especially northern counties) faced similar to even slightly colder wind chills less than two years prior (during the significant, more prolonged cold blast of mid-February 2021), especially southern parts of the area likely hadn't experienced wind chills this brutal in over 30 years...since the winter of 1989-90! Digging a bit deeper into the comparison between the sheer magnitude of the cold/wind chills between this Dec. 2022 Extreme Cold event and the aforementioned Feb. 2021 event, this one was certainly driven more by strong winds and less-so by extreme ambient air temperatures. In fact, no official daily temperature records were set this time around per ASOS data at Grand Island/Hastings, with actual low temperatures across most of South Central Nebraska on the morning of the 22nd only bottoming out in the -10 to -20 range. As a result, these extreme wind chills were significantly driven by relentlessly strong north-northwest winds. During the entire 30-hour period that the Grand Island ASOS observed wind chills of -30 or colder (centered between the evening of the 21st and the early morning of the 23rd), sustained speeds averaged 20-30 MPH, accompanied by frequent gusts at least 30-40 MPH. Although most of the area saw wind chills climb to slightly warmer than -20 by mid-day on the 23rd (due to the combination of slowly-rising temperatures and decreasing winds), at least sporadic wind chills as cold as -15 to -20 persisted from the night of the 23rd into the morning of the 24th, after which time the final Wind Chill Advisory was allowed to expire. Interestingly, this brief-but-intense cold blast was actually followed by a steady warm-up into and beyond Christmas itself. Again referencing Grand Island ASOS data (generally representative of South Central Nebraska as a whole) the daily high temperature bottomed out at -5 degrees on the 22nd, but then steadily recovered to 9 degrees on the 23rd, 16 on the 24th and 41 on the 25th. In fact, less than a week after the brutal cold of the 22nd, highs soared to between the upper 40s-upper 50s on the 28th.
Although the bitterly-cold wind chills were certainly the main weather story in South Central Nebraska between the 21st-24th, the early part of this time frame also featured one of the area's first semi-impactful winter precipitation events of the season. To kick things off, much of the daylight hours on the 21st brought a light mix of snow/freezing drizzle, making roads at least somewhat slick. However, the main event transpired during the evening-overnight, as a west-southwest to east-northeast oriented band of moderate to briefly-heavy snow gradually marched across the area, developing slightly behind the leading edge of a powerful Arctic cold front. This main snow band first organized within northern/west-central counties mainly 8-10 PM and eventually exited far southeastern local counties mainly 2-4 AM. Although the heaviest snow only lasted around two hours at any given location, this was long enough to drop a widespread 1-2 (isolated slightly higher), with visibility commonly reduced to at least one-half mile at times thanks to strong north winds sustained 25-30 MPH/gusting up to around 45 MPH. Although falling snow moved out of South Central Nebraska before daybreak on the 22nd, the combination of residual blowing snow and the aforementioned extreme cold/wind chills made for a most unpleasant weather situation for the morning commute. Briefly touching on the meteorological background behind this Extreme Cold event, the aforementioned sharp Arctic front blasted through the area from north-to-south between the late afternoon and mid-evening of the 21st. During the day on the 22nd, the still strong (but slowly decreasing) winds were driven by a stout pressure gradient directed between a roughly 1011 millibar low centered over northeast AR/southeast MO (along the cold front) and a stout 1055 millibar high centered over MT.