The late evening of Monday the 24th into the morning of Tuesday the 25th featured one of the most intriguing snow events of the 2019-20 winter season within South Central Nebraska. While the majority of the 24-county area (including the Tri Cities) received little to no overnight accumulation, an intense/narrow mesoscale band dumped as much as 6-10 of wet snow on portions of Dawson, Gosper, Furnas and southwestern Harlan counties. Amounts this high concentrated within a swath no more than 10-15 miles wide, with totals tapering off to barely a dusting only a few miles on either side. Per several official reports (NWS coop observer/CoCoRaHS) and a few unofficial ones, some of the highest totals featured: 10 in Elwood, 9 nine miles north of Edison, 8 in Edison, 6-8 at Beaver City and 7.1 six miles southwest of Lexington. On the periphery of the main band, more modest amounts included: 4.5 in Cozad, 4 at Gothenburg and 3 in Cambridge. Despite the hefty totals within the primary snow stripe, the fact that this was a late night/early morning event and that winds averaged only 10-15 MPH through most of it kept travel impacts somewhat in check through roughly sunrise. However, north winds picked up as the day of the 25th wore on, with frequent gusts of 25-35 MPH combining with residual light snowfall to promote some drifting and reduced visibility.
Breaking down timing, the main event associated with the intense mesoscale band unfolded over primarily a 7-9 hour span, getting underway between 10 p.m. and midnight as spotty light rain transitioned to steady snow, and weakening/gradually sinking southward into Kansas between 5-7 a.m. In the mid-upper levels, the primary player was a potent shortwave trough diving into the Central Plains from the north-northwest, featuring a compact/intense closed circulation that peaked in intensity while traversing the local area (especially evident at 700 millibars). As the already-strong zone of deep convergence/frontogenesis intercepted a pocket of steep mid-level lapse rates, the pronounced mesoscale band blossomed, starting out oriented predominantly north-south but gradually pivoting more northwest-southeast in response to the movement of the parent system. At the surface, the relatively light breezes through the night resulted from the region temporarily residing within the heart of an inverted trough axis, before this boundary slipped south around sunrise and allowed stronger northerly winds to kick in. Temperature-wise, the wet nature of snow resulted from overnight readings holding up mainly in the low 30s F. From a forecast perspective this was a challenging event, as although it became increasingly evident 24-48 hours out that mesoscale banding might ensue, its eventual placement/intensity remained a major question mark until it materialized on radar. In the end, although forecasted maximum snow amounts proved to be significantly under-done, a good chance for at least 2-4 within the broader general area became apparent by the afternoon of the 24th, prompting the issuance of a Winter Weather Advisory.