Subj : MESO: Mesoscale Discussion 2059 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Dec 22 2022 12:28:14 ACUS11 KWNS 221228 SWOMCD SPC MCD 221227=20 ILZ000-IAZ000-MOZ000-KSZ000-221700- Mesoscale Discussion 2059 NWS Storm Prediction Center Norman OK 0627 AM CST Thu Dec 22 2022 Areas affected...northeast through west central Missouri and adjacent east central Kansas...southeastern Iowa and west central Illinois Concerning...Heavy snow=20 Valid 221227Z - 221700Z SUMMARY...A band of moderate to heavy snow with gusty winds may contribute to near blizzard conditions, at times, while spreading across areas around and southwest of the Kansas City metro toward the Hannibal/Quincy, Columbia/Jefferson City and Lake of the Ozarks vicinities through 10-11 AM CST. DISCUSSION...To this point the advancement of the sharp surface frontal zone has been more rapid southward into the southern Great Plains (beneath 40-50 kt northerly flow around 850 mb) than southeastward into the lower Missouri Valley. This appears likely to remain the case into midday, when the front is forecast to have surged across much of central Texas, while only approaching the east central Missouri into northwestern Arkansas vicinity. Atop the shallow, but gradually deepening cold surface-based air mass (including surface temps falling from above freezing to the single digits and sub-zero), a remnant warm (albeit sub-freezing) and dry layer lingers (roughly centered near 700 mb) across southern /eastern Kansas through the lower Missouri/middle Mississippi Valley vicinity. This is in advance of a band of moderate to perhaps occasionally heavy snow that has been supported by strong enough mid-level frontogenetic forcing to overcome the warm/dry layer. The Rapid Refresh suggests that this forcing may weaken as the intense mid-level short wave trough digging through the northern Great Plains takes on more a neutral tilt this morning. However, it is forecast to gradually become better aligned with frontogenetic forcing in the 850-700 mb layer, across west central into northeastern Missouri. Beneath increasingly difluent and divergent upper flow, this may be accompanied by a period of maximizing lift in the mid-level layers around -15C, most conducive to dendritic ice crystal growth and substantive aggregation before reaching the surface.=20 Although the dendritic growth zone is forecast to lower with continued significant lower/mid-tropospheric cooling, and precipitable water may tend to quickly decrease below .30 inches, at least a 1 or 2 hour period of heavy snow rates around or in excess of 1 inch per hour appears possible, as the evolving band of snow spreads eastward. While the more substantive strengthening of northwesterly low-level flow into the lower Missouri/middle Mississippi Valley will probably occur well in its wake, forecast soundings suggest surface gusts on the order of 25-30+ kts may still accompany this band, contributing to occasional sharply reduced visibilities in blowing and drifting snow. ...Kerr.. 12/22/2022 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!5qRK6nhf1ydLc1SIUZLVRmlKF2Wf_eu14P398lLNjkQx7xNRf-sMOEYEwbAL4DrycKWZOQzuk= uE3ljfLGPgRAQahHeM$ for graphic product... ATTN...WFO...LSX...DVN...SGF...DMX...EAX...TOP...ICT... LAT...LON 40669331 40649123 38529199 37639382 38119584 38839645 39429452 40669331=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .