Storm Prediction Center Discussion
SPC MD 2238
MD 2238 CONCERNING HEAVY SNOW FOR PORTIONS OF EASTERN WISCONSIN INTO ADJACENT NORTHEASTERN ILLINOIS
Mesoscale Discussion 2238 NWS Storm Prediction Center Norman OK 0409 AM CST Thu Nov 21 2024 Areas affected...portions of eastern Wisconsin into adjacent northeastern Illinois Concerning...Heavy snow Valid 211009Z - 211345Z SUMMARY...An hour or two period of 1-2+ inch per hour snow rates appears possible early this morning, coincident with strong gusty winds resulting in blowing snow and reduced visibilities. This appears most likely to spread from near or just west of Green Bay southward through the Oshkosh vicinity and areas west of Milwaukee by around 8-9 AM CST. DISCUSSION...To the southwest of the lingering occluded surface cyclone over the upper peninsula of Michigan, sub-freezing thermodynamic profiles remain entrenched across much of Wisconsin, in the presence of strengthening lower/mid-tropospheric warm advection. This is occurring in advance of a southwestward then southward pivoting mid-level cyclonic vorticity center, which is forecast to be accompanied by strengthening northerly flow to 50-60 kt in the 850-700 mb layer across much of eastern Wisconsin. Associated strengthening of large-scale ascent is likely to continue contributing to saturation of thermodynamic profiles and the development of snow through 13-15Z. Models suggest that lift may become strong and focused near and just ahead of the mid-level cyclonic vorticity center, maximized within a layer near/above 700 mb with temperatures around -15C, and conducive to large dendritic ice crystal growth. It appears that this may be accompanied by a period of heavy snow rates on the order of 1-2+ inches per hour, coincident with strengthening, gusty surface winds. ..Kerr.. 11/21/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GRB...LOT...MKX... LAT...LON 45018918 44728772 43868764 42428826 43148946 45018918Read more