Mesoscale Discussion 0321 NWS Storm Prediction Center Norman OK 1018 AM CDT Wed Apr 07 2021 Areas affected...Parts of western/central Missouri and adjacent portions of eastern Kansas...northeastern Oklahoma and northwestern Arkansas Concerning...Severe potential...Watch likely Valid 071518Z - 071715Z Probability of Watch Issuance...80 percent SUMMARY...The initiation of strong to severe thunderstorm development appears possible by early this afternoon. A severe weather watch likely will be needed at some point, perhaps as early as Noon-1 PM CDT. DISCUSSION...In the wake of an initial weakening mid-level perturbation and associated thunderstorm development, the primary upstream short wave impulse is in the process of pivoting eastward across western Kansas/Oklahoma and northwest Texas, and forecast to gradually take on a neutral to negative tilt across the central Great Plains through 18-20Z. Between these two mid-level features, an area of enhanced lower/mid tropospheric warm advection may be contributing to renewed thunderstorm development near/above a remnant outflow boundary across the Lake of the Ozarks vicinity. There appears at least some potential for this activity to intensify through mid day, while spreading northeastward through central Missouri, perhaps aided by inflow emanating from a destabilizing boundary layer to the southwest. In the presence of at least modest cloud-bearing layer and shear, and steepening mid-level lapse rates, this may be accompanied by a risk for severe hail. However, the primary concern appears to be the potential for the initiation of vigorous thunderstorms within a corridor of strengthening deep-layer forcing for ascent, just ahead of the eastward advancing cold front approaching the western Missouri/Arkansas border vicinity. While it appears possible that this may occur as far north as areas near/northeast of the cold front/outflow boundary intersection (currently south of Kansas City), more substantive warm sector boundary-layer warming may remain confined to areas south through southeast of the Lake of the Ozarks. While the timing of this new thunderstorm development could wait until a bit later this afternoon, it appears possible as early as 17-18Z. Once this occurs, wind profiles including 30-50+ kt flow in the 850-500 mb layer, and modestly large and clockwise curved low-level hodographs, in the presence of mixed-layer CAPE in excess of 1000 J/kg, will be conducive to organized severe thunderstorm development. This includes the potential evolution of supercell structures capable of producing severe hail and, gradually, increasing risk for damaging wind gusts and perhaps a couple of tornadoes. ..Kerr/Hart.. 04/07/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LSX...LZK...SGF...EAX...TSA... LAT...LON 35839440 37629452 38129480 39229492 39789479 39689376 39429286 39379208 38669157 37319239 35999333 35839440
Storm Prediction Center Mesoscale Discussion 321
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