SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1233 AM CDT Thu Oct 14 2021 Valid 141200Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF OKLAHOMA AND THE MIDWEST REGION... ...SUMMARY... A few strong/marginally severe thunderstorms are possible later this evening across Oklahoma and this afternoon/evening over portions of the Midwest. ...Oklahoma... Broad upper trough over the western US will finally kick eastward by the end of the day1 period as an upper ridge builds into the Pacific Coastal region. Old frontal zone that is currently draped from MO-eastern OK-south TX should serve as the focus for convection through the period. Southwestern flank of the synoptic frontal zone will become more diffuse over the southern Plains ahead of the aforementioned short wave and surging High Plains cold front. By 18z a lee surface low should evolve over the TX South Plains, and this feature will then track northeast toward the Ozark Plateau region by sunrise Friday. Strong boundary-layer heating is expected across the southern High Plains extending into western OK by late afternoon. This should aid buoyancy for potential convective development, but forecast soundings suggest thunderstorm initiation may hold off until early evening due to weak capping. However, in response to the approaching trough, sustained moistening at 850mb is expected to result in substantial buoyancy if lifting a parcel at the top of the boundary layer. Latest thinking is scattered robust elevated thunderstorms will develop after sunset then track east-northeast during the overnight hours with some potential for hail. ...Midwest... Very moist PW plume currently extends across south TX into the mid MS Valley region along/east of the frontal zone. Remnants of Pamela have progressed into south TX, and this is aiding a broad corridor of convection that extends downstream ahead of the wind shift. A weak disturbance is forecast to eject northeast within this plume toward the Midwest later today, and despite poor lapse rates, adequate instability should exist for a few robust updrafts. Given the forecast wind profiles across this region, there is some concern that gusty winds, or perhaps even a brief weak tornado, could be noted. ..Darrow/Moore.. 10/14/2021 Read more LIVE: spc.noaa.gov
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