SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0734 AM CDT Tue Oct 19 2021 Valid 191300Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDDLE MISSOURI VALLEY... ...SUMMARY... Strong thunderstorms posing a risk for isolated severe hail are possible late tonight (early Wednesday morning) across parts of northeastern Nebraska and southeastern South Dakota into northwestern Iowa. ...Middle Missouri Valley including portions of NE/SD/IA... A closed low centered over Utah/western Colorado this morning will continue eastward and reach the central High Plains by evening. The progression of this system will influence modest surface cyclogenesis across Kansas/Nebraska in tandem with the sharpening of an eastward-moving cold front that will cross the region tonight into Wednesday. Pre-frontal moisture advection into the region will be modest overall given limited source region availability, but middle 50s F surface dewpoints could develop into the middle Missouri Valley late tonight. These forcing for ascent/moisture trends are likely to influence a nocturnal maximization of thunderstorms, with initial isolated development across northern Nebraska/southern South Dakota becoming a bit more numerous (scattered) into the overnight in areas near the front and near/north of the surface low, including northeast Nebraska/southeast South Dakota and northwest Iowa. Steepening mid-level lapse rates atop stable but moistening low-levels could support MUCAPE near/above 1000 J/kg. Owing to strong deep-layer southwesterly winds, very strong shear through the cloud-bearing layer could support some elevated supercells capable of isolated severe hail overnight. ..Guyer/Leitman.. 10/19/2021 Read more LIVE: spc.noaa.gov
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