Friday: Overcast with scattered showers. High: 66
Friday Night: Showers and storms, some possibly severe. Low: 35
Saturday: Clouds exit early. High: 47
Saturday Night: Cold and clear. Low: 32
Sunday: Warming up. High: 53
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Forecasters: Splater, Schneringer, Bongard
Date Issued: 12/10/21 10:00 AM CST
A wide blend of models was used for the forecast period due to numerous uncertainties. The GFS, NAM and RAP were all utilized to take multiple scenarios into account. Soundings from each model were also compared to determine specific conditions for the forecast.
A deep trough is expected to impact the region late this evening and bring a slight chance for severe weather to our area. Presently, a diffuse frontal boundary is lifting north across Mid-Missouri and producing fog and light precipitation. As the trough meanders eastward today it will push the front further north and accompanying WAA will lead to near-record level warmth. Dewpoints are also forecast to approach the low 60s as we dwell in the warm sector of a surface low. This will lead to a chance for more showers throughout the day.
By this evening the trough will begin to enter the Mid-Mississippi valley, dragging the surface low and its associated cold front through the region. Fropa is aimed near 03Z tonight as model soundings depict increasing shear (around 75 kts 0-6 km, 45 kts 0-3km) and PWATs approaching 1". This, coupled with modest CAPE values from the low 100s in the GFS and near 1000 J/kg with other models will be sufficient for storms, possible severe.
However, a modest capping inversion in place today may throw a wrench in this forecast. Heavy cloud cover and showers today may also aid in sustaining it. Models depict the cap eroding away by fropa, but if it remains and reduces convection, storms will become much less likely. Additionally, the richer environment for severe storms is centered to our east towards the Ohio Valley. Overall, the threat for severe weather remains conditional for the forecast period.
Behind this system comes much more seasonal conditions for early December. Enhanced northerly flow will drop temperatures near freezing overnight though lingering cloud cover should prevent more frigid conditions. Cold air advection continues through Saturday though temperatures will still manage to stay slightly above average. Clouds exit the region early Saturday and clear conditions continue as a ridge affects the area to end the weekend. This will lead to the return of markedly warm conditions for the season with more above-average temperatures next week.