Tuesday, October 22, 2019


Tuesday Night -  Partly Cloudy. Low: 39-43

Wednesday - Partly Sunny. High: 64-68

 Wednesday Night - Increasing Clouds. Low: 41-45

Thursday - Overcast. Showers Possible. High: 46-50

Friday - Clouds Early, Clearing Out Afternoon. High: 52-56

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Dry conditions are in the forecast for the next 24 hours. Tonight, expect mostly clear skies to transition to partly cloudy as the night wears on. Lows should bottom out in the upper 30s and lower 40s. Tomorrow, south winds will help to warm things up again, with mid to upper 60s likely under partly sunny skies. Tomorrow night into Thursday, our next weather disturbance will arrive. A cold front will drop temperatures Thursday morning into the low 40s, with overcast skies and rain showers keeping highs for Thursday likely remaining below 50. Friday, we should see clouds and rain move out, with sunny skies and chilly conditions by the afternoon. 
Forecasters: Heaven, Vanderpool
Issued:  5:00 p.m. ; October 22,  2019

Technical Discussion (The nerdy stuff we are discussing in class!)
WPC model diagnostics indicates a preference for general model blend, with above-average confidence. We will be using the 12z GFS for the majority of this forecast, with consideration also being given to the 12z/18z NAM 12km and the SREF.

Overall, it's a pretty active setup over the CONUS. A powerful, well-occluded surface low was situated over Lake Superior at 18z. This low was located within a very large 500mb trough that extended into the central CONUS. A 500mb jet max was noted over eastern Indiana and NW Ohio in association with that trough, helping to support an east-moving cold front running roughly along the eastern foothills of the Appalachian Mountains.This trough and accompanying surface low will continue to swing eastward with time, setting the stage for a fairly uneventful night in mid-Missouri.

Tomorrow, WAA returns, with GFS model-generated soundings indicating the majority of this WAA in the sfc-700mb layer. Thus, although we will warm up quite a bit tomorrow (mid to upper 60s, with some places possibly seeing 70), the warm-up will not be too spectacular. Also, both GFS and NAM indicate moisture present near the 850mb level, which should help to create some clouds throughout the day.

Wednesday night, another longwave trough swings into the Midwest, driving a powerful cold front down through Missouri. Temperatures with the fropa will drop as low-level CAA kicks in on its backside, thus lows Thursday morning will bottom out in the lower to middle 40s. The sfc front continues south through the day Thursday, but moisture advection at the 700mb layer and above will really help to saturate the atmosphere. This keeps Mid-Missouri in solid overcast throughout the day. Thursday night into Friday, a disturbance (as evidenced by 500mb and 700mb vorticity) reaches the base of the trough over mid and southern MO and provides lift to the saturated atmosphere. This gives us a good chance for some cold rain throughout the overnight hours. Clouds and rain for Thursday afternoon and Thursday night will keep temperatures down, with highs Thursday likely not breaking out of the 40s.

For Friday, upper-level winds finally switch around to the NW as the 700mb and 500mb trough axes progress east. This leads to a rapid scouring out of moisture by mid-day, ending the rain and overcast skies. Interesting to note here is that the NAM and GFS disagree on timing, with GFS pushing moisture out by late morning and the NAM keeping it through evening. If the NAM is correct, Friday will be much cooler and cloudier. However, GFS solution appears more likely for now, so sunny skies will likely prevail Friday afternoon, with light N winds.

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