Wednesday, April 22, 2020

Wednesday Night - Overcast and rainy w/rumbles. Low: 52-56

Thursday - Overcast, clearing late afternoon. High: 68-72

Thursday Night - Partly cloudy. Low: 46-50

Friday - Overcast with thunderstorms possible, especially in the afternoon. High: 64-68

Saturday - Decreasing clouds. Rain possible in the morning. High: 58-62

 Thanks to for the icons!

Tonight into tomorrow, the main concern is rain. There is a low-pressure system to the southwest of mid-Missouri, which is associated with a large mass of rain. This rain will enter the Columbia area and stick with us through the overnight hours. Some rumbles are also possible. As the system pushes off to the northeast, we will start to see some clearing Thursday afternoon into Thursday night. But sadly, these clear skies will not persist for long. Another low-pressure system will start forming over northern Texas late Thursday. On Friday, it will be centered over Arkansas, but that system will help bring in all the ingredients for another batch of rain and possibly even some thunderstorms. Rain will stick around into the morning on Saturday, and we will be left with clouds through Saturday evening. 
Forecasters: Vanderpool, Pauley,Ritter
Issued:  5:00pm: April 22, 2020
Technical Discussion (The nerdy stuff we are discussing in class)

The primary issue in the next 24 hours is a low-pressure system centered to our south over Oklahoma. Models continue to indicate that this surface low will shift eastward, tracking through OK, northern AR, and into the lower Ohio River Valley by tomorrow afternoon. South of this low, severe weather is ongoing in Oklahoma, Texas, and Louisiana. That severe threat will shift east tomorrow, missing mid-MO well to the south. 

In the short term, the surface low is featuring a large shield of precipitation that stretches from central OK and up into central KS, southern MO, and Arkansas. The rain has struggled to reach Columbia, but high-resolution model guidance indicates that this rain should build slowly into the area as we approach nightfall. Some ensemble guidance (the SREF and GEFS) project mean rainfall totals of 1-1.5 inches, but the hi-res deterministic HRRR, HRRRv4, and NAM 3km keep totals at lower values of 0.25 - 0.9 inches. Higher values are certainly possible, though it would likely require convection to achieve these higher amounts. The ensemble models suggest MUCAPE values in the 100 - 400 J/kg range, which could certainly support some heavy rain and/or scattered thunder. Thus, we have gone with a mention of thunder in the forecast, though the bulk of the activity should be stratiform rain, with a total QPF somewhere between 0.4 and 1.0 inch. 

Thursday morning, rain should be moving out. The clouds will take a little longer to clear, however, and may persist until mid or late afternoon. How long these clouds hang around will determine how warm mid-MO gets tomorrow. With an earlier clearing (midday), Columbia could see highs reach 70 or a bit warmer. With clouds persisting longer, highs may be kept in the mid-60s. 

Thursday night, expect clouds to be on the increase towards the dawn hours as yet another surface low tracks through the southern CONUS. Currently, it appears that the track of this low will keep mid-MO to the north of any severe threat, though the GEFS, SREF, and ECMWF do indicate modest MUCAPE of several hundred J/kg. This might be enough to once again produce thunderstorms, though these storms will likely not carry much of a severe potential. QPF totals remain up in the air, though this will become better refined as the system draws nearer. 

On Saturday, cooler conditions will build into central MO as cloud cover, leftover rain, and modest cold air advection work in tandem. Right now, it appears that highs will be within a couple degrees of 60. Dry conditions should persist from Saturday afternoon through the remainder of the weekend. 

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