Current Conditions at Sanborn Field

 

 

 

 

Wednesday: Partly Sunny. High: 82

 
 

 

Wednesday Night: Cloudy. Low: 65

Thursday: Morning Showers and Afternoon Storms. High: 76


 

 

Thursday Night: Mostly Clear . Low: 46

 

 

Friday: Partly Sunny. High: 65

 

 

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Discussion:

Our above-average temperatures will come to an end Thursday as a cold front moves through in the afternoon, bringing with it morning showers and afternoon thunderstorms. The first round of showers will begin around 10 AM and will provide on-and-off rain until the afternoon, when a line of storms will enter the area along a cold front. These storms are unlikely to be severe, however expect some thunder and wind gusts that could knock over a trash can or potted plants. After the passage of the cold front, our temperatures will cool into the 60s for Friday, close to the seasonal average high temperature (66 F).

-Clark

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Forecasters: Ritsema, Clark, Cochran

Date Issued: 4/19/2022 10:00 AM CDT

Technical Discussion:

 

This forecast primarily used the NAM due to its recent performance regarding the locations of surface features, such as low pressure centers, when compared to an observed surface analysis. 

Currently, mid-Missouri is under an upper-level ridge which can be seen at 250 and 500mb. High RH values at 850 mb in the western part of the state alongside WAA, the presence of both due to a 50-60 kt low-level jet originating from TX and the Gulf of Mexico, are contributing to cloud cover which will build in from the W throughout Wednesday. At the surface, there is a low-pressure center over the OK Panhandle which will track NE across KS and into WI and MI. This low pressure system and its associated cold front are what will drive the formation of showers and storms Thursday before dropping our temperatures from the 70s to the 40s. 

18z Thursday will see the 250mb trough build in to western MO. Ahead of this trough is high 500mb vorticity, first moving through mid-MO Thursday 15z. After the passage of this forst round of vorticity, it decreases before intensifying and becoming more widespread Thursday 21z. While most of the vorticity is in SE MO at 21z, mid-MO will still see some showers and storms. 

 

The possibility of showers and storms is helped by high amounts of 700mb omega colocated with high RH in mid-MO between 15z Thurs and 00z Friday. This, along with high RH and WAA across MO from Thurs 12z to 21z means that there will be sufficient mid- and low-level moisture and forcing for the formation of precipitation Thursday between 15z and 21z. Due to the decrease in vorticity after 15z before intensifying again before 21z, there will likely be two rounds of rain: one in the morning around 15z Thursday and one in the afternoon, around 18 to 21z, which coincides with the passage of the cold front.

 

Both of the times of interest, 15z and 18 to 21z, have high MUCAPE values of 1866 J/kg and 1566 J/kg respectively. They both have high 0-1km wind shear (over 30 kt) and a high Total Totals index of 59 and 58 respectively. We believe that the earlier round of precipitation will not be convective, however, due to the high surface-based CIN of -394 J/kg as compared to the afternoon round's -99 J/kg. A CIN of -394 J/kg will be almost impossible for late-morning storms to break through due to the lack of diurnal heating at 15z, especially without any forcing from a frontal passage. The afternoon round, in addition to having a much lower CIN, has the advantage of the coincident cold front passage, providing ample forcing. 

 

After the passage of the cold front between 18 and 21z Thursday, a slight cooldown due to weak surface-based CAA will drop our high temperatures from the mid-70s Thursday down to the mid-60s Friday.

-Clark