Tuesday Night: Clearing. Low: 55

Wednesday: Mostly Sunny. High: 84

Wednesday Night: Mostly Clear. Low: 63

Thursday: Increasing Clouds. High: 88

Thursday Night: Overnight Rain Possible. Low: 65

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General Discussion:

Calm and mostly clear conditions are expected through Thursday afternoon. Because of these settled conditions and southerly winds, temperatures will be on the rise. Thursday night, increasing clouds are expected with chances of showers that last through Friday morning.  

-Jackson, Hayes, Schifferdecker

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Forecasters: Hayes, Schifferdecker, Jackson

Date Issued: 09/03/2024 5:00 PM CDT

Technical Discussion:

Key Messages: 

• High pressure throughout the low to mid levels of the atmosphere will persist through Thursday, leading to calm conditions across central Missouri. 

• Due to high pressure and a wind shift to the south by Wednesday afternoon, temperatures are expected to warm back up above average for this time of the year.  

• An upper-level trough will be shifting from the northwest to the southeast throughout this time period and will bring chances of rainfall late Thursday night into Friday morning. 

The NAM and GFS were used together in this forecast because they both generally agreed on the synoptic setup. 

Upper level moisture is being transported from the southwest to central Missouri, which is why an increase in cloud cover has been observed today. These clouds have limited the daytime heating throughout the day, which is why slightly cooler temperatures were seen in the afternoon hours. Although this upper level moisture is at play, cloud cover has been the only impact because low to mid level high pressure is in place over the Midwest.  

This high pressure will limit the amount of moisture in the atmosphere throughout the rest of the evening, leading to a decrease in cloud cover throughout the night. With a lack of cloud cover, radiational cooling will occur and temperatures will be allowed to drop into the mid 50s with the help of northerly winds by 12Z Wednesday. At 18Z, winds will make a shift into the south while the large high pressure system over the Midwest is still at play. Because of this, temperatures will reach into the mid 80s by 21Z Wednesday. This high pressure will continue to impact Missouri through Thursday afternoon, so similar conditions are expected throughout this timeframe. Further heating is expected to occur, which is why temperatures are expected to reach into the upper 80s by Thursday 21Z. 

A change in the synoptic setup arrives Thursday night as an upper level trough enters from the northwest. By 21Z Thursday, it will be positioned over Kansas and Nebraska, slowly shifting further southeast throughout the evening. Along the trough axis, there is disorganized mid level vorticity and lift associated with slightly better moisture than previously observed. The trough’s axis shifts further southeast, and by 06-12Z Friday, the components (vorticity, lift, and moisture) will be centered over Missouri. These disorganized components will lead to an increase in rainfall chances late Thursday night through Friday morning, although rainfall totals are harder to come by. This is due to the limited total moisture in the atmosphere along with the lack of organization. Expected rainfall totals by 12Z Friday are a trace to .05” because of this.  

After this system moves through, strong cold air advection is anticipated to move into Missouri. Future forecasting shifts should be aware of this and expect a cooler weather pattern on the way.  

-Jackson, Schifferdecker, Hayes