Current Conditions at Sanborn Field

 

Thursday Night: Mostly Cloudy. Low: 48

Friday: Partly Cloudy. High: 70

 

 

Friday Night: Light Showers. Low: 49

 

 

Saturday: Partly Cloudy. High:68

 

 

 

Saturday Night: Clearing to Mostly Clear. Low: 43

 

 

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Discussion:

We expect to continue these seasonal temperatures into the weekend with a slight chance of showers Friday night. Besides that, mostly cloudy conditions expected to continue into Saturday.

-Labit

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Forecasters: Labit, Macko

Date Issued: 4/27/2023 5:00 PM CDT

Technical Discussion: 

The primary focus of this forecast is the likelihood of showers overnight Friday as well as how long these seasonal temperatures will be lingering. After comparing both upper-air observation to analysis as well as comparing location and intensity of current precipitation. Both the NAM and GFS have been handling the current and past condition quite well. Additionally, when comparing the two models against each other, they seem to be quite similar. Due to this both models will be used interchangeably during this forecast. 

A shortwave visible at all levels of the atmosphere is positioned over the mid-Mississippi Valley causing divergence aloft. The exact placement of the trough axis remains closer to the Bootheel of Missouri. Combined with circulation and saturation at all levels, moderate rain is expected into early Friday morning. This should only be for areas south of central Missouri because of dry air at the surface preventing any rain that might fall aloft from reaching the ground. 

This shortwave will fall apart as it decays off to the northeast being replaced by a deepening longwave trough Friday evening. However, the mid-lattitude cyclone associated with this shortwave will propagate into the Great Lakes supplying ample moisture at the 850-mb level. This will be the layer to expect most cloud development. In between this transitioning phase, high relative humidities and warm air advection will help support partly cloudy conditions through Friday. Then by early Saturday morning this longwave will bring additional moisture at the 700-mb level. When mixing with the surfaced based moisture, divergence aloft and circulation (which is a bi-product of diverging winds with the jet stream), could result in light showers. After consulting the NBM, accumulations near ~0.10" will be likely.

Continuing into Saturday evening/overnight, the trough at 250mb will continue to deepen creating a closed, upper-level low into the Southern Plains. While this will cause some issues with more active weather in the Southern Plains Saturday evening, central Missouri should only see cloud formation. High relative humidity mixed with warm air advection at 850mb will help influence that, but it'll be too dry aloft and near the surface for any chances of precipitation. 

By late Saturday night into early Sunday morning, the mid-lattitude cyclone located in the Southern Plains continues to drive into the Lower Mississippi River Valley. This, combined with the second midlattitude cyclone over the Great Lakes region, should help wrap the remianing moisture towards the east out of our area.

- Labit