Current Conditions at Sanborn Field

Wednesday: Overcast and rain. High: 43

Wednesday Night: Rain. Low: 38

Thursday: Rain. High: 44

Thursday Night: Sky clearing overnight. High: 34

Friday: Sunny and warmer. High: 60

Thanks to IconArchive.com for the icons! 

====================================================================

Discussion: 

A chilly and rainy midweek is in the forecast! Due to the passage of a cold front early Wednesday morning, temperatures will fall below the seasonal average. Precipitation will persist for much of Wednesday and Thursday before the moisture supply is depleted. Around 0.3" of rain is expected to fall between the time of issuance and the end of Thursday. To end the week, Friday will consist of warmer temperatures and decreased cloud cover.

- Macko

=================================================================

Forecasters: Kobielusz, Macko, Bongard

Date Issued: 3/23/2022 10:00AM CDT

Technical Discussion: 

The period for this forecast is from 15Z Wednesday to Friday evening. Both the NAM and the GFS were evaluated for this forecast; however, the GFS was chosen due to its more accurate portrayal of a low pressure system in northern Missouri and having a better handle on current temperatures. The main focus of this forecast period will be how long precipitation will persist along with precipitation amounts. Soundings were used to determine the timing of precipitation, as well as precipitation types. The NBM was consulted in forecasting temperatures and precipitation totals.

A deep, positively tilted trough has its axis stretching from western Texas to northeastern Illinois. The low associated with this is currently in the Central Plains. This extensive trough is causing an exaggerated meridional pattern. A jet streak is just to the south of Missouri on the eastern side of the trough. As the trough, low pressure system, and jet streak continue to push east, Missouri sees a drastic change in wind direction. Upper-level winds start out southwest but shift to the northwest in the early hours of Thursday morning. Mid-Missouri then falls under the influence of another upper-level jet streak as the day progresses on Friday. Divergence is minimal throughout the forecast period until late in the day on Friday.

There is still a strong presence of meridional flow at the 500-mb level. This flow will, again, becomes zonal throughout the forecast period. An enhanced area of circulation is currently stationed over mid-Missouri along with a mid-level low. This low and vorticity moves east throughout the day but is quickly replaced with another mid-level low with more vorticity overnight Thursday. Areas of circulation continue to come and go in waves throughout the day on Friday.

The trough and low pressure are still evident into the lower levels of the atmosphere, although the low is more to the north, now located in Iowa. Moisture is currently prevalent in Missouri and will remain until late Thursday evening. As the low pressure continues to push east, Missouri falls into a northerly wind flow. These northerly winds will begin to dominate and push any moisture out of Missouri on Friday.

In the lower-levels of the atmosphere, a closed low can be seen over the Middle Mississippi Valley. There is still a strong meridional flow, but Missouri stays out of the influence of any jet streak until Friday. Early Friday morning, a lower-level northerly jet streak behind the associated cold front moves into Missouri from Canada bringing in drier air and helps to push any remaining moisture out. Missouri then stays within this jet streak for the remainder of the forecast period. Despite CAA residing over the area the lack of cloud cover will help to warm the high temperature to the low 60's Friday.

Soundings indicate that rain will persist throughout the day today as there is a deep moisture profile along with a note-worthy amount of negative omega at the surface. Omega becomes less significant overnight into Friday and moisture at 700mb and the surface begins to dry out. There is still moisture at 850mb, indicating that there could be some clouds overnight. Moisture continues to decrease as the sun rises on Friday leading to a clearing sky; however, moisture at the surface and calm wind indicates there could be the possibility for fog early Friday morning. Rain will be the dominate precipitation type but with cooling temperatures there could be the possibility of a snowflake or two Thursday night. Rain is expected to be off and on for the next few days but should come to a complete stop just after midnight on Friday. Rainfall totals for the forecast period will be around 0.33”. Future forecast shifts should continue watching for changes in rainfall totals as well as the potential for fog.

 

-Kobielusz