Current Conditions at Sanborn Field

 

Wednesday: Mostly sunny. High: 77

 

Wednesday Night: Clear. Low: 49

 

Thursday: Building clouds. High: 73

 

Thursday Night: Rain beginning after midnight. Low: 45 

 

Friday: Rain. High: 50

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Discussion:

Take the opportunity to get outside these next few days as rain will return by the end of this week. Another day of spring-like temperatures is on the way for mid-Missouri! Temperatures today will be almost 20 degrees above average for this time of year. This streak of above average temperatures will soon come to a halt on Friday as a result of a passing cold front Thursday evening. This cold front will cause our temperatures to drop throughout the day on Friday and bring us our next chance for rain. Rain is expected to begin just after midnight on Friday and continue throughout the day. Rain could be heavy at times, but total accumulations will be less than an inch.

-Kobielusz

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Forecasters: Kobielusz, Macko, Bongard

Date Issued: 3/16/2022 10:00AM CDT

Technical Discussion: 

Thursday and Friday will likely bring rain to the mid-Missouri region as an area of low pressure currently situated over the central Rockies tracks eastward over the Great Plains. Thus, selecting the deterministic model that was best modeling this area of low pressure was pivotal. GFS successfully modeled the placement of the low over the Colorado-Utah border while the NAM pushed it further south. For this reason, the GFS 06Z run was chosen as the deterministic model for the forecast period ending late Friday. The NBM was also used to help resolve temperatures considering the deterministic models have had a strong cold bias as of late.

The Polar Jet follows a meridional flow pattern through late Saturday. The Central Plains remain outside of the Polar Jet's realm of influence until late Thursday afternoon. By this point in time, a deep upper-level, negatively-tilted trough has presented itself, with the trough axis extending from North Dakota south into Oklahoma. This trough will pass through mid-Missouri before a more zonal flow is established.

Virtually no circulation can be found over mid-Missouri before 00Z on Friday. In the hours before this time, increased circulation associated with the low pressure system pushes up against the Kansas-Missouri border. By 06Z Friday, significant vorticity is expected over the state of Missouri. This vorticity will persist into the weekend but after having weakened during the afternoon hours on Friday.

Initially dry, the 700-mb level will see an increase in moisture late Thursday afternoon, a result of a shift to SSW flow. Here moisture shall remain through late Friday. Large, positive values of vertical velocity associated with the low pressure system are found over Missouri beginning late Thursday. This lifting mechanism will help aid in the development of rain showers. This forcing will dissipate late Friday.

A weak low-level jet with southerly flow is expected to form to the south of Missouri ahead of the low pressure system around 06Z on Friday, introducing additional moisture an already near-saturated 850mb level. At the same time, a stronger low-level jet to the east of the low pressure system will beginning pulling cold air from the north into western Kansas and Oklahoma. This second low-level jet weakens after moving into Missouri, but this northerly flow will result in cooler temperatures heading into the weekend.

GFS forecasted soundings were used to further examine the moisture depth. A thin, moist layer above 850mb in addition to the presence of negative Omega may result in some low-level cloud cover throughout the day on Wednesday. A slight westward shift in winds at this level will cut off moisture overnight into Thursday before southerly flow dominates once again, resulting in a return to cloudiness on Thursday. It is not until after 06Z on Friday that significant moisture depth and quality is achieved. Moreover, as the area of low pressure moves over mid-Missouri, considerable low-level convergence is apparent, leading to more lift needed for precipitation. Surface convergence becomes less notable heading into the early morning hours on Friday but is still present nonetheless. The upper levels of the atmosphere will gradually begin to dry out throughout Friday, but moisture remains prevalent between 700mb and the surface. Since there is still a well-defined moist layer and lift, precipitation will likely continue heading into the afternoon on Friday. Consequently, the largest contribution to total precipitation accumulations will occur between 06Z and 18Z on Friday. Total rainfall accumulations are expected to be just under 1". 

- Macko