Current Conditions at Sanborn Field 

 

Tuesday Night: Clear. Low: 71

 

Wednesday: Mostly sunny. High: 93

 

Wednesday Night: Rain beginning after midnight. Low: 59

 

Thursday: Rain ending. Partly cloudy. High: 70

 

 

Thursday Night: Mostly cloudy. Low: 54

Thanks to IconArchive.com for the icons! 

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

Discussion:

A break from the heat is expected later this week! Rain associated with a cold front passing through Columbia on Wednesday night will result in much more fall-like temperatures.

Macko

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

Forecasters: Macko, Meier, Simmons

Date Issued: 09/20/2022 5:00 PM CDT

Technical Discussion:

 

While upper-level ridging has been the dominating weather feature over the past couple of days, a cold front moving into the area late Wednesday will bring a temporary change of regime. The NAM12 and GFS20 were both consulted in the forecast process. Unfortunately, the deterministic models resolved the frontal passage rather differently. The NAM12 was the greatest player in this forecast's precipitation chances as it was more effective in representing the depth of moisture in the column. 

 

As just mentioned, upper-level ridging is evident aloft. The jetstream was found to be curling over the top of the ridge on Tuesday afternoon. However, this same ridge is expected to deflate by Wednesday night with a jetstreak developing over the Great Lakes. As for Missouri, the jetstream will remain just north of the MO-IA border as upper-level wind divergence begins impacting the northern portion of the state. Overnight on Wednesday into Thursday, divergence will begin to extend further south into the mid-Missouri area. By late Thursday evening, the upper-level ridging pattern is reintroduced as high pressure builds back in. 

An increase in vorticity and moisture is anticipated concurrently with enhanced upper-level divergence Wednesday evening. The pockets of vorticity will effectively vanish over Central Missouri following the frontal passage; something similar can be said about saturation in the mid-levels. 

Analysis of skew-T diagrams suggests that PWATs will exceed 1.5in during the Wednesday into Thursday overnight period with K indices nearing 40. Localized heavy rainfall is possible during this time period, but convection remains improbable due to an incredibly steep low-level temperature inversion and a lack of low-level forcing. Rainfall totals associated with the frontal passage are expected to be around 0.1" with cooler temperatures to end the work week. 

Macko