Current Conditions at Sanborn Field

 

 

Monday Night: Mostly Clear. Low: 36

Tuesday: Increasing Clouds. High: 52

Tuesday Night: Cloudy with Showers Late. Low: 39

Wednesday: Rainy. High: 47

Wednesday Night: Cloudy with Scattered Showers.Low: 37

 

 

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Discussion: After a beautiful day today, temperatures become more seasonable on Tuesday and Wednesday, with showers moving in by Tuesday night. Although Tuesday and Wednesday will be wet, with periodic showers throughout, rainfall totals will fall between .25-.5". Keep your umbrella handy!

-Shaw

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Forecasters: Shaw, Russell

Date Issued: 03/06/2023 5:00 PM CST

Technical Discussion: 

    Sunny and unseasonably warm conditions come to an end Monday night as an active pattern sets up across the Midwest through the end of the work week. Several weak shortwaves will move through MO, bringing with them a steady light to moderate rain on Wednesday and Thursday. Due to data issues, the Euro was rendered unavailable for this forecast; however, both the GFS and NAM were in good general agreement with timing of moisture advection and shortwave passage, so both were used for this period. 

    Surface low pressure over IA and an associated corridor of strong WAA pushed highs up to 69F this afternoon at Sanborn Field, about 20 degrees above the average for early March. As this low moves off to the NE, a weak cold front will sweep through this evening, dropping lows down into the mid-30s. Still, surface ridging will help scattered clouds build into the region, keeping lows from falling further. 

    Generally zonal flow remains in place over MO in the upper levels, with the core of the jet stream remaining over the upper-Midwest on Tuesday. Mid-level ridging sticks around, though a subtle mid-level shortwave responsible for Wednesday's precipitation will begin to slide off of the southern Rockies. Surface winds shift from northerly to easterly by Tuesday afternoon, keeping highs from reaching above the low 50s. Forecast soundings indicate increased upper and mid-level moisture sliding in by Tuesday evening, though a relatively deep dry layer near the surface will keep rainfall at bay until late Tuesday night.

    By early Wednesday morning, the aforementioned SW and associated vorticity maximum will orient itself over MO. Adequate low and mid-level forcing and upper-level divergence will be sufficient for producing light but steady rainfall, with modeled hourly rainfall rates around .1"/hr sticking around until the early afternoon, when the SW moves off into the Ohio River Valley. While low-level moisture (and thus, cloud cover) will persist throughout Wednesday, forcing and mid-level moisture will decrease Wednesday afternoon, resulting in a brief hiatus in rainfall during this time. By the evening, yet another SW will move in, resupplying mid-level forcing and moisture. Consequently, rain will build back into the area, and will stick around through the end of the forecast period Thursday morning. 

     Rainfall totals for this period (now until 12z Thursday) should fall on the higher end of the .25-.5" range in Columbia, especially with hourly rainfall totals never exceeding .1 or .2"/ hr. Although conditions will clear up by Friday, future forecasters will want to keep an eye on a developing Colorado low, which could provide active weather over the weekend. 

-Shaw