Tuesday, February 16, 2021

 Current Conditions at Sanborn Field

Winter Weather Advisory in effect on Wednesday, Feb. 17 from 12:00 AM until 6:00 PM CST.

Tuesday Night - Clear in the evening. Mostly cloudy by morning. Low: 2-6

Wednesday -  Cloudy. Snow starting around sunrise. High: 20-24

Wednesday Night - Mostly cloudy. Lingering snow flurries early. Low: 6-10

Thursday - Partly sunny. High: 22-26

Mostly sunny. High: 24-28

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Thankfully, this week will bring us a much needed break from the extremely low wind chills we have been seeing for the past couple of days. Some of those cold temps will be lingering in the area tonight due to the persistent sunshine we had throughout the day today. However, increasing clouds and snow will return Wednesday morning and will persist throughout much of the day, ending in the early evening hours. Snow totals will amount to around 1-3 inches. A Winter Weather Advisory will be in effect starting from 12am on Wednesday and ending at 6pm that evening due to cold wind chills and expected travel conditions due to snow. Mostly sunny skies and closer-to-average temperatures will return on Thursday and Friday and will provide us with a much needed break from snow.

Forecaster: Clemons, Orr, Vochatzer
Issued: 5:00 PM CST 16 February 2021
Technical Discussion (The nerdy stuff we are discussing in class):

The GFS was the primary model used for this forecast since it seemed to provide more accurate temperatures than the NAM and other main models. SREF and GEFS plumes were consulted for forecasting temperatures, and current surface maps were referred to in order to get an up to date visual of what is going on right now.

At the 250 mb level, 12z GFS plots of wind speed and geopotential heights displayed an upper level trough being the dominant pattern over the region during the forecasting period. Central Missouri is in the exit region of the trough until around 6z Friday, when the trough passes through the area. 500 mb plots of vorticity show that the vorticity associated with this trough is most present Wednesday night and into Thursday morning. As the trough moves through, abundant vorticity is present in southern states such as Louisiana and Texas, but lacking in Missouri, leading to the clearer skies seen on Thursday and Friday. The vorticity seen in Missouri late Wednesday and into Thursday would suggest that the precipitation seen early Wednesday should continue, but lack of moisture in the lower levels prevents this from happening. 

700 mb plots of relative humidity demonstrate exactly why central Missouri’s precipitation event ends Wednesday afternoon. By 0z on Thursday, the abundant amounts of moisture will move out of the area, meaning Columbia will have cloudy overcast skies, but no more accumulating snow for the time being. At 850mb, wind plots show that Missouri will be cut off from the LLJ, providing another reason as to why Columbia will see clearer skies and no precipitation at the end of this forecast period.

QPF totals provided by the GEFS plumes suggest that central Missouri should have about 0.15 inches of precipitable water. With a standard liquid to snow ratio of around 10, that suggests that Columbia will receive about 1.5 inches of snow on Wednesday. However, the Midwest’s extremely cold temperatures caused the snow to liquid ratio to increase, as was seen with Sunday and Monday’s snow events. The same thing should happen in this scenario as well, putting Columbia in a range of 1 to 3 inches of snow. 


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