Current Conditions at Sanborn Field

 

Monday Night: Increasing clouds, patchy fog. Low: 29
  

 

Tuesday: Cloudy. High: 44

 

 

 

Tuesday Night: Rain late, quickly switching to snow. 2-5 inches of snow. Low: 32

 

 

Wednesday: Wet snow, heavy at times. High: 35

 

 

 

Wednesday Night: Cloudy. Low: 25

 

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Discussion:

Some possible patchy fog under increasing clouds Tuesday morning, with highs in 40's ahead of our next big system. Rain quickly changes over to snow Tuesday night, with snow persisting through Wednesday mid-morning. Expecting snow totals between 2-5 inches. Drive carefully on your Wednesday morning commute!

-Shaw

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Forecasters: Max Shaw, Joe Russell

Date Issued: 1/23/2023 5:00 PM CST

Technical Discussion:

 

    Experiencing a brief lull in active sensible weather as ridging takes control for the next 24 hours. All eyes are focused on a low-pressure system forecast to eject out of the Colorado area, which will bring severe weather to the deep south and significant winter impacts to MO. Of concern with this particular system is the exact track of the surface low. We are currently calling for 2-5 inches of snow in Columbia, though any small deviation in the low track could bring this total up or (more likely) down. The NAM and GFS are in general agreement in moving the low across the MO Bootheel Wednesday morning, whereas the EURO has it significantly further south, closer to Memphis. Because the EURO has been trending north with time, we chose to use a combination of the NAM and GFS for this particular forecast.

     

      In the upper levels, the shortwave responsible for our dreary weather on Sunday is moving off to our east as weak ridging moves overhead Tuesday. By Tuesday evening, a potent shortwave moves across the plains into the Ozarks and MS river valley, taking on a negative tilt as it does so. This negative tilt aids in the development of a jetstreak and rapid intensification of the low across MO and IL. Because Columbia will be sitting under the right entrance region, there will be plenty of divergence aloft... and thus ample lift across the area. The shortwave will be out of the area by Wednesday afternoon before another subtle shortwave begins to move in at the end of the forecast period. 

     Strong mid-level forcing will be in place as the low moves across southern MO, which will certainly help promote bands of heavier snow, starting around 03z Wednesday. The GFS and NAM seem to show two enhanced circulations with a break in between, so there may be a lull in snowfall early Wednesday morning before things pick up again around the morning rush. This second circulation is associated with a fairly tight temperature gradient at 500 mb, so frontogenetic forcing may play a factor in increased snowfall rates with this second band. That being said, uncertainty does exist concerning how strong this forcing will be and how much of an effect it will have on snowfall rates.

     Low-level moisture is plentiful across the area, and it does not appear as though a lack of moisture or dry slot will manifest, which would lower snowfall totals. Moderate southerly winds ahead of the low will help keep this moisture in place. Additionally, a large area of WAA across southern and eastern MO will promote lift in the DGZ which lowers and increases in depth as the event continues. While the most intense WAA and forcing look to stay south and east of Columbia, values look impressive enough to warrant a few inches of snowfall.

 

     There are still several factors which could result in a busted forecast. As was aforementioned, there are discrepancies in the track of the low between the GFS, NAM, and EURO. The NAM takes the surface low ever so slightly north and west of the GFS forecast. While this difference is relatively small spatially, the low tracking several miles further NW could bring our snow totals from up 2-3 inches up to 4-5 inches. If the low were to move further SE, as the EURO would suggest, our totals would fall closer to 0-2 inches. Furthermore, ground temperatures are currently sitting around 40F. Even though heavy snowfall rates may overcome the melting rate, we still will likely see some initial snow melt. Finally, near-surface temperatures will be right around freezing throughout the duration of this event. This will be a heavy and wet snow, with snowfall ratios below 10:1. It's possible that we could see some rain mixing in early on in the event, which would also result in lower snow totals. Still, we feel confident that snow totals will be between 2-5 inches by the time everything is said and done. 

- Shaw