Current Conditions at Sanborn Field

WINTER STORM WARNING REMAINS IN EFFECT UNTIL 9 PM CST THURSDAY

Thursday Night: Sky clearing through the night with snowfall ending at 9pm. Low: 4

Friday: Sunny sky. High: 36

Friday Night: Clouds building overnight. Low: 22

Saturday: Partly cloudy. High: 36

Saturday Night: Clearing sky. Low: 30

 

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Discussion:

    The winter storm will exit the region tonight, leaving bitterly cold conditions in its wake. Columbia has already recorded half a foot of snow and more accumulation is possible this evening (up to 1-3”). Lows will be dangerously cold as the snow ends with wind chills falling below zero Friday morning. Temperatures recover nicely though as we reach above freezing in the afternoon so road conditions should be able to improve. A low pressure system passes through the Great Lakes region heading into Saturday and will bring clouds and slightly cooler temperatures to Mid-Missouri. Another system following roughly the same track will then usher in steadily warming temperatures to end the weekend.

- Splater

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Forecasters: Noblitt, Splater, Vochatzer

Date Issued: 2/17/2022 5:00PM CST

Technical Discussion: 

 

For our forecasting period, the GFS20 and NAM40 were compared to the 18Z surface analysis from the NWS. Both models accurately placed the lows over the Missouri Bootheel and up through the Ohio Valley as well as the highs over the eastern edge of the Missouri Basin and the West Coast. Additionally, the GEFS and SREF plumes were close to the temperature recorded at Sanborn at the time of writing, with the SREF plumes having a slight warming trend as each run was produced. Both models suffered from poor certainty in the Thursday low. With all this in consideration, both models were utilized for analysis and temperature forecasting, with the addition of the NBM to help focus the temperature spreads. GFS and NAM soundings were consulted for cloud cover.

First, looking at the 250mb plot of heights and winds, a large jet streak spanning from the South-Central CONUS up to the Great Lakes dominates our atmosphere aloft. This jet streak migrates to our southeast as an upper-level trough pushes in from the Missouri Basin at 6Z Friday. Following this we have mostly zonal flow until 3Z Saturday when a jet streak stretching from central Canada into the Missouri Basin. This jet streak will remain to our north, sliding over the Northern Mississippi Valley from 3Z to 18Z Saturday. After that we return to a more zonal flow for the duration of the forecasting period, ending with jet streaks to our north and south.

Next, as we observe the 500mb plot of heights, winds, and vorticity, a large band of circulation remains directly over Missouri until 0Z Friday. This is quickly followed by a second band of circulation traveling through from 4Z to 5Z Friday. Unfortunately, no further significant Vorticity is anticipated for the Mid-Mississippi Valley for the remainder of the forecasting period. Our winds remain mostly zonal for the remainder as well.

Following this up with the 700mb plot of heights, omega, and RH, we see little to no upward motion over central Missouri after the band aiding our current snowfall and cloud cover transitions to our east at 21Z Thursday. There is some spotty omega seen over the Mid-Mississippi Valley from 21Z Friday to 12Z Saturday. This could help to produce some cloud cover as this overlaps with a band of high RH curving down from the Missouri Basin. More omega can be seen moving into our region 3Z Sunday, however drier air is carried along with it so little cloud cover is to be expected for the rest of the forecasting period.

As we move on to the 850mb plot of heights, winds, temperatures, and temperature advection, our winds will remain out of the north as the cold front that produced our current snowfall goes east. However, a surface low traveling across the Canadian-US border moves east along northern Minnesota and into Michigan at 18Z Friday, which will rotate our winds out of the west with occasional shifts to the west-southwest, giving us some slight WAA. This is followed by a cold front extending west of the low trekking down onto the Missouri-Iowa border at 6Z Saturday. As this front continues to move southeast, our winds return to the north along with some CAA. At 18Z Saturday, a surface high migrating along the southwestern CONUS moves into Arkansas. This will rotate our winds to the west and into the southwest where they will remain for the remainder of the forecast.

Soundings indicated continuing precipitation and cloud cover until 3Z Friday. Based on QPF from both sets of plumes as well as guidance from the NBM, anticipated snowfall is expected to be about 1.5 inches for our forecast period, with all of it occurring at the beginning.

Future forecasters should pay attention to the plumes as there is some disagreement to the anticipated warming near the end of the weekend.

- Noblitt