Current Conditions at Sanborn Field

 

Wednesday: Clouds building in the afternoon. High: 49

 

Wednesday Night: Cloudy. Low: 27

 

Thursday: Overcast. Rain and snow. High: 37

 

Thursday Night: Snow. Low: 24

 

Friday: Snow ending. Cloudy. High: 33

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Discussion:

No wishcasting here, folks! Meteorological spring may have arrived last week, but forecasts with snow have yet to take their leave. Snow is expected to begin late Thursday morning. A wintry mix is possible in the afternoon as temperatures warm above freezing. By Thursday evening, snow will become the dominant precipitation type once again with snowfall continuing overnight. Snow will end by early Friday afternoon, but cloudiness and chilly temperatures will persist. Snow totals are expected to be around 1".

- Macko

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Forecasters: Kobielusz, Macko, Bongard

Date Issued: 3/9/2022 10:00 AM CST

Technical Discussion:

The GFS and the NAM were evaluated for today's forecast: ultimately, the 06Z run of the GFS was chosen. Both models were running similarly temperature wise, but the GFS was doing a better job in accurately portraying low pressure in Colorado which will eventually lead us to our problem of the day. The main problem for this forecast will be the timing of our next chance for precipitation along with precipitation types and amounts. Soundings were consulted to determine timing and type of precipitation and the NBM was consulted in determining temperatures and snowfall totals. The period of this forecast ranges from Wednesday, March 9th to Friday, March 11th.

A zonal flow in the upper-most levels of the atmosphere has mid-Missouri just on the outskirts of a jet streak. This remains throughout the forecasting period until late afternoon Friday where wind speeds begin to increase. An upper-level, positively tilted trough located in the Dakotas this afternoon will head eastward towards Missouri but will lose amplitude as it heads east. By the time it reaches mid-Missouri, only the northern remnants of the trough can be seen near the Great Lakes.

The same trough that was observed in the upper-levels can be seen in the mid-levels of the atmosphere. This trough, again, begins in the Dakotas and makes its way east; however, the axis of the trough does reach mid-Missouri. An excess of vorticity is associated with the axis of this trough. Vorticity comes and goes in waves over the next coming days, but as we head into ​Friday and fall under the influence of the trough, vorticity increases.

Vertical velocity is also following the same patterns that vorticity is following. Positive omega will come and go over the next 36 hours and will really begin to become prevalent as we head into Friday with the axis of the trough. Moisture at 700mb is minimal until overnight on Wednesday. Then, moisture will increase until Friday. With the existence of moisture, lift, and instability, we now have all the ingredients necessary for precipitation.

Despite winds coming out of the north, moisture at the lower levels is more extensive than at 700 mb. It does however follow the same pattern of increasing overnight. Soundings indicate the saturation of the atmosphere overnight as well. There is a deep moisture profile shown overnight through early Friday afternoon. Given the cold temperature profile and lack of a warm nose, the most likely type of precipitation is snow. Snow is likely to begin Thursday morning before the possibility of transitioning into a rain and snow mix. This will continue through late morning on Friday as a dry layer begins to infiltrate. As for snowfall totals, 0.5" to 1.0" can be expected.

Future forecast shifts should continue to pay attention to timing and type of precipitation along with temperatures as cloud cover and snowfall may bring temperatures down.

-Kobielusz