Current Conditions at Sanborn Field

 

 

 

Friday: Few upper level clouds, increasing clouds in the evening. High: 40

  

Friday Night: Mostly Cloudy. Low: 30

 

Saturday: Partly Cloudy. High: 52

Saturday Night: Partly Cloudy. Low: 42


 
  

Sunday: Mostly Cloudy. High: 59

 

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Discussion: 

Highs for this weekend are once again above average for the season. Friday night the winds shift from the east to the north which will have our low slightly below freezing, however Sunday the winds will back to the south which will help bring up our temperatures into the upper 50's. 

-Allen

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Forecasters: Sallot, Allen, McGuire

Date Issued: 2/23/2023 10:20 AM CST

Technical Discussion:

 

 

The main concern of this forecast is the possibility for precipitation Friday night and the incoming low pressure system at the end of the forecast period.


The forecast area sits in the right entrance region of a jet streak until about Sun 21Z. For Friday, this jet streak position encourages divergence aloft. At 500mb, a shortwave passes through northern IA overnight from about Fri 21Z to Sat 6Z. While this shortwave is north of the forecast area, it will bring upper level clouds and light precipitation Friday night.


Despite the upper level clouds and plentiful moisture at 700mb and 850mb on Friday night, there is a significant dry layer in the mid levels of the atmosphere and a dry layer near the surface. As such, any precipitation Friday night will likely be very light, if it reaches the surface at all. This saturation and possible precipitation is expected around 00Z to 03Z on Saturday. Above freezing soil temperatures Friday morning, coupled with a daytime high of 40F, the ground temperature will not be cold enough for freezing rain, so the expected precip type is rain. Confidence is low in any of this precip reaching the surface due to the dry near surface layer.


A weak high pressure system in IA and southern MN on Friday leads to northeast flow at the surface for the forecast area all day on Friday and overnight into Saturday. This wind flow will keep temperatures in the high 30s to low 40s on Friday.


Upper level flow remains fairly zonal until about Saturday 12Z, when it shifts to a more southwesterly component. In the lower levels, a high pressure system over FL brings even more southerly flow to the forecast area. This should raise temperatures into the 50s on Saturday.


The next main concern for the forecast period is a deep trough approaching from the southwest US. As this trough approaches, flow at all levels becomes more southerly, bringing warm air into the forecast area, warming temperatures into the upper 50s on Sunday. The approaching trough and its associated cold front will reach the forecast area overnight into Monday. However, precipitation is expected to accompany this front, which may begin around 00Z on Monday. The next forecasting shift should be aware of this incoming through and precip.



Sallot