Current Conditions at Sanborn Field 

 

 

Friday: Mostly Sunny. High: 80

  

 

Friday Night: Partly Cloudy. Low: 59

 
 
 

  Saturday: Mostly Sunny. High: 83

 

 

 

   Saturday Night: Increasing Clouds. Low: 64

 

Sunday: Partly Cloudy. High: 80

 

 

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Discussion:

Summer like temperatures will be in place throughout the weekend accompanied by strong southerly winds. There is a fire risk today with the low relative humidity and strong southwesterly winds. Winds will gradually swing around to due South for Saturday and Sunday with increasing intensity, causing a steady increase in moisture that will reduce the fire risk as we head into Sunday.

- Peine

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Forecasters: Peine, McCormack, Aldrich

Date Issued: 10/21/2022 9:00 AM CDT

Technical Discussion:

 

A mixture of both the 06Z run of the of the NAM and GFS was utilized for this forecast. There was close agreement between the NAM and GFS with the only significant difference occurring on Sunday, where the NAM has more moisture in place leading to cooler temperatures than the GFS. We went with the GFS for Sundays forecast because it gradually advects moisture into the region, which seems to be a more likely scenario than the NAM, which abruptly advects moisture into our region. The problem of the day is the potential for critical fire danger this afternoon due to the strong southwesterly winds and low relative humidity.

At 250mb and 500mb, a zonal flow from the West to East is currently in place over the region along with a shortwave trough that is moving across southern Canada. At 250mb, the subtropical jet will begin to couple with the polar jet over the western CONUS Saturday night due to a deepening tough. Dry air is currently in place from 700mb down to the surface due to the strong southwest winds. At the surface, there is an area of high pressure located over South Carolina as well as an approaching cold front that is associated with the shortwave trough to our North. As this cold front approaches the region today, the pressure gradient will increase over our area due to our position between the two aforementioned features. This will lead to gusty southerly winds around 20kts at the surface today. With strong winds and dry air in place, there will be a heightened fire risk during the day today that will diminish after sunset.

 

As the trough deepens to our west, our winds will increase out of the south throughout the weekend allowing for increased moisture advection. Moisture will steadily increase as the strengthening trough moves closer into the Intermountain West by Sunday evening, which will cause cloud cover to increase Saturday night into Sunday. Temperatures will be well above average (avg. high 65) for the entire forecast period (Friday-Sunday) due to the strong southerly winds that will allow for significant warm air advection. On Saturday, with strong warm air advection and no cloud cover, temperatures will warm efficiently, allowing us to near 20 degress above average for a high. Increasing cloud cover on Sunday should decrease incoming solar radiation, which will keep temperatures from warming as quickly as they will Saturday. Regardless, Sundays temperatures will be well above average as well due to continued strong warm air advection.

Future forecasting shifts should monitor the potential for some beneficial rain due to the aforementioned deepening trough that should move near our area by the beginning of next week.

- Peine