Monday, November 1, 2021

 

 

Current Conditions at Sanborn Field

 



Monday:
Cloudy. Spotty showers begin in the afternoon. High: 45



Monday Night:
Cloudy. Occasional showers. Low: 34

 


Tuesday:
Becoming partly cloudy. High: 47

 


Tuesday Night:
Becoming cloudy. Low: 33

 


Wednesday:
Cloudy. High: 47

 
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Discussion:  

Hibernation time has arrived! For the first time in what seems like awhile, we are seeing below average temperatures, as high pressure is creeping into our area. A low pressure system coming off of the Rocky Mountains will bring precipitation and cloud cover to the area beginning Monday afternoon. This will quickly get out of our way by Tuesday, as a high pressure system takes over. During this transition peaks of sunshine are possible by Tuesday afternoon, but will be followed with more cloud cover later this week. With cloud cover and winds mostly from the north, temperatures will stay in the mid 40's. Just in time to break out those winter jackets!   

-Baker

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Forecasters: Baker, Cade, Travis

Date Issued: 11/01/21 10:00 AM CST

Technical discussion:  

It's that time of the year for the Midwest, fall is quickly slipping into winter! Temperatures are dipping down to below average for the beginning of this week. The main concern for this forecast is rain following a mid-level shortwave trough and low-level frontogenesis Monday into Monday night. A High pressure system makes it's way over Missouri Tuesday into Wednesday, bringing with it some calmer weather. SREF and GEFS plumes were used for model diagnostics as GFS and NAM were operating similarly. SREF had a wider spread than GFS and seemed to be too cold when compared to observed temperatures. Therefore, GFS was used in this forecast.

Some divergence is present over the middle Mississippi valley at 250 mb for Monday into Monday night, leading to suspicions of active weather. Flow is meridional for the majority of the forecast, but a ridge begins to move in over the Western United States Wednesday into Wednesday night, moving towards the area on Thursday.

Vorticity exists at 500 mb for Monday night, adding to the suspicion of activity for Monday. Winds are mainly northerly, which is the trend for this forecast and part of the reason why temperatures are going to dip this week. Tuesday and Wednesday seem to have nothing going on, so there is no concern over possible precipitation.

At the 700-mb level, RH and Vertical Velocity values are high over the middle Mississippi valley, adding to the suspicion for rain Monday into Monday night. Tuesday morning, RH values begin to drop along with vertical velocity, which stays the same for the rest of Tuesday into Wednesday.

Northerly winds remain at both the 850 mb level as well as the surface, along with solenoids. This means CAA, which will bring temperatures down to below-average for the entire forecast period. Tuesday night, a HPS moves into the middle Mississippi valley and stays into Wednesday, ruling out any suspicions for precipitation, which was already low. The GFS sounding showed temperature and dew point lines inching closer together Monday Morning into Monday afternoon. This supports the idea of incoming cloud cover and rain for Monday. They move apart Tuesday morning and seem to stay for Tuesday and Wednesday, except for some high-level clouds and moisture left behind. Total Rain accumulations should only be around 1/4" for Monday.

-Cade

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