Friday, November 12, 2021

Current Conditions at Sanborn Field


Friday Night:
Partly cloudy
. Low: 28  

Mostly cloudy. High: 43


Saturday Night: Increasing clouds. Chance of precipitation. Low: 38


: Partly Cloudy. High: 47  



Sunday Night: Increasing clouds. Low: 32


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Heavy jackets should continue to be worn as crisp temperatures persist throughout the weekend. The current low pressure system centered over Wisconsin will drift to the east by Saturday, taking with it the blustery weather witnessed on Friday afternoon. This will make way for sunnier and calmer conditions, much to the joy of Mizzou Tiger fans wishing for some decent sunshine. However, the high and low temperatures will remain quite cool – below freezing temperatures are expected as the low tonight and the remainder of the weekend should see highs in the mid-to-upper 40s. The relatively sunny conditions will be short-lived as a second round of increasing cloudiness is expected for late Saturday night. A cold front will move through the area early Sunday morning along with a possibility of light showers. Rainfall accumulations should be about 0.1”, if any occurs at all.


Forecasters: Ethridge, Millsap, Travis

Date Issued: 11/12/21 05:00 PM CST

Technical discussion:  

The GFS and NAM models showed general consensus between the mapped heights and the GOES satellite data for the region, although both displayed the low pressure center over the Great Lakes region as too far to the east. However, the GFS had a better handling of surface temperatures and was therefore used for this forecast. The main problems for this period are very cold temperatures on Friday night as well as two separate troughs that move through the region on Friday and Sunday. 

At the 250mb level, Missouri sits in a longwave trough with a low pressure center off to the Northeast. This system is likely a big component of the frigid temperatures Missouri will see overnight as Northwesterly winds in the jet stream bring a blast of cold air to the region. This trough becomes positively tilted overnight and into Saturday morning with zonal flow returning to the area on Saturday afternoon. Another trough moves over the forecast area on Sunday accompanied by a jet streak Sunday night.

There is a great deal of circulation over the region that moves out on Saturday morning by 9am as evidenced by the 500mb map. We see another active area of circulation on Sunday as well, but this vorticity looks more short-lived. 

The 700mb map shows a large area of moisture accompanying the low pressure system sitting over the Middle Mississippi Valley through the Great Lakes. This moisture moves away late Friday night with Saturday remaining relatively dry until the overnight hours. As that second trough mentioned above moves in Saturday night, another area of moisture enters the area until Sunday morning. A brief dry spell falls over Missouri at the 700mb level, but moisture returns to the region overnight Sunday.

Again, the Middle Mississippi Valley and as far south as Oklahoma show very cold temperatures overnight on Friday at the 850mb level. Temperatures increase a bit on Saturday, but that cold air returns to the region overnight Sunday.

The GFS 12Z sounding shows possible light frozen precipitation overnight Friday, and another chance for precipitation on Sunday morning around 5am. Both bouts of precipitation look to be very light. Solenoids are over the region on both Friday night as well as Sunday morning, likely accompanying the passage of the troughs. Missouri also sits in a saddle point on Sunday as a potential frontal passage moves through the region Sunday morning.


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