Thursday, November 4, 2021


Current Conditions at Sanborn Field


Clear. High: 53


Thursday Night:
Starry Night. Low: 35


Clear. High: 55


Friday Night:
Mostly Clear. Low: 37


Sunny. High: 62

Thanks to for the icons! 


   Good news for those who enjoy warmer weather! As the high pressure system moves to our east, the winds will become more southerly bringing those warmer temperatures. Stronger winds on Friday, particularly to our west, will allow the region to warm into the lower 60s for the high. The warming trend continues into the weekend, but expect chilly temperatures in the mid to upper 30s in the morning due to high pressure and a clear sky at night. Enjoy the warmer temperatures through the beginning of next week.

- Duff


Forecasters: Aldrich, Duff, McDonald

Date Issued: 11/04/21 8:30 AM CST

Technical discussion:  


The 06z NAM was used to forecast today, as it initialized current conditions more accurately, and was less bullish in developing the shortwave trough over the southeast this weekend.

At the highest levels of the atmosphere, Missouri is initially placed under the back end of a jet streak associated with a weakening trough at 250 mb, but it moves eastward out of the state by 18z Thursday. No further systems enter the region, with a continuous flow of northwesterly winds as cold air flows in. Further jet streaks graze the state on Saturday at 9z, but they are primarily situated to our north and south and do not interrupt our zonal flow.   

Very little vorticity is present on Thursday, with some lower values observed at 18z before a trough centered over Michigan moves further east. Thereafter, vorticity is almost entirely absent at 500 mb, with nearly no signs of advection for the next 72 hours. The midwest in general sees little activity in this field, as high pressure over Mexico continues to strengthen and increase it’s influence over the southern United States. 

700 mb relative humidity will remain low through the next few days as well. Winds are still showing a northerly component that should keep conditions on the drier side. Humidity is very high in the Gulf of Mexico at 12z on Friday, but it moves further eastward with a developing trough in the southeastern part of the country. Omega values are similarly very low, though they begin to increase at 00z Sunday. Any advection signalled by this would be warm air advection, as indicated by stability shown at higher levels through other variables.  

Temperatures at 850 mb will start to slowly increase on Thursday, as high pressure over St. Louis will begin to lurch eastward, shifting mid-Missouri’s winds into a more southerly flow by 14z Friday. The dissipation of this high into Saturday afternoon will correlate with the strengthening of a much larger HPS over Mexico and Texas, shifting winds to the southeast and bringing in much warmer air to Missouri at 00z Sunday, likely bringing a considerable increase in temperatures for the following day. 

GFS soundings display very dry conditions for the moment, and models indicate that they will only become drier and more stable over this weekend. 

Future forecasters should pay attention to increasing omega values on Sunday and the strength of high pressure over Mexico the weekend. 


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