Current Conditions at Sanborn Field

Tuesday: Clouds increasing throughout the day. High: 66

 

 

 

Tuesday Night: Clouds decreasing overnight. Low: 25

 

 

 

 

Wednesday: Sunny. High: 39

 

 

Wednesday Night: Increasing clouds overnight. Low: 23

 

 

 

Thursday: Increasing clouds throughout the day. High: 48

 

Thanks to IconArchive.com for the icons!

====================================================================

Discussion: 

A very strong cold front will be moving through mid-Missouri Tuesday evening dropping the well above average temperatures Tuesday afternoon to below freezing overnight. After the frontal passage, Wednesday looks to be colder than average eventually warming back up to normal on Thursday. 

 -Ritsema

 =================================================================

Forecasters: Ritsema, Clark, Baker

Date Issued: 11/29/2022 9:30 AM CST

Technical Discussion:

 

Due to Tuesday morning temperature accuracy, the GFS was the main model used in our forecast as NAM was 15 degrees off on the current temperature Tuesday morning. Although, the NBM was used to aid in the precision of the temperature forecast.

At 300 hPa,a coupled jet stream is currently situated over most of the central and eastern portions of the CONUS, along with it strong southwesterly winds. The polar jet is positively tilted over the Central Plains, transitioning to a negative tilt Wednesday at 03z. This occurs after the frontal passage in mid-Missouri keeping the more active weather to the southeast. Winds shift to the northwest on the backside of this trough funneling cool dry air into Missouri. Divergence is absent throughout the forecast period.

 

Plenty of vorticity is associated with this trough, but not so much the frontal passage. Elevated levels of vorticity can be seen behind the frontal passage between Wednesday 03z and 18z. It is only until Thursday afternoon when we begin to see weak bands of vorticity move back into the area which will lead to cloud cover Thursday afternoon. Like at the 300 hPa level, winds are from the southwest Tuesday, northwest after the cold front, returning to the southwest again on Thursday.

Moisture is not present at the 700 hPa level Tuesday along the cold front until it moves into the southeast portions of Missouri and western Illinois. After the cold front passes a band of moisture moves into the area, although, it most likely won't be enough to produce any precipitation. The absence of vertical velocity hinders the production of precipitation, yet there will be cloud formation. Wednesday is very dry as cool air from the northwest is being pushed into mid-Missouri. Winds then shift back to southwest due to a high pressure system moving through Arkansas, warming Missouri back to average levels.

A strong southwesterly low level jet, with winds reaching 70 knots, is the main forcing mechanism to the well-above average temperatures Tuesday. That quickly changes, though, after the back-end of the trough reaches the CWA. Winds shift to the northwest at 40 knots around Wednesday at 03z bringing in cold dry air from the Northern Plains. Thursday a wind shift to the southwest will bring along warm moist air allowing for cloud formation Thursday afternoon.

At the surface, the cold front can be seen passing through mid-Missouri between Tuesday 21z and Wednesday 00z. Winds are from the southwest on Tuesday, northwest on Wednesday, and from the south on Thursday. On Wednesday, expect a harsh cool down after the frontal passage, solenoids suggest rapid cold air advection after the front passes.

-Ritsema