Current Conditions at Sanborn Field

 

  Tuesday: Mostly Sunny. High: 57.
              

Tuesday Night: Cloudy. Low: 49

Wednesday: Thunderstorms in the afternoon, some may be severe. High: 64.

Wednesday Night: Clearing clouds. Low: 43

 

 

 Thursday: Sunny. High: 43

 

 

 

 

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Discussion: The beginning of the week will remain unseasonably warm! However, as a cold front passes through Wednesday afternoon. After this cold front passes, cold air will move into our area and high pressure will dominate.

-Meier

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Forecasters: Simmons, Meier

Date Issued: 2/21/2023 10:00 AM CST

Technical Discussion:

 

Unseasonably warm, spring-like temperatures will dominate for the early portion of the work week. A combination of the NAM and GFS was used since both models are mainly in agreement on the timing of the frontal passages. The biggest problem this week is the cut-off low pressure system that is currently in Mexico. This low-pressure system will bring us lots of precipitation along with the chances of severe weather.

In the upper-levels of the atmosphere, the Polar Jet and Sub-tropical jet are merging together off to the east. With this merging, there is a very strong jet-streak off to the east which is bringing us zonal flow. The cut-off low over Mexico will continue to move towards Missouri. Overnight Tuesday into Wednesday, this low-pressure system will be reabsorbed into the upper-level flow. After it is reabsorbed, is turns into a shortwave trough. As it gets closer to the midwest, this shortwave becomes negatively tilted right before it impacts mid-Missouri. Since it becomes negatively tilted, this will increase the likelihood of severe weather. Also, as this negatively tilted trough impacts the area, it brings in a lot of upper-air divergence which also increases the risk of severe weather. The divergence enters the region at 18Z Wednesday and is completely gone by 00Z Thursday. Once the system passes, zonal flow returns and high pressure dominates.

In the mid-levels of the atmosphere, we see the cut-off low become absorbed into the upper-level flow. Vorticity begins to build in at 15Z Wednesday. This vorticity continues to build throughout the day until the vorticity max passes over at 21Z. The same is true for relative humidity and omega. The atmosphere is dry in the mid-levels until 18Z Wednesday when the air begins to saturate to 100% humidity. Along with the humidity building in, omega builds in at 18Z and becomes very strong. The relative humidity along with the strong levels of omega will increase the risk of severe weather. At 00Z Thursday, all the vorticity, humidity, and omega will all leave the area. The area will then remain dry throughout the remainder of the week.

In the low-levels of the atmosphere, a very strong LLJ forms. The LLJ is right over mid-Missouri and will have winds over 60kts from the south. This LLJ will advect lots of moisture into Columbia, along with warm air. WAA will then occur overnight Tuesday. The dewpoint at 850mb will reach 11 degrees Celsius, which is very high for this time of year. This lines up with the passage of the storms as the dewpoint reaches 60 degrees F at the surface at 18Z Wednesday. Thunderstorms are expected and have a chance to be severe Wednesday. CAPE values do not become impressive at the surface as they do not go over 100. The LI is 0 which is not impressive but it is good for February. However, the omega values on the GFS are very high which will help with severe weather formation. Also, the LCL and LFC are very low and close together. Overall, thunderstorms are expected with a chance of them being severe. After the cold front passes, CAA will take over for the rest of the week and high pressure at the surface will dominate.

The cut-off low currently over Mexico will be the main weather maker for this week. This along with the unseasonably high temperatures will bring the area thunderstorms with a chance of severe thunderstorms. 0.75-1" of rain is expected to fall over mid-Missouri. The rain will mainly be from 18Z to 21Z Wednesday. Also, the rain is expected to be very heavy.

-Meier