Current Conditions at Sanborn Field

          

Monday Night: Clear. Low: 30

Tuesday: Partly Cloudy. High: 56

 

Tuesday Night: Rain after 4 A.M. Low: 44

Wednesday: Showers with possible thunderstorms. High: 58

 

 

 

Wednesday Night: Rain with possible thunderstorms in the early evening. High: 51

 

 

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Discussion:

 Looks like father winter will be dropping in for another visit tonight! A freeze warning is currently in effect for central Missouri tonight and early Tuesday morning as temperatures are expected to dip below freezing. Gardeners should take precautions by covering their plants to prevent them from freezing over. Our next bout of rainy weather is expected to arrive late Tuesday night, which will persist through most of Wednesday night. There is a possibility of thunderstorms Wednesday evening with a slight chance of strong storms. Total rainfall amounts are estimated between 0.5" and 0.75". Temperatures are expected to steadily rise through the first half of the week with highs in the low 60s on Wednesday.

- Millsap

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Forecasters: McMullen, Millsap

Date Issued: 04/18/2022 5:00PM CDT

Technical Discussion:

The 12Z run of the NAM40 was chosen for this forecast from Monday night to Wednesday night. While the GFS had better surface temperatures, the NAM had a better handling on the placement of the pressure systems and locations of ridges and troughs across the CONUS.

The problem of the day for this forecast period is the chance for showers throughout almost the entire first half of this week. 

On the 250-mb plot of heights, winds, and divergence, Mid-Missouri is currently located in the exit region of a jet streak that is traversing southeast across Missouri. This region of the jet streak, in combination with a shortwave that passed through the Mississippi Valley 12Z Monday, brought some upper-level divergence resulting in some cloud cover on Monday morning. A ridge located over the western CONUS shifts eastward, bringing some divergence to Columbia seen at 22Z Tuesday. This ridge eventually passes to the east by 0Z Thursday, with another shortwave trough moving through Missouri at the end of the forecast period. 

Mid-Missouri is currently free of circulation at 500 mb, seen on the 500-mb plot of heights and vorticity. There is some vorticity to the north associated with an LPS over Wisconsin and the Great Lakes, but that stays north and east of Columbia. Vorticity from the previously mentioned ridge moves through 0Z Wednesday, but remains in southern Missouri. During the passage of this ridge, circulation stays spotty. After the a band of circulation migrates across the Upper Mississippi Valley at 0Z Thursday, circulation leaves Missouri for the rest of the forecast period.

The only moisture in the CONUS that can be seen on the 700-mb plot of heights and relative humidity is associated with the previously mentioned Great Lakes LPS on Monday. A large swathe of moisture from an LPS in Alberta stretches through the Mississippi Valley to central Texas flows through Mid-Missouri from 18Z Tuesday through 0Z Thursday.

Strong northerly winds on Monday, seen on the 850-mb plot of heights, winds, and temperatures contribute to the Freeze Warning that has been issued for Monday night. These winds will weaken and make a quick shift to the south about 20Z Tuesday with the passage of a small ridge through the Mississippi Valley. Eventually the winds will shift to the south/southwest and pick up speed about 0Z Wednesday. This pattern indicates the presence of a strong LLJ from 0Z Wednesday to about 6Z Tuesday, which also will contribute to the existence of the swathe of moisture seen at 700 mb. The winds will move to westerly flow about 6Z Thursday with the passage of the aforementioned Alberta LPS, now located in Ontario. 

On the plot of MSLP and 1000-500 mb thickness, CAA blankets the lower Midwest, indicated by strong solenoids. This movement of cold air also contributes to the previously mentioned freeze warning, which brings freezing temperatures and possibly frost. At 10Z Tuesday, a HPS crosses Missouri southeasterly, ending the CAA. From 0Z Wednesday to 0Z Thursday, WAA occurs with southeasterly winds. After 0Z Thursday, weak winds populate Missouri for the rest of the forecast period.

Soundings were used to analyze the timing of rain and the potential for severe storms from Monday night through Wednesday night. The soundings remain dry across the entire profile until the mid-levels become more saturated at 18Z Tuesday. While there is decent lift, CAPE is low, and other indices indicate showers, but likely not severe. Most of the profile becomes saturated at 09Z Wednesday. These parameters stay that way until 15Z Wednesday, when CAPE begins to pick up and remains above 600 J/kg until 03Z Thursday. Total totals also remain above 50 and LI stays below -3. After this, around 6Z Thursday, the sounding dries out. After analyzing these soundings, the highest chance for thunderstorms through Wednesday night seems to be Wednesday and Wednesday evening, however it is not very likely right now. QPF values are expected to be between 0.5" and 0.75" through Wednesday night.

Future forecasters should look to the potential for severe weather later in the week in addition to any changes with the potential for severe weather for the first half of the week. 

-McMullen