Current Conditions at Sanborn Field

Monday: Cloudy. High: 76

Monday Night: Rain. Low:52

 

Tuesday: Cloudy with rain. High: 65

 

Tuesday Night: Rain with possibility of Thunderstorms. Low: 42

 

Wednesday: Cloudy with rain. High: 50

Thanks to IconArchive.com for the icons! 

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

Discussion: 

Spring has sprung! Right now, mid-Missouri is currently under a Hazardous Weather Outlook for elevated fire danger today and the chance of thunderstorms tonight. The SPC has put mid-Missouri in a marginal risk of severe weather for tomorrow due to the possibility of hail, damaging winds, and the possibility of a tornado. Most of the severe weather will stay in the southern half of the United States, but continue to stay weather aware for Tuesday! A low pressure system originating in the southwestern region of the United States will make its way to the mid-Missouri region which will dominate our weather pattern for the first half of the week.  This will make for above average temperatures and a chance for precipitation for most of the first half of the week. Precipitation totals after this event will range from trace amounts to a quarter of an inch. Make sure to keep those umbrellas handy for this week!

 

- Gromada

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

Forecasters: Baker, Gromada, Bongard

Date Issued: 3/21/2022 10:00AM CDT

Technical Discussion: 

 

For this forecasting shift, the NAM was the model of choice due to the handling of temperatures and the low pressure system tracking northeast from the Four Corners area into the Central Plains Monday into Tuesday. The problem of the day consists of the low pressure system moving across the Central Plains begins to occlude as it parks itself over western Kansas. Thunderstorm possibility is light, as persistent rain will cover the CWA Monday night into Wednesday morning. Cooler conditions will be expected Wednesday as the occluding system parks itself over the Middle Mississippi Valley.

An elongated shortwave trough begins to deepen and push northeast Monday morning. Ahead of the system, strong southerly winds from the south reach up to 60 kts over mid-Missouri leading into Monday evening will bring deep low-level moisture to the area from the Gulf of Mexico.  This is evident on IR satellite imagery, as low level clouds begin to populate over the Southern Plains region.

As the system pushes northeast into the Central Plains, divergence values begin to increase as a jet streak is evident on the right side of the trough. This jet streak combined with the one situated over the Northern Ohio River Valley gives way to divergence aloft as the left entrance region, and right exit regions couple. As the jet streak on the right side of the trough approaches a ridge, it will lead to an imbalance of forces leading to increased divergence and vertical motion, evident on 250-mb Divergence values Tuesday at 10Z. The entrance region then will strengthen due to frontogenesis aloft. 

Along with the large values of divergence in the upper level, the 500-mb vorticity map shows a similar story. A band of lift and spin connected to the low pressure system over the Four Corners begins to weaken after making its progress across the Central Plains late Monday into Tuesday afternoon. As the system begins to occlude, the cold, upper level low parks itself over western Kansas. Values of lift and spin begin to move over mid- Missouri around 02Z Tuesday. It then cycles through the area with a few weaker values between 07Z and 09Z. Another shortwave rides along the upper level meridional flow as it moves south closer to mid-Missouri down from central Canada.  This strengthening system should be closely monitored by future forecasters.

As the system pushes northeastward throughout Monday afternoon into the evening, a LLJ sets up early Monday morning southerly winds across the southern Plains and Lower Mississippi Valley regions. 50-60kts LLJ will surge the area with warm temperatures and low level moisture, evident in low level clouds that will move in later Monday afternoon. These large values will help feed the low pressure system as it moves its way across the central Plains. Rain begins late evening Monday night, and will stick around through Wednesday morning.

With the help of the LLJ, cloud cover could impact the temperatures to be not as warm as yesterday, but the southerly wind will still keep it in the lower 70s. Tight solenoids are evident on the 500-1000mb Thickness map late evening Monday. WAA mixed with the strong LLJ will bring some instability to the area as the system approaches; however, CAPE values stay below 500 J kg^-1 so thunderstorms should not be likely, but with the large amount of lift shown at 03Z Tuesday, a few rumbles could be possible as seen on the sounding.

As the system begins to occlude over mid-Missouri, the cold air to the west of the cyclone advances rapidly southward around the center of the low pressure, cutting it off. With temperatures cooling down Wednesday due to the occlusion of the system, chances of mixed precipitation is low and the main form of precipitation will be rain for the remaining of the forecast period. Rain amounts will total to around 0.5-.99'' Monday night into Tuesday with trace amounts Tuesday afternoon into Wednesday.

 

-Baker