Current Conditions at Sanborn Field

 

 

 

 

Wednesday: Rain with possible thunderstorms. High: 67

 

Wednesday Night : Clouds clear out overnight. Low: 38

 

 

 

 

Thursday: Mostly sunny. High: 43

 

Thursday Night: Decreasing clouds. Low: 21

 


Friday: Mostly sunny. High: 40

 

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Discussion: A low pressure system is moving its way through mid-Missouri on Wednesday. Attached to this low, a warm front is pushing north through Missouri Wednesday morning, warming our area to well-above normal and bringing in a lot of moisture from the south. Expect rainfall throughout the morning and into the early afternoon hours.

-Ritsema

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Forecasters: Ritsema, Clark, Cochran

Date Issued: 2/22/2023 10:00 AM CST

Technical Discussion:

The GFS model was prioritized in this forecast as the timing of the cold front and location of the low-track lined up well with observational data. The NBM was also utilized when forecasting temperatures and QPF. 

Topic of the day:

A low-pressure system is making its way through the Midwest this week tracking through Missouri into the western Great Lakes region. Widespread rainfall and thunderstorms will be occurring throughout Missouri with expected accumulations up to an inch in isolated locations. There's a possiblity that mid-Missouri will get dry slotted Wednesday afternoon, which could lower QPF significantly.

Synoptic overview: 

At the 300mb level, there is a trough over the western United States. This trough couples with the sub-tropical jet stream in the central United States, specifically over Missouri. When this trough begins to make its way over Missouri, divergence aloft is present Wednesday between 15-21z. On Thursday, at 03z, the jet stream begins to transition into zonal flow for the rest of the week.

The two jet streams begin to couple during the day on Wednesday. Due to this, shortwaves form over Missouri bringing a lot of vorticity to the region. This vorticity is present 12z Wednesday to Thursday 00z which is great forcing for the Wednesday thunderstorms. After frontal passage, no vorticity is present the rest of the week, as it moves out skies begin to clear up into Thursday.

Moisture is present Wednesday 06z to Thursday 00z, with full saturation between 15z and 21z. Mid-Missouri may get dry slotted Wednesday afternoon and if this happens QPF will be much lower than forecasted. Warm air advection occurs throughout the day Wednesday, then transitions into cold air advection after the cold front passage. Winds are from the west southwest throughout the forecast period. A line of raised vertical velocities along this cold front will only aid in the rainfall occurring midday. 

A strong low-level jet, up to 65 kts, is situated over the deep south into the lower-Midwest bringing warm moist air into Missouri. This LLJ hangs around until Thursday 21z when the low pressure system moves out of the area. The most moisture is present between the hours of 15z-21z on Wednesday with dewpoint temperatures reaching 10C.

At the surface, saturation is present Wednesday from 09z to 21z. The low tracks from southwestern Missouri to northeast Missouri and into central Illinois. Winds shifts to the northwest suggests the surface cold front passage occurs at 03z Thursday. After passage, a gradual temperature drop off is expected in the CWA.

Examining soundings shows elevated CAPE, 400-800 J/kg, between the hours of 06z-18z on Wednesday, leading to possible thunderstorms. Saturation exists at all levels until 18-21z with pwat values greater than an inch until 21z. Soundings also suggest the possible build-up of clouds in the mid-levels Friday afternoon.