Current Conditions at Sanborn Field

Thursday - Intermittent rain. High: 50-54

Thursday Night - Cloudy. Low: 44-48

 

Friday - Mostly Sunny. High: 70-74 

 

 

Friday Night - Clouds increasing through the night. Low: 48-52

Saturday - Steady showers throughout the morning and early afternoon. High: 56-60

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Discussion: 

For Thursday, expect widespread, spotty showers and cooler temperatures than we've previously experienced. Winds are out of the southwest but are light and accumulations of around 0.25 in are expected. Friday will be a pretty clear day as the previous system exits. However, by the evening, clouds will begin to increase as our next system enters the region, bringing strong rain for some of the late morning and early afternoon on Saturday. Accumulations are expected to be between 0.25 in and 0.5 in.

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Forecaster: Ede

Issued: 10:00 AM CST 08 April 2021

 

Technical Discussion (The nerdy stuff we are discussing in class):

The 06z GFS run for today was used as it resolved the split low over northwestern Missouri and southern Minnesota shown in the SPC surface analysis. Additionally, it was used to maintain continuity as the focus of this forecast is the aforementioned low pressure system to the north of Columbia. GEFS plumes were used for temperatures and rainfall totals.

Starting at 250 mb, the upper level low is situated over northwest Missouri, causing southerly upper-level flow for the region. This is associated with strong divergence at this level, as well, which is part of the reason why the region will be experiencing rain. As the forecast progresses into Friday, the upper level low moves to the northeast into eastern Iowa, causing the flow over Columbia to become zonal. By Friday night, the flow shifts again as a second upper level low develops over Nebraska. This will shift the flow from the west to the south southwest, bringing strong divergence aloft to Arkansas and southern Missouri. Moving into Saturday, the upper level low becomes enveloped into the larger flow and the winds over Missouri become more zonal and the divergence decreases.

Going down to 500 mb, the upper level low is stronger and further south than at 250 mb. The low is currently situated over the Kansas City, MO area and, as the day progresses, will move northeastward to the Quad Cities region of Iowa and Illinois by this evening. Strong circulations are associated with this low, which will increase the chances of rain for the Columbia area for today. By Friday morning, there is lingering circulation in northern Missouri, but largely zonal flow. However, by the evening, the flow shifts to come from the southwest as the upper level low over Nebraska strengthens, bringing an increase in the chances of rain. This upper level low is expected to sweep into mid-Missouri Saturday morning and be through by Saturday evening. Strong vorticity advection is expected in southern Missouri and Arkansas. By Sunday, Missouri is in northwesterly flow as the upper level low has moved into Indiana.

At 700 mb, the upper level low track is very similar to the track at 500 mb. The low is negatively tilted high in the atmosphere, but becomes more neutral as it moves towards the surface. With this low, there is a lot of moisture. By 15z today, central Missouri will see widespread rain as the atmosphere at 700 is nearly saturated. By the evening, the rain will dissipate as the moisture and the low move to the northeast. For Friday, much of central Missouri remains dry, but southern Missouri and Arkansas will see an increase in moisture in the afternoon as well as a large jump in vertical velocities, indicating the potential for convection. With large divergence at 250 mb, strong circulation at 500 mb, and strong vertical motions at 700 mb, the likelihood of strong to severe storms for southern Missouri and Arkansas is very high. As the secondary low from Nebraska moves into central Missouri Saturday, moisture and vertical motions increase, which will bring rain for Columbia on Saturday in the afternoon.

At 850 mb, the low affecting Missouri today stagnates over Iowa, which will contribute to the dissipation of the upper level low throughout today and into tomorrow. When this low is enveloped, the second system that affects Missouri comes in from Texas and Oklahoma. It joins with the upper level influence and quickly strengthens and brings strong southwesterly flow and moisture into Missouri. However, the low is not around for long as it quickly leaves Missouri by Saturday afternoon. Clouds will clear overnight and Sunday will likely dawn clear.

At the surface, the surface low is over southern Minnesota and will move further north as it dissipates throughout the day today. Missouri is experiencing strong warm air advection as this low moves to the north. Friday becomes quiet as the pressure gradient across Missouri decreases. Saturday, the low at the surface begins to influence Missouri, bringing more warm air advection across the region. After it moves through in the afternoon, cold air advection affects the region as winds are out of the northwest. As mentioned, Sunday will be a quiet day with light winds at the surface.

Rain totals for today are expected to be between 0.1 in to 0.25 in, with no severe storms expected. Rain totals on Saturday are likely to be between 0.25 in and 0.5 in. For Columbia, severe storms are not likely as CAPE values are very low throughout the forecast period. However, in southern Missouri, CAPE values exceed 2000 J/kg and the Bulk Richardson Number is 30 m^2/s^2, indicating moderate wind shear and the potential for supercellular development. This occurs Friday afternoon but dissipates by the evening.