Current Conditions at Sanborn Field

Friday Night - Clear skies. Low: 50-54

Saturday - Mostly sunny. High: 70-74

Saturday Night - Clear. Low: 54-58

Sunday - Partly cloudy. High: 70-74

Monday - Partly cloudy. High: 72-76 

 

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Discussion: 

Comfortable weather will continue here in mid-Missouri for the next couple of days due to a high pressure system over the eastern United States. Clockwise flow around the pressure system will keep winds out of the south going into the weekend. Friday's clear skies will continue overnight with temperatures in the low 50s. The high pressure to the east will park itself there for the remainder of the weekend keeping skies clear and temperatures above average into Saturday and Saturday night. Persistent winds from the south will bring added moisture from the Gulf which will lead to increasing clouds on Sunday. These clouds will stick around into Monday.

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Forecaster: Orr, Travis, Vochatzer

Issued:  5:30 PM CST 6 November 2020

 

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

Over this forecasting period, our region continues to see unseasonably warm temperatures and clear skies due to ridging to the east and a southerly winds. Due to good model consensus, this forecast was assembled using the 12z GFS, the 12z NAM, GEFS/SREF plumes, governed by persistence forecasting. 

The 12z GFS 250-mb plot of upper level winds and heights indicates the presence of ridging in the west over Kansas. This ridging moves into the Mid-Mississippi Valley on Friday and through Saturday. An upper-level, cut-off low over Louisiana, in combination with this ridge, blocks Gulf moisture from reaching Missouri, preventing the formation of any clouds or precipitation throughout the weekend. Beginning on Saturday at 18z, GFS 500-mb maps of heights and vorticity show circulation propagating into our area from the southern low. That being said, nothing will come of it due to little moisture in the atmosphere. The low begins to break down by 12z on Sunday, allowing the formation of clouds throughout Sunday and into Monday. 

GFS 700-mb plots of heights and relative humidity suggest that significant amounts of moisture will not reach our area until late Sunday night and into early Monday morning. This makes sense given that the moisture had been blocked by the Louisiana low, which will no longer be an issue by this time. Partly cloudy skies will persist from Sunday into Monday due to the increase in moisture at this level. The reason for Missouri's unseasonably warm temperatures becomes very apparent when looking at GFS 850-mb height and winds. Southerly to southwesterly flow persists throughout the entire forecasting period, keeping the temperatures warm. After the upper-level low begins to break down, winds at 850 mb will shift from southwesterly to more southerly with an origin from the Gulf.

The pattern described in the upper levels translates well to the surface level, with a high pressure system to the east of Missouri. Tropical storm Eta will remain to the south of Cuba until the end of the weekend. That system, working alongside the high pressure system over the Mid-Atlantic states keeps low-level/surface flow over the Gulf of Mexico westerly and zonal. As mentioned above, this will keep moisture locked up over the Gulf. As Eta gets closer to Florida, the zonal flow breaks down and moisture is able to reach Missouri. 

Monday's shift should watch a longwave trough digging into the western CONUS by Monday which will result in an active storm track next week.