Current Conditions at Sanborn Field

 

Monday Night: Cloudy with light rain later. Low: 48

Tuesday: Cloudy with an afternoon and evening chance for thunderstorms. High: 79

Tuesday Night: Possible showers and thunderstorms in the evening. Low: 60

 

Wednesday: Showers and thunderstorms in the morning, some may be severe. High: 64

 

 

Wednesday Night: Showers in the evening, then clearing later. Low: 38

Thanks to IconArchive.com for the icons! 

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Discussion:

Be sure to keep your umbrella handy and your eye on the weather for the first part of this week! Showers and possibly severe thunderstorms are expected from Tuesday afternoon through Wednesday night. With these severe thunderstorms, there is a chance for heavy rain, strong winds, hail, and even possibly tornadoes. This weather will be brought by a low pressure system to our north and a cold front moving through Wednesday afternoon. Temperatures should remain a little warmer than last week until after the cold front passes through. Total precipitation are expected to be between 0.5" and 1" through Wednesday night. Remember to always be prepared for active weather, but especially the first half of this week!

-McMullen
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Forecasters: McMullen, Millsap

Date Issued: 04/11/2022 5:00PM CDT

Technical Discussion: 

 

The NAM was utilized for this forecast due to a better handling of surface temperatures as well as the low pressure system building up over the Rocky Mountains. Mid-Missouri is currently positioned to the north of a stationary front with a high pressure system centered over the Missouri-Iowa border keeping most of the showers and thunderstorms to the south. The main problem over the next couple of days will include a significant risk of thunderstorms Wednesday morning, with some perhaps being severe. Several severe weather parameters were examined during the making of this forecast in order to assess for related hazards.

A patch of upper divergence at 250 mb is currently making its way out of Missouri to the east, which has been partially responsible for the showers and thunderstorms in southeast Missouri on Monday. Similar updrafts will be passing to the south of the CWA on Tuesday evening at around 03Z, which may be too far south to have any significant effect on Mid-Missouri. A more remarkable area of divergence in the entrance region of an incoming jet streak will push through the CWA Wednesday morning. A trough positioned across the western CONUS will be negatively-titled, which is indicative of a strengthening meridional pattern. A 500 mb vort max will introduce large amounts of circulation into the region, which may help to encourage active weather.

The 700 mb map of relative humidity and vertical motion has indicated that the mid levels will remain dry until Wednesday when a string of moisture in the Lower Mississippi Valley becomes conjoined with an approaching LPS from the Middle Plains. Significant negative values of omega were also associated with these moisture packs, indicating upward vertical forcing. 850 mb winds will compose of southerly flow starting early Tuesday morning with the LLJ providing the lower levels over the Lower to Middle Mississippi Valley with a combination of moisture and warmer temperatures from the Gulf of Mexico. Surface winds will average about 15 to 20 kts on Tuesday and will maintain a southerly component. 1000-500 mb thickness and MSLP plots show tightly-packed solenoids along with southerly winds, advecting warmer air into the CWA and greatly increasing the temperatures on Tuesday. Surface winds will shift to the NW on Wednesday morning with the passage of a cold front.

As for the possibility of severe weather in the region, the NAM model soundings were examined to determine possible hazards. The soundings show the atmosphere briefly drying up Monday night until saturation coupled with a significant thermal inversion occurs underneath the boundary layer the following morning. By Tuesday afternoon, the profile becomes reminiscent of a loaded gun sounding with a well-mixed layer near the surface and a dry layer above a significant capping inversion at around 850 mb. Having raised several red flags, other factors such as vertical forcing and CAPE values were then considered. The greatest amount of forcing will likely take place around 15Z Wednesday as omega reached values well below -10 ubar/s, particularly around 700 mb. In terms of CAPE, all calculations between 18Z Tuesday and 12Z Wednesday were of at least 1000 J/kg with the greatest MU CAPE being measured in excess of 3000 J/kg at 21Z Tuesday. Future forecasters should maintain a watchful eye of the CAPE values and sounding plot. The wind profile had a tendency to veer with height, but did not show significant vertical shear until Wednesday at 15Z. Total Totals of 57 further suggests a potential for convective thunderstorms and a K Index of 31 suggests heavy rain for Wednesday morning.

Trace precipitation could be expected Tuesday night in amounts no greater than 0.05". As for Wednesday, precipitation could be expected accumulate between 0.5 and 0.8", which would result in a total QPF of 0.5 to 1" for Tuesday and Wednesday.

-Millsap