Current Conditions at Sanborn Field
Monday Night: Cloudy. Widespread showers and isolated storms. Low of 59.
Tuesday: Becoming partly cloudy. Lingering showers in the morning. High 72.
Tuesday Night: Clear. Low 50
Wednesday: Clear. High 70.
Discussion: Temperatures have been well above the average the past two days, an approaching cold front from the northwest will bring widespread showers and scattered storms into Central Missouri Monday night. Storms will begin after 7 PM, and make their way southeast heading into the early morning hours Tuesday. The main threats with these storms and showers will be brief downpours and strong winds. Storms will begin to lose energy heading into Tuesday morning where they become showers. Rainfall totals remain below 0.5" with some isolated areas at 0.5". By noon on Tuesday, showers and storms will pass to the southeast leaving behind partly cloudy skies. Tuesday afternoon's high peaks out at 72 degrees. The overnight low for Tuesday night falls into the lower '50s with skies becoming clear. Wednesday, Central Missouri will continue to see clear skies with highs in the lower '70s. By Wednesday night, winds continue to flow from the northwest causing cooler overnight lows into the upper mid to upper '50s.
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Forecasters: Alexander, Gromada, Gotsch
Date Issued: 09/20/21 5:50 PM CST
Technical discussion:
This forecast was generated with the use of the 12z GFS.The main concern for this forecast period was the approaching upper level longwave trough approaching from the Great Plains causing overnight showers and storms Monday night into Tuesday morning. The GFS was used due to its accurate handling of the current upper air atmospheric conditions . The GFS was used in conjunction with the GFS Plumes.
Currently,a deepening positively tilted trough exists just west of the CWA extending from northern Minnesota,southwest towards southeastern Kansas. Out ahead of this trough, winds at the 850 mb level currently flow out of the south leading to above average temperatures for mid-September cresting into the lower '90s. Current analysis of approaching long wave trough suggest a change in future conditions Monday night.
Increased moisture at the 850 and 700 mb levels at 0z paired with increased CAPE values suggests the possibility of overnight storms out ahead of the approaching cold front. CAPE values are predicted to be in the upper 800's with wind shear near 25kts. These ingredients suggest storms beginning in Central Missouri after 7 PM. The main threat for these storms will be strong winds and brief downpours . Storms will continue to push southeast throughout the duration of the night weakening as the cold front surpasses ahead to the southeast. Showers will push east of the CWA Tuesday at 17z leaving behind lingering cloud cover. Expected rainfall amounts will fall below 0.5" with isolated areas reaching 0.5".
Tuesday afternoon, partly cloudy skies will begin to clear as winds shift out of the northwest. These northwesterly flowing winds at the upper-level will leading to below average temperatures Tuesday afternoon allowing for the high to top out in the lower '70s.
Central Missouri will continue to see northwesterly flowing upper level winds as a ridge sets up over much of the Great plains region. The overnight low Tuesday falls into the mid-to-upper '40s thanks to clear sky conditions and northwesterly flowing winds.
Wednesday and Wednesday night's main influence will be the approaching upper-level ridge. A substantial pressure gradient overhead Wednesday afternoon will lead to breezy conditions with sustained winds at 10-15 mph and gust up to 20 mph. Sky conditions will remain clear with a high topping out at 70.
The main concern for the next forecasters will be a developing long wave trough off of the western coast expected to head east by the end of the week.
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