Current Conditions at Sanborn Field
Tuesday: Clouds begin to move in. High: 56
Tuesday Night: Cloudy. Showers begin to move in later in the night. Low: 44
Wednesday: Overcast. Showers with a few possible rumbles of thunder. High: 60
Wednesday Night: Cloudy. Storms ending. Low: 51
Thursday: Partly Cloudy. Storms pick back up in the evening. High: 72
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Discussion:
April showers bring May flowers, and we're certainly seeing those showers this week! Although Missouri is under some high pressure right now, keeping out skies clear, showers begin to etch their way in tonight and continue through Wednesday evening. Total precip amounts will range around .5" to .75". The biggest chance for severe storms falls on Wednesday evening, but it seems that storms will remain fairly calm as they move through Columbia. Temperatures will finally begin to rise back up to average for this time of year, with Wednesday having highs in the lower 60s, and then finishing out this week in the mid to upper 70s.-Cade
GFS plots of 250-hPa height and wind show the amplified ridge/trough pattern over the CONUS transitioning to a more zonal regime near the end of the week as the LW trough to the east continues to move further in that direction. Prior to that, brief upper-level ridging will ensue Tuesday afternoon into early Wednesday morning. At this time, a shortwave will move off of the Rocky Mountains and bring mid-Missouri’s first shot of active weather. With it, however, Missouri will predominately be in the right exit region a jet streak to the west, so large-scale dynamic support will be somewhat limited at first. By the end of the forecast period, the polar jet stream will have begun its long-awaited retreat north helping to lock the cP and cA air masses up in Canada where they belong.
Regarding upper-level flow, much is the same story at 500 hPa. 500-hPa absolute vorticity shows increased (albeit relatively weak looking) circulation propagating into Missouri from the southwest by early Wednesday morning. These vorticity maxima will influence the forecast area into Wednesday evening. By Wednesday night and into Thursday is when the upper-level flow regime flattens to zonal likely keeping Thursday quieter. Outside the scope of our forecast period, Friday a longwave trough begins to dominate the western half of the CONUS and will provide the large-scale set up for an active weekend.
700-hPa plots of RH and vertical motion show deep-layer saturation over the mid-Mississippi Valley early Wednesday morning and sticking around into Wednesday afternoon. This moisture quickly pushes off to the east by Wednesday night but is replaced by a northward surge of saturation moving up from the south. This being much less widespread and a lack of forcing discussed above leads to thinking that rain chances for Thursday are less. Moisture transport at 850 hPa looks most efficient Wednesday morning with a 50-kt LLJ setting up over Missouri. 850-hPa moisture transport vectors (MTVs) and dewpoint show moisture convergence in Missouri on Wednesday being pushed out by a weak boundary by Wednesday evening. This boundary will stall keeping the moist airmass to the south on Thursday. Similarly, MSLP and surface winds show a weak cold front that will move through Wednesday afternoon and stall. This will eventually lift back north as a warm front overnight Thursday into Friday.
GFS soundings support much of what was said above. The column will gradually saturate from the top down Tuesday night into early Wednesday morning. Rain looks to begin between 09z and 12z Wednesday. Soundings favor destabilization of the atmosphere as the day progresses. By Wednesday early afternoon, MUCAPE reaches near 1500 J/Kg. As such, some isolated thunderstorms embedded in the larger stratiform rain looks likely. Upon passage of the aforementioned cold front, the column dries rapidly as rain looks to taper off after sundown Wednesday evening. Thursday will likely see some sunshine to start the day allowing for temperatures to warm considerably from the early week. The wind profile on the sounding shows the lifting of the warm front nicely. Chances for thunderstorms increases again, Thursday afternoon/evening as the atmosphere will destabilize by the afternoon with now surface based CAPE reaching near 1000 J/kg. This, combined with a strongly veered wind profile may result in some stronger storms. While severe storms shouldn’t be ruled out, lackluster low-level lapse rates should prevent a widespread severe event. Showers and thunderstorms will continue into Friday morning.
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Forecasters: Cade, Travis
Date Issued: 04/19/2022 10:00AM CDT
Technical Discussion:
Prepare for a soggy few days ahead as chances of rain exist for the remainder of the week. The main focus of this forecast period is narrowing down the timing and amount of rain later this week. The 06z GFS was primarily used for this forecast due to its better handling of the ridge/trough pattern set up over the CONUS at initialization. Additionally, the GEFS ensemble had noticeably smaller spread in total QPF than the SREF ensemble.
GFS plots of 250-hPa height and wind show the amplified ridge/trough pattern over the CONUS transitioning to a more zonal regime near the end of the week as the LW trough to the east continues to move further in that direction. Prior to that, brief upper-level ridging will ensue Tuesday afternoon into early Wednesday morning. At this time, a shortwave will move off of the Rocky Mountains and bring mid-Missouri’s first shot of active weather. With it, however, Missouri will predominately be in the right exit region a jet streak to the west, so large-scale dynamic support will be somewhat limited at first. By the end of the forecast period, the polar jet stream will have begun its long-awaited retreat north helping to lock the cP and cA air masses up in Canada where they belong.
Regarding upper-level flow, much is the same story at 500 hPa. 500-hPa absolute vorticity shows increased (albeit relatively weak looking) circulation propagating into Missouri from the southwest by early Wednesday morning. These vorticity maxima will influence the forecast area into Wednesday evening. By Wednesday night and into Thursday is when the upper-level flow regime flattens to zonal likely keeping Thursday quieter. Outside the scope of our forecast period, Friday a longwave trough begins to dominate the western half of the CONUS and will provide the large-scale set up for an active weekend.
700-hPa plots of RH and vertical motion show deep-layer saturation over the mid-Mississippi Valley early Wednesday morning and sticking around into Wednesday afternoon. This moisture quickly pushes off to the east by Wednesday night but is replaced by a northward surge of saturation moving up from the south. This being much less widespread and a lack of forcing discussed above leads to thinking that rain chances for Thursday are less. Moisture transport at 850 hPa looks most efficient Wednesday morning with a 50-kt LLJ setting up over Missouri. 850-hPa moisture transport vectors (MTVs) and dewpoint show moisture convergence in Missouri on Wednesday being pushed out by a weak boundary by Wednesday evening. This boundary will stall keeping the moist airmass to the south on Thursday. Similarly, MSLP and surface winds show a weak cold front that will move through Wednesday afternoon and stall. This will eventually lift back north as a warm front overnight Thursday into Friday.
GFS soundings support much of what was said above. The column will gradually saturate from the top down Tuesday night into early Wednesday morning. Rain looks to begin between 09z and 12z Wednesday. Soundings favor destabilization of the atmosphere as the day progresses. By Wednesday early afternoon, MUCAPE reaches near 1500 J/Kg. As such, some isolated thunderstorms embedded in the larger stratiform rain looks likely. Upon passage of the aforementioned cold front, the column dries rapidly as rain looks to taper off after sundown Wednesday evening. Thursday will likely see some sunshine to start the day allowing for temperatures to warm considerably from the early week. The wind profile on the sounding shows the lifting of the warm front nicely. Chances for thunderstorms increases again, Thursday afternoon/evening as the atmosphere will destabilize by the afternoon with now surface based CAPE reaching near 1000 J/kg. This, combined with a strongly veered wind profile may result in some stronger storms. While severe storms shouldn’t be ruled out, lackluster low-level lapse rates should prevent a widespread severe event. Showers and thunderstorms will continue into Friday morning.
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