Current Conditions at Sanborn Field
Monday Night: Increasing clouds. Low: 46-50
Tuesday: Partly to mostly sunny. Breezy. High: 70-74.
Tuesday Night: Mostly cloudy. Low: 54-58.
Wednesday: Overcast with showers and thundershowers possible. High: 66-70.
Thursday: Cloudy with rain and a few thunderstorms. High: 62-66.
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Warm and dry conditions are creating high fire danger across mid-MO for Monday afternoon. Overnight, things will remain warm, as southerly winds and high clouds help to keep temperatures in the upper 40s. Tuesday looks to be the warmest day of the forecast, with highs in the lower to middle 70s. It will also be breezy on Tuesday, with winds gusting up to 30 mph. Fire danger concerns will be lower, however, with increasing humidity ahead of our next storm system. Clouds will then build back in Tuesday night into Wednesday, and an upper-level disturbance will provide our first chance for rain (and even a few thundershowers) Wednesday afternoon. Much better chances of rain will move in for Wednesday night into Thursday, with widespread soaking rain and thunderstorms likely ahead of a slow-moving cold front. Flooding may become a concern by late in the week as the front stalls just to our south and allows repeated rounds of rain in mid-MO.
*** A mild and spring-like pattern will continue for another couple days, before the pattern becomes much more wet and active late in the forecast period.***
RAP 48-hour analysis loops at 500-mb reveal a persistent ridging pattern across the central United States. This ridging has allowed for several days of mild and sunny weather, and a lack of low-level moisture has contributed to high fire danger both Sunday and Monday afternoon. Currently, WPC surface analysis reveals a large sfc high based over the southeastern CONUS. This puts mid-MO firmly in the WAA zone on the backside of the high, which is confirmed by the very warm (upper 60s to near 70) degree surface temperatures across much of the state. Dew points in the lower 30s and upper 20s, along with 10-20 kt wind gusts, are leading to ongoing fire weather concerns in and west of Columbia.
Overnight, look for the southwesterly flow to continue. This will prevent temperatures from plummeting despite very low dew points. The 18 UTC HRRR, 12 UTC GFS/GEFS, and the 15 UTC SREF all concur on lows overnight in the 46-50 degree range. Additionally, winds at ~700-mb to 500-mb will advect some high clouds into mid-MO.
For Tuesday, southwesterly flow and WAA will once again remain the dominant features in the pattern. Short-range hi-res models indicate clearing skies for the afternoon, with GEFS/HREF ensembles supporting this prognosis. Additionally, surface winds will likely be sustained at 10-20 kt out of the south, with gusts perhaps even higher than this. Assuming a period of sunny skies for even a few hours Tuesday afternoon, insolation and WAA will combine to lift temperatures into the low to mid 70s. Additionally, surface moisture currently present (as of ~20 UTC Monday) over southern TX will advect northward into mid-MO starting Tuesday afternoon, raising dew points significantly and putting an end to the majority of fire weather concerns.
Due to the higher dew points (SREF/GEFS put Td at COU between 50 and 55 F), lows Tuesday night into Wednesday will remain much warmer, with continued WAA and cloudier skies keeping lows in the middle to upper 50s - well above climatological normal highs for this time of year.
Wednesday into Thursday is when things will become much more active. The aforementioned WAA will continue in earnest throughout the day on Wednesday, increasing surface dew points steadily into the middle to upper 50s by afternoon. Additionally, a shortwave trof at 500-mb is progged to kick out into the Plains Wednesday morning, which will support a positively-tilted surface low. This low will likely take a track well north of mid-MO as it rides the boundary between warm, humid air to its south and colder air to its north. However, the lift provided by this disturbance may be sufficient to touch off some showers or even thunderstorms by Wednesday afternoon, with SREF mean MUCAPE in the 200-300 J/kg range.
The (first) main round of precipitation looks to hold off until Wednesday night into Thursday. The aforementioned surface low will skirt off to the northeast, leaving a slow-moving cold front in its wake to slowly drift down into mid-MO Wednesday night - Thursday. As it does so, southerly flow will persist along and ahead of it, with the 12 UTC GFS indicating a powerful 850-mb LLJ over mid-MO by Thursday morning. This would provide an excellent setup for the training of showers and thunderstorms during the day Thursday, given high PWATs (near to just above 1 inch) and elevated MUCAPE between 200 and 400 J/Kg. Severe weather currently looks unlikey, though it certainly cannot be ruled out given the strong dynamics present with this system. The main lacking ingredient will be healthy surface-based CAPE, although - if we can see clearing for a few hours before the front pushes through Thursday afternoon - it may be possible to have a few severe storms in mid-MO.
Right now, GEFS and SREF means through Thursday night indicate the potential for between 0.5 and 1 inch of rain, with a few of the outlier solutions predicting much more. The front that will pass through Thursday is then expected to stall south of Columbia, leaving mid-MO with the potential for several days of repeated heavy rain late in the week. Whereas we began the forecast period with fire danger concerns, we may well end it with flooding concerns, with the 12 UTC GEFS mean through next Monday at 3.43" of QPF.
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