Friday Night: Increasing clouds, mostly cloudy by morning. A thunderstorm is possible (30%). Low: 72°
Saturday: Mostly cloudy. A few thunderstorms possible (60%). High: 80°
Saturday Night: Mostly cloudy. Thunderstorms (70%) Low: 69°
Sunday: Mostly cloudy. Numerous thunderstorms (80%) High: 77°
Sunday Night: Mostly cloudy. Scattered thunderstorms (70%) Low: 61°
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General Discussion:
Clouds will move in overnight, expect a Saturday morning round of thunderstorms to clip the University just to the south. Rain chances will continue through the weekend, however, thunderstorms are not expected during the football game Saturday. Overnight Saturday and especially Sunday morning, heavy thunderstorms are expected, and could bring the possibility of ponding on roads and flooding in prone areas. A final round of thunderstorms is possible (70%) Sunday evening, and is our best chance of a strong to severe storm (20%).
– Schwent, Yost
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Forecasters: -Slutter, Schwent, Yost
Date Issued: 09/12/2024 9:30 AM CDT
Technical Discussion:
Key Messages:
– Heavy rain accumulation (0.5″-1.0″) throughout this weekend could result in flooding for low lying and flood prone areas.
– A strong to severe thunderstorm is possible Sunday evening, with damaging winds being the most likely hazard.
– A cold front expected to traverse the area Sunday night will significantly reduce temperatures, with 70s expected during the beginning of the next work week.
Technical Discussion
The nose of the polar upper level jet stream is currently impinging upon our area, bringing along with it the start of a pattern change, as an upper level ridge in Texas gradually begins to decay. This will open the door for a trough currently located in southern California to move into the central United States over the weekend. This trough will bring low level moisture currently located over the four-corners region into our area. The trough will also prompt a mass response in the low levels and the surface, enhancing an already present surface cyclone, which is in the formative stages on the lee-side of the Rockies.
Overnight, as moisture continues to be advected into our area, cloud cover will increase substantially. At sunset, expect a few clouds in the sky, but by tomorrow morning, expect overcast will a few breaks in clouds throughout the day. This general pattern is expected to persist over the weekend.
A shortwave currently located in the OK/KS vicinity is riding anticyclonically around the previously mentioned ridge located in Texas. This will foster weak forcing for ascent across the region, resulting in disorganized thunderstorms Saturday morning. CAM guidance indicates that the most likely scenario with these storms is for them to move just south of us, however, given that Columbia is expected to be in the midst of a shortwave according to other deterministic guidance, the possibility of thunderstorms reaching the University is notable. As a result, a 30% chance of rain has been given for the overnight period, as the CAM solution of thunderstorms just missing is favored, albeit slightly.
The trough to our west will rapidly gain influence over our region, with robust large scale ascent present Sunday morning. This alongside HREF guidance indicating PWAT values of 1.8″-2.0″, and MLCAPE of 250-750 J/kg will result in numerous thunderstorms (80%), and the possibility of ponding on roads, and flooding in low lying areas. After this morning round of storms, it is unclear how the rest of the day will pan out. One potential solution, which is favored by the GFS, is that a front draped across our region will push southward earlier in the day, keeping us under elevated rain, resulting in a high temperature in the lower 70s. The other solution, favored by the NAM, is that this front will push north after the morning thunderstorms. This would result in substantially warmer temperatures throughout the day, in the upper 70s, and could perhaps foster some peeks of sunshine, destabilizing the atmosphere (MLCAPE 2000-2500 J/kg). Amidst deep layer shear of 45-50kts, this solution would also favor another round of organized thunderstorms in the evening hours, as the front crashes back south again, resulting in the possibility of heavy downpours, and perhaps a severe thunderstorm. The NAM solution is currently favored at this time, as the GFS has a notorious progressive bias, moving incoming air-masses into our region too quickly.
– Schwent, Yost