Issued: 3pm on Sunday, August 23rd 2020
Technical Forecast Discussion
Short Term (Sunday 8-23-2020 through Tuesday 8-25-2020)
Slight upper troughing due to PVA will continue to make its presence felt across much of the forecast area. Highs will remain quite moderate–in the lower and middle 80s for your Sunday. Due to PVA, as well as slight WAA at 500 mb, expect sufficiently negative omaga for convection to initiate along any convergence boundary. However, with low environmental shear, these cells will be slow movers (and non severe for that matter.) Watch for some isolated areas of localized flooding should you get under one of these cells. Omega will not be as strongly negative as yesterday, so convection and overall precipitation will not be as widespread. Over the next 24 hours, widespread NVA will occur, allowing heights to rise and therefore a ridge to build. Decreasing differential thickness advection will work together with this NVA to further amplify this ridge going into Monday. A broad anticyclone will develop at the right exit of a jet streak over Ontario and Quebec. Mainly calm weather will result from this, with slightly warmer than average temperatures (nearing 90 across SE Ohio) for your Monday. Positive vorticity generated by the lake breeze may stir up a few convective cells north of I-70, but elsewhere should remain dry. This calm weather will be short lived however. Monday night into Tuesday, A positive VORT axis willl advect into the area. This will drive sfc convergence and therefore a cod front. With a tight height gradient, a jet streak will dig off to the south along with an upper trough. This will be caused by strongly negative differential thickness advection between 700 and 500 mb. The previously mentioned cold front will be zonal in nature, moving from north to south across the state. The front should be across the I-76 corridor by noon Tuesday. With abundant MLCAPE nearing 2100 j/kg, and dry mid levels creating sufficient DCAPE around 800-900 j/kg, a damaging wind threat will be possible across the the eastern portion of the state (where the best sheared environment will be). With bulk shear values in the upper 20 kt area, multicells and possibly a few bowing linear storms will be the main storm mode. ML lapse rates near 6°C/km, and shear values only in the 20s kts will not be favorable for hail or tornado production across Ohio. SRH values less than 100 in both the mid levels and lower levels will also hinder hail growth and tornado production as well. A slight risk of severe weather has been issued for far eastern Ohio, with a marginal risk surrounding it. Be sure to stay alert and monitor your latest forecasts for Tuesday.
Long Term (Wednesday 8-26-2020 through Saturday 8-29-2020)
After FROPA Tuesday, highs across northern and eastern Ohio should briefly regress into the middle and upper 80s. Across the majority of the state, however, temperatures should reach the upper 80s and lower 90s for Wednesday. NVA will generate positive omega, keeping skies partly cloudy to mostly sunny throughout the day as well. The next weather maker should come Friday, in the form of the remnants of Hurricane Laura. Obviously, Ohio will not see any hurricane impacts. Its strong VORT max is expected to move across the southern tip of Ohio during the middle of the day, or perhaps the evening on Friday. There is disagreement on the track of this system. If Ohio ends up in the warm sector of the post-tropical system, a few isolated spin-ups will be possible across the state. If the track is further south, mainly heavy rain will be possible. The track and overall strength of the cyclone will depend on the degree of differential thickness advection, something guadance is having trouble on at the moment. Stay tuned for possible changes to the forecast. After this system pushes through, NVA will build a brief, slight ridge into the area. This will push highs into the upper 80s and lower 90s for Saturday, before the next weather maker comes in for the beginning of next week.