Issued: 3pm on Wednesday, August 12th 2020
Technical Forecast Discussion
Short Term (Wednesday 8-12-2020 through Saturday 8-15-2020)
Fairly neutral vorticity advection will keep heights relatively the same over the next 12-24 hours. A speed max to our north is driving a surface anticycone at its right exit, making for fairly calm and pleasant weather over the general forecast area. Given some areas are just on the edge of this high’s influence, and a weak frontal boundary mainly along US-50, isolated afternoon convection may pop up (mainly to our south and east), due to sufficient CAPE in areas with slightly negative omega. Elsewhere, partly cloudy skies will remain prevalent throughout the day Wednesday with highs in the upper 80s. The previously mentioned stationary boundary will wobble back and fourth, following frontogenetic forcing. Off to the west, a region of strong positive vorticity will be advected eastward throughout the day Thursday into Friday. Weakly positive differential thickness advection should work to dig the height falls further south as this moves eastward, as well as slightly deepen these lower heights. This will create a split flow regime over the state, with the main jet ridging off to the north, and secondary troughing to the south. This in turn, should lift the stationary frontal boundary a tad north to line up along US -36 by Friday morning. This will increase convection chances throughout the forecast area Thursday, and greatly increase chances throughout the day Friday. No severe weather is expected at this time with this convection. Highs should consistently remain in the upper 80s with a few scattered lower 90s. Strongly positive differential thickness advection will work to rapidly deepen this trough by Saturday morning. This in turn will increase the height gradient south of the now closed upper level low located over central Ohio. This low’s strong VORT max, along with WAA will allow strongly negative omega to force rain and storms throughout the day Saturday. The previously mentioned speed max will rapidly generate a tight SFC cyclone near the Ohio River. This will further provide forcing for rain and storms on Saturday, along with fairly moderate winds. Because the forecast area will not be in the warm sector of this cyclone, no severe threat will be expected.
Long Term (Sunday 8-16-2020 through Tuesday 8-18-2020)
Saturday’s trough will eventually push eastward following PVA. Behind this, NVA is expected to briefly raise heights over the forecast area. This will make for a fairly dry Sunday outside of a few morning showers. Highs should cool into the lower 80s. After the brief period if height rises, PVA associated with a strong closed upper low in Canada will cause height falls throughout the state going into Monday night and Tuesday. Positive differential thickness advection will dig this trough southeastward, and tilt it more neutrally. The base of this neutrally tilted trough will locate itself over northern Ohio by Tuesday morning. Strong height gradients will drive a strong jet stream over this area. However, because Ohio will sit at the base of this trough (meaning strong and deep CAA), little weather is expected to come out of this other than a few showers/a rumble of thunder or two on Monday. Temperatures throughout this period should be well below normal.