Issued: 8pm on Sunday, August 18th 2024
Technical Forecast Discussion
Short-term Forecast (Sunday 08/18/2024 through Tuesday 08/21/2024):
Radar imagery current shows the persistence of isolated and scattered thunderstorms across much of Ohio following the southeasterly flow provided by an occluding low pressure system currently stationed near Lake Ontario. While still not significantly unstable, the region still displays CAPE values of ~1000 J/kg and moist lower-and mid-levels, allowing for these storms to continue to develop uninhibited, though as night approaches and the nocturnal inversion dominates, they will likely dissipate. This midlatitude cyclone will continue to be forced northeastward by a deepening and broad-spanning upper-level trough that will continue to persist over much of the eastern United States in the coming days. By Monday, as the trough plunges into the south, the advection of much cooler Canadian air will have begun, which will push daytime temperatures into the upper 70s. This advection will also channel in abnormally drier air, which will bring dewpoints down to 50°F by the end of Monday. Higher pressure will begin to develop from the left-entrance region of the upper-level Jetstreak further west, and eventually move eastward. This higher pressure isn’t significantly strong, but will still provide a stretch of calm and clear weather during this time. Similar conditions are to be expected Tuesday, though the advection of even drier air will bring dewpoints down to the low 40s by the end of Tuesday. By this point, the midlatitude cyclone will have been pushed off of the coast of New England, though another upper-level cut-off low will have developed and strengthened as it pushes southward.
Long-term Forecast (Wednesday 08/22/2024 through Saturday 08/25/2024):
This cut-off low will continue to strengthen and steer the trough eastward, pulling higher pressure of around 1022 mb into our area. Temperatures will still continue to be heavily influenced by the cooler, drier northern air, with a daytime high still around 78°F and dew points near 40°F, making for very stable conditions. By Thursday, the upper cut-off low will have pulled the trough to a point where flow begins to be cut off in the Deep South as it’s own independent shortwave, while the longwave begins to redevelop from the prominent ridge in the West, down through the Midwest, and out to the central East Coast. Because of this, advection of warmer air becomes more likely, especially given the strong blocking ridge shifting eastward. Daytime high temperatures in the low 80s are possible Thursday, transitioning to the upper 80s by Friday as the ridge becomes the dominant feature over the Midwest. With our region remaining downstream of the ridge, higher pressure near 1026 mb still remains prominent. This pattern continues by Saturday, where temperatures cross back over the 90 degree threshold once again as the ridge only continues to build northward, forcing warmer and somewhat more moist air into the area. Surface dewpoints around 60°F, and saturation in pockets near 700 mb and 600 mb will allow for the development of scattered low-level and mid-level clouds throughout the day, though precipitation remains unlikely.
