Issued: 8am on Thursday, May 15th 2025
Technical Forecast Discussion
Short-Term Forecast (Thursday 05/15/2025 through Saturday 05/17/2025):
A large shortwave trough will finally push out of the region later today as a prominent ridge begins to build. Behind this ridge is a potent cutoff low associated with an occluded surface low. Dry air will mix in and around this low-pressure system as relatively warmer, moist air mixes in with it. Cold air is expected to advect towards the Ohio Valley early Friday, and with the combination of dry air alongside it, we may not see many storms Thursday and Friday as a result. While this cutoff low will provide a mixed layer to promote cloud development and rising air, convective inhibition could impact whether or not these storms to cause severe damage. Looking into the late evening and early morning hours of Thursday into Friday, the greatest instability chance for southeastern Ohio will hit around 8 pm to 12 am. However, a temperature inversion at the surface with very minimal speed shear has the potential to inhibit any ingredients for severe storms and tornadoes. The positioning of a broad jet streak aloft will promote positive vortex advection (PVA) with diverging winds aloft. Storms will have the highest likelihood to form Friday evening into early Saturday with high directional wind shear but low speed shear, so any cells that may form aren’t likely to survive for long. Thankfully, by daytime Saturday, zonal flow aloft will allow more stable conditions to fill in and clear out any clouds by then.
Long-Term Forecast (Sunday 05/18/2025 through Wednesday 05/21/2025):
Looking towards the long-term, zonal flow in conjunction with high-pressure filling into the Ohio Valley will promote stable, clear skies. By Monday and Tuesday, a broad ridge will cover much of the eastern half of the CONUS, allowing warm, moist air from the Gulf to travel northward to the Ohio Valley. While unsettled weather isn’t expected these days, because of the transport of this warm, moist air, Monday and Tuesday are likely to be incredibly humid and muggy. By Wednesday, however, yet another low-pressure system developing from the Rockies will push through alongside a broad trough aloft. As of right now, it’s too early to tell if this will produce severe storms, but the possibility for rain still remains by Wednesday next week.
