Issued: 8pm on Sunday, September 21st 2025
Technical Forecast Discussion
Short-Term Forecast (Sunday 09/21/2025 through Tuesday 09/23/2025)
A trough aloft will begin to build throughout the short-term alongside a large line of surface fronts, placing Ohio upstream of this developing trough. Throughout the coming days, multiple low-pressure systems interconnected by frontal boundaries will slowly make their way southeast over Ohio, bringing us the possibility of showers and storms during this time. Some minor embedded shortwaves at 500 mb could pass near southeastern Ohio Tuesday morning and throughout the daytime Tuesday. Warm air will be present at 925 and 850 mb with much cooler air above it at 700 mb, providing plenty of instability for convective cells to develop. Though, some ever-so-slightly warmer air could sit just above at 500 mb, dampening any rapid convection aloft. During this time, the atmosphere will have plenty of moisture to further develop any convective storms, especially near the surface. At 500 and 700 mb, while abundant moisture will be present, most of it will be primarily in patches rather than being widespread like near the surface. Much of the mid-levels and aloft will have these patches of drier air, which could enhance storm development during the next couple of days. Although severe weather is not expected during these days, some short-lived storms could be a possibility throughout Monday and Tuesday.
Long-Term Forecast (Wednesday 09/25/2025 through Saturday 09/37/2025)
During the long-term, the trough aloft will deepen and become a large cut-off low at 500 mb. Ohio will continue to remain upstream of this trough, amplifying much of the unsettled weather we could experience during this time. While it’s uncertain exactly what will become of this trough, it may fully pinch-off looking past this forecast. At 200 mb, the trough will remain fairly cut-off, placing the state in a jet streak during the latter part of the week. Instability in the lower atmosphere may slightly weaken as the near surface levels cool minorly but could likely still be strong enough for convection to occur. Lapse rates will be fairly weak during the mid-to-late week, generally being around 5-6 C/km, but mid-level relative vorticity values may provide enough energy for storms to be relatively long-lived. Vertical velocity values throughout the mid-levels will be respectfully strong Wednesday and Thursday, indicating potential vertical motion during these days. Much like the short-term, we may see plenty of moisture near the surface at 925 and 850 mb and some decent amount of moisture through 200 mb, but there may be points of dry air aloft Wednesday and Thursday that may help destabilize the atmosphere further. By Friday and Saturday, while a cold front is expected to pass over on Friday, the atmosphere might slightly stabilize, and our rain chances are likely to decrease once again by then.
