What has changed

No major changes to the upcoming forecast.

Messages

Showers and thunderstorms are expected across parts of Northeast Ohio and Northwest Pennsylvania this evening into early tonight. Locally heavy rainfall, gusty winds and small hail is possible this evening.

Cooler weather with occasional lake effect rain showers continue across parts of Northeast Ohio and Northwest Pennsylvania through early Tuesday.

Scattered showers and thunderstorms are possible Wednesday night into Thursday.

Discussion

KEY MESSAGE 1. An upper-level low remains situated over the Great Lakes region today with the occluded surface low right along the Ontario/Quebec border. A compact mid-level shortwave trough is working its way around western edge of the upper low and will approach the forecast from the north this evening. Paired with the left exit region of a jet streak over the western Great Lakes and we have solid forcing for ascent and pretty good confidence in timing and areal extent of precipitation this evening into early tonight.

We start with scattered showers and storms areawide this afternoon as MLCAPE exceeds 250 J/kg underneath the jet streak forcing. The impending shortwave will focus a better period of thunderstorm development roughly along and northeast of I-80 in Northeast Ohio and Northwest Pennsylvania between 7 PM and 12 AM. This is where MLCAPE will be greatest (>500 J/kg) and exists the chance for organized convection that will have the potential for lightning, gusty winds (most likely in the 40-50 mph range), small hail, and heavy rain.

While the mid-level speed max will be offset to the southwest, effective bulk shear of around 25-35 knots should be sufficient for an organized convection. Deep layer shear should be enough to produce strong winds but lack of DCAPE and waning low-level lapse rates is likely to make 40-50 mph gusts more common rather than 58+ mph (severe thunderstorm warning criteria). Small hail is likely to be pretty common in most thunderstorms this evening, aided by low freezing heights around 8-9kft and modest mid-level lapse rates. Large hail at or exceeding 1" is unlikely but possible with any rotating updrafts.

Heavy rain is likely with thunderstorms with minor flooding possible is low-lying or flood-prone areas. Precipitation is unlikely to reach amounts for flash flooding.

KEY MESSAGE 2.. Below normal temperatures continue through at least Tuesday with lake effect rain showers continuing tonight through Tuesday morning. Rain is likely to be more more persistent in Northwest Pennsylvania, compared to the "snowbelt" region of Northeast Ohio where rain showers will be more intermittent.

KEY MESSAGE 3. Temperatures and humidity build back to near normal Wednesday and Thursday ahead of our next upper-level trough and low pressure system. Scattered showers and thunderstorms are expected Wednesday night into Thursday with chance of rain peaking in the 40-60% range. Can't completely rule out severe weather, but at this point most storms look to remain sub-severe.