Severe storms could bring gusty winds and hail to Pittsburgh area before another round arrives overnight
We're entering a six-day stretch with a persistent and very active weather pattern across western Pennsylvania and much of the United States.
A deep trough associated with a colder-than-normal air mass across the West and a ridge associated with a warmer-than-normal air mass across the Southeast will lead to a very strong and persistent jet stream in between these two features that will send storm after storm system to our region.
Wednesday afternoon and Thursday morning are First Alert Weather Days because of the isolated severe storm threat. Saturday and Sunday could be First Alert Weather Days because of severe storms, heavy rain and possible flooding.
Main threats include gusty winds and small hail
The first wave embedded in the flow arrives by early to mid-afternoon with a chance of storms, mainly from Pittsburgh and points north. Timing looks to be between 12 p.m. to 5 p.m. Gusty winds and small hail could occur with some of the strongest cells.
A warm front will pass through after these storms, so temperatures will steadily increase into the evening hours with upper 60s over our southernmost counties, low to mid 60s in Pittsburgh and 50s generally north of the city.
These showers and storms will diminish in coverage with isolated cells possible through the late evening hours.
More storms expected overnight
A larger complex of storms will move east from Ohio late Wednesday night and into the predawn hours of Thursday. Strong wind gusts will occur along the leading edge of storms along with heavy rain. The time of arrival for this next round will be between 2 to 6 a.m. Thursday.
Lingering showers and storms are expected through the day Thursday, especially south and east of Pittsburgh. Another wave of widespread rain is expected Thursday evening into the overnight hours.
Friday morning will start with some widespread rain, but high pressure will nudge in from the north, leading to a few dry hours with lower rain coverage. This will be brief, however, as we watch another very strong disturbance and its associated low pressure lift northeast toward the Great Lakes. This will reinvigorate rain and thunderstorm chances for Friday night, Saturday, Saturday night and Sunday.
It is possible that we get back into the moist and unstable air on Saturday, which could revamp our severe weather threat. Multiple rounds of rain moving over the same locations could lead to a low-end flash flood threat.
How much rain will Pittsburgh get?
Total rainfall amounts through the next seven days will be upwards of 3 to 4 inches, especially from Pittsburgh and points north and west. Locally, higher amounts of rain are possible. The greatest threat for river flooding will be to our southwest but some flooding could occur locally as well.
A colder air mass will build in toward the early-middle part of next week with rain and snow possible by next Tuesday.