Pittsburgh residents might want to keep their umbrellas handy as showers and thunderstorms are forecasted to accompany the passing cold front today, which could also bring gusty winds and the off-chance of isolated severe storms, according to the National Weather Service in Pittsburgh. The good news is that, following the tempestuous weather, cooler and more comfortable conditions are expected to prevail over the weekend.
In the near term, two waves of precipitation are anticipated, one in the morning and another in the afternoon and evening, the marginal risk for damaging winds hinges on how much surface heating occurs before the latter wave and if the atmosphere can recover its surface-based instability after the morning showers, a complex interplay of elements that include cloud cover and the speed of the approaching front. The NWS Pittsburgh outlines that the primary factors influencing this recovery will be cloud cover and front speed/timing, and in scenarios where stronger storms develop along the frontal zone, the potential for damaging wind gusts exists, though a brief tornado can't be entirely dismissed, especially for regions south of the Mason-Dixon, where shear will be more oblique to the boundary.
As we march into the weekend, forecasts predict a initially dry Friday that will see a return to seasonable weather, with rain chances increasing in the evening - rain that is likely to continue on Saturday which could also see near-record low maximum temperatures, in fact the chill could bring about the coldest September 6th Pittsburgh has witnessed since 2011 as current modeling suggests a 10% probability of the high temperature tying the record low maximum of 60 degrees set in 1924, the NWS Pittsburgh cautions.
Looking ahead, the long-term outlook through the middle of next week is for dry, but cool weather to persist until a return to near-normal midweek temperatures, though a lake enhanced shower north of Pittsburgh come Sunday isn't off the table, as the ensemble models indicate the potential for such activity given the cold air aloft but, they might underscore it due to resolution limitations. This period will also see mostly VFR conditions except for the possibility of cloud-induced flight restrictions north of Pittsburgh as we head into Sunday and Monday.
The aviation sector will also take note of the weather changes, with this morning's areas of showers and potentially embedded thunderstorms creating patchy MVFR conditions, and the cold front crossing this afternoon and early evening likely leading to further MVFR/local IFR conditions and gusty winds. Following the frontal passage, IFR conditions are expected to develop mainly east of Pittsburgh overnight, with low clouds persisting into Friday morning, as reported by the NWS Pittsburgh Aviation Outlook.
