Residents of Pittsburgh should prepare for another warm and humid day ahead, with possible scattered afternoon and evening storms particularly south and east of the city. The National Weather Service in Pittsburgh reports that the unsettled conditions will persist through Saturday, ahead of a cold front.
A northwest flow aloft is expected today as warm temperatures continue to dominate the local climate. Despite the absence of significant shortwave passages, which will be deflected to the southwest, the presence of a surface boundary could lead to a slightly destabilized atmosphere, and with shear values of 20-30 knots, scattered showers and storms may ensue. According to the Weather Service, "Clouds and warm temperatures will be limiting factors," in the storm development.
Looking ahead to the short-term forecast, Friday is expected to experience similarly elevated temperatures as the ridge axis moves in. It won't be until the late afternoon when another shortwave trough potentially initiates further thunderstorms. As for Saturday, a stronger cold front is projected to usher in more widespread showers and storms, but there remains some uncertainty regarding the exact timing of its crossing.
By the end of the weekend, however, there appears to be a break in the muggy pattern of past days. "Dry weather looks to return for the end of the weekend and through the long term period," says the Weather Service. High pressure is set to build by Monday, bringing more seasonable conditions for the Labor Day celebrations and into the midweek.
Aviation forecasts indicate general VFR conditions for most airports, but early morning fog has affected FKL and DUJ with variable visibility. The Weather Service predicts this fog should lift to allow VFR conditions by mid-morning. A few afternoon thunderstorms are plausible across the area today, though the dry air aloft is expected to curb their spread. Going into the weekend, the approaching cold front presents the possibility of restrictions owing to scattered showers and thunderstorms, yet VFR should return as high pressure builds on Sunday and Monday.
