As Pittsburghers enjoy a stretch of dry and warm conditions today, changes are on the horizon. The National Weather Service Pittsburgh, PA, forecasts an incoming wave of showers and possible strong thunderstorms starting late tonight through Sunday. According to their latest advisory, a cold front is approaching, and it is expected to stall over southern Pennsylvania, which could bring isolated showers to areas near PHD this afternoon. High temperatures will climb 5 degrees above the seasonal average.
The short-term outlook appears to be unsettled. A digging shortwave trough is progged to track from the Upper Midwest tonight, as surface low pressure develops in response across IL and IN, SE of the trough. This system will pull the cold front northward, transition it to a warm front, and bring shower chances north of PIT. There is potential for thunderstorms fueled by a low-level jet and minimally elevated instability across northwest PA through OH.
The cooldown will commence Sunday evening post-frontal passage, as the storm prediction center has placed southeastern areas of Pittsburgh within a Marginal Risk for severe storms. Moreover, Sunday could see winds gusting between 30-35mph, with a broken line of showers and embedded thunderstorms expected along the front. Greater wind shear and MU CAPE values hint at the potential for damaging winds, primarily southeast of Pittsburgh.
As we transition into next week, the unsettled weather is not relenting. Forecasts indicate that continued cold northwest flow from the Great Lakes and several shortwaves will maintain a scattered shower presence. The upper atmosphere's chill might even allow snowflakes to mix in across the higher elevations, where temperatures could drop to around -2 degrees Celsius at 850 MB. Winds are also expected to persist, ranging from 20-30mph.
The aviation forecast suggests VFR conditions throughout the day for those with skyward concerns, although high cloud cover will keep increasing. While rain chances remain meager this afternoon, probabilities shoot up after 06z tonight, especially along the I-80 corridor come Sunday morning. As we look further into next week, building high-pressure mid-week should return dry weather and low restriction chance into the weekend, according to the advisory for pilots and travelers.
