After a few scattered showers and storms Friday evening, conditions begin dry with mostly cloudy skies across Western Pennsylvania and Northern West Virginia. 

A thunderstorm complex moving around the periphery of our developing heat ridge will likely bypass us to the northeast today, with a low chance of a shower or storm northeast of Pittsburgh up to the I-80 corridor. The rest of our area should see mostly cloudy skies this morning with decreasing clouds and temperatures heating up by late afternoon with highs in the upper 80s. 

Our first bout of excessive heat of the summer builds in starting Sunday as a strong ridge of high pressure aloft in the atmosphere, a.k.a. a "heat dome," shifts from the Central US to the Eastern US. 

Current Conditions | School Closings & Delays | Submit Your Weather Photos

Humidity levels will start to increase Saturday afternoon, but will become most noticeable on Sunday. Sunday will likely feature our first 90-degree day of the year, with plenty of opportunities into next week as well. Most models agree that the core of the heat dome will peak in intensity and park directly over the Ohio Valley and Mid-Atlantic states Monday and Tuesday next week. 

The saving grace for the Pittsburgh metro is that our soils are very moist, and the evaporation of this moisture should keep afternoon air temperatures in check, mostly reaching the low to mid-90s. Despite this, it will be VERY humid, and this will lead to heat indices around 100 degrees and hotter from Monday through Wednesday during the afternoon.

As far as records go, the days Pittsburgh will be closest to record highs will be Monday (95F set in 1894) and Tuesday (96F set in 1882). DuBois and Morgantown, West Virginia, which are other sites in our coverage area that keep long-term climate records, may also break record highs during the Monday to Wednesday stretch. 

While we may stay just shy of record highs, record warm low temperatures are very likely to be met in Pittsburgh, along with Morgantown and DuBois. Air temperatures will struggle to drop below 70°F at night, which makes this heat very dangerous for those who don't have air conditioning. Extreme heat is the leading killer of all weather-related hazards, so individuals should take precautions in this upcoming stretch. 

As far as rain chances go for this week, we may see a stray shower or storm pop up in the heat of the day on Tuesday because of how hot temperatures will be near the ground. Slightly better chances of showers and storms look plausible on Wednesday and Thursday as the core of the heat ridge breaks down and a weak front moves into the area. 

This front does not look as potent as in earlier model runs, so it is possible the stretch of 90-degree weather may continue all the way through the end of the week.

Stay up to date with the KDKA Mobile App – which you can download here!