• Analyzing the impact climate pattern has on Pittsburgh's weather


    PITTSBURGH - You may remember January 2015, when Pittsburgh saw 8.5 inches of snow over three days, Jan. 25-27.

    It was one of the first bigger snows of the season. Flights were canceled because of the storm. There were also two decent snows the next month, on Feb. 14 and Feb. 21. Both brought 3.5 inches of snowfall.

    We all know Pittsburgh winters can be harsh. As Severe Weather Team 11 Meteorologist Danielle Dozier explains, climate pattern has a lot to do with that.

    You may have heard of El Nino and La Nina.  La Nina means water temperatures in the equatorial Pacific are rising and an El Nino is forecast to continue through winter.

    Typically, for the Pittsburgh area, a weak El Nino tends to bring average or slightly above-average snowfall. A strong El Nino brings warmer and drier-than-average conditions to the area.

    Average snowfall for the Steel City is a little more than 41 inches for the year. The last time there was an El Nino was 2015-16, and it was strong. Pittsburgh recorded below-average snowfall, with about 30 inches that year. Roughly 24 inches of that was seen in the months of December, January and February.  

    However, a weak El Nino in 2014-15 brought above-average snowfall, with 47.5 half inches.  

    Roughly 34 inches of that was recorded during the winter months.


    Some of our biggest snowfalls have occurred during years where there was neither an El Nino nor a La Nina, and our climate pattern was in what we call a “neutral phase.” Last season we were going from a la nina to a neutral phase and saw nearly 60 inches of snow!

    The largest snowfall on record for Pittsburgh happened during a neutral phase on Thanksgiving week of 1950. The city saw about 27 inches of snow.

    Other climate patterns, such as the Arctic oscillation and the North Atlantic oscillation, also lead to the variability of snowfall. Each can bring changes in the weather pattern across the U.S. When both are in the negative phase, it can lead to outbreaks of cold across our area which can set the stage for snow.

    At this time, a weak El Nino is forecast for this winter, which may bring a snowier season for Pittsburghers.



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