Harrisburg, Pennsylvania – A milder air mass pushing into the Mid-Atlantic ahead of St. Patrick’s Day will steer much of Pennsylvania toward rain during daylight hours, but nighttime cooling could still flip precipitation to wet snow between March 11 and March 17.
According to the National Weather Service Climate Prediction Center, Pennsylvania remains within a 40-50% probability zone for above-normal precipitation during the 8-14 day period. Temperatures are projected to trend near to slightly above seasonal averages statewide. That warmer pattern favors daytime rainfall for most lower elevations, though marginal overnight readings may still allow rain-to-snow transitions, particularly inland and across higher terrain.
In Harrisburg and along the Interstate 81 corridor, daytime highs in the 40s could keep most precipitation liquid. However, if steadier precipitation lingers after sunset and temperatures dip into the lower 30s, wet snow could briefly accumulate on grassy surfaces and untreated secondary roads. Across western Pennsylvania, including Pittsburgh and areas along Interstate 79, slightly cooler surface temperatures may support more consistent nighttime snow during pre-dawn hours.
Higher elevations in the Laurel Highlands and across northern counties near Interstate 80 remain more likely to see accumulating snow with each passing system. Heavier bursts may briefly reduce visibility statewide.
Drivers across Pennsylvania should monitor overnight and early morning road conditions where temperatures hover near freezing. Even brief wet snow can create slick spots on bridges and elevated highways. Additional updates are expected as the March 11-17 window approaches and system timing becomes clearer.
