When trying to predict winter weather across the country, the biggest thing you have to think of is La Nina. La Nina is a common weather experience where the ocean water temperature in the Pacific Ocean is 0.9 degrees Fahrenheit below normal. Keep in mind, these occurrences can extend for even years at a time.

This fall, we are transitioning into a weak La Nina.

What a typical La Nina does over the winter is send a jet stream into the Northwest, dipping further south across the Plains/Midwest, and curving upward around the Mid-Atlantic/Northeast. Areas above this are likely to experience colder temperatures and above-normal precipitation, while below the line shows warmer, drier forecasts. 

Just as often, an occurrence called El Niño occurs, where the Pacific water is warmer than normal, affecting winters in the opposite way.

Official Outlook

This winter will rely much on where in Pennsylvania you are.

The La Nina jet stream will likely track a little more western than normal. As a result, it looks like there's a decent chance our winter could trend slightly milder than normal.

But - thankfully - that doesn't mean our snowfall totals will fall majorly behind.  Despite many calling for a ‘gentler’ winter, expect much above-normal precipitation, which will lead to more rain or snow than usual. Keep in mind that predictions from the Farmers Almanac have been lacking in accuracy, and to aim for more of a NOAA forecast for more likely predictions.

Pennsylvania looks like the more east you live, the milder you'll see. Western PA should look forward to much precipitation.  Temperatures might jump from barely midler out near Pittsburgh and Erie to moderately milder near Philadelphia.  Areas nearing Erie should expect the most precipitation, Pittsburgh should expect the coldest temperatures of the state (not colder than average, however), and the southeast portions should brace for likely the warmest temperatures in the state.

Comparing Outlook Sources

For NOAA’s forecasts, they are calling for very mild conditions in Eastern PA and slightly milder than average temperatures further west.  The Farmers Almanac calls for a cold winter far west and milder elsewhere.  Old Farmers Almanac calls for cold temperatures further south, and milder for the North.

NOAA’s forecast calls for above-average precipitation throughout the state, especially in the northwest portions. Farmers Almanac calls for high precipitation amounts in all of the state.

Old Farmers Almanac predicts drier conditions for the state.

Sources: NOAA, Farmer’s Almanac, Old Farmer’s Almanac.