Polar Vortex Is Strengthening: What It Means For PA Winter Temps, Snow

The forecast for warm temperatures on Christmas Day in Pennsylvania is a harbinger of what’s to come for most of the country through March, according to a new winter forecast.

Highs are likely to touch the 50s in the Philadelphia area, with clouds and a chance of rain, according to the National Weather Service. Out west in Pittsburgh, meanwhile, the highs will be in the upper 50s with rain likely.

Warm and wet weather is likely to be the theme for the region heading into the early part of 2026 for much of the south and the east, as the stratospheric polar vortex strengthens at the beginning of the year, according to the Weather Channel’s outlook.

Bizarrely, the more a stronger a polar vortex is, the less impactful it is, the Weather Channel says. A stratospheric polar vortex, which is higher up in the atmosphere and usually stable, differs from the better-known tropospheric polar vortex, which is lower down in the atmosphere and typically brings severe cold snaps to mid-latitude states.

It comes after several weeks of weather that has been at times frigid in eastern Pennsylvania, as well as a significant snow storm last week that left more than six inches of accumulation in many parts of the region. The likelihood of more events like that this winter appears somewhat diminished now.

The outlet's January to March outlook for Pennsylvania calls for:

• January: above average temperatures
• February: well above average temperatures
• March: about average temperatures, slightly warmer than normal

That falls roughly in line with NOAA's forecast for most of eastern Pennsylvania, which calls for warmer than normal temperatures with about an average chance of precipitation.

Highlights of the Weather Channel’s outlook include:

• January will likely continue the late-December pattern with above-average warmth across the southern two-thirds of the country.
• February could see the warmest weather relative to average along the East Coast.
• Without the polar vortex in play, conditions are expected to resemble La Niña: warmer than average in the south and cooler in the north.
• The northern U.S. will likely see wetter-than-average conditions, while the southern U.S. is more likely to be drier.

The ongoing flip to cooler, wetter weather in the North and Northwest is also likely to continue, the forecast said. Bouts of wetter, colder weather in other parts of the country aren’t out of the question.