In the short term, a warmup has begun but wintry weather could return due to a weakening polar vortex.

When the polar vortex is strong, cold air holds nearer to the Arctic Circle, explained AccuWeather meteorologist Paul Pastelok. “We are now seeing strong signals that the polar vortex may weaken to the point where one or more major southward discharges of cold air can occur in North America and Europe starting around the middle of March,” he said.

The impact locally appears uncertain. “The springtime also poses a challenge with cold air driven by polar vortex activity as you have the warming effects of the sun and shifting weather patterns to factor in,” Pastelok said.

The first day of spring is Thursday, March 20. The spring equinox — when the sun is directly above the equator — is marked for 4:01 a.m. Central time on that date.

KALLI PROUDFIT digs out a vehicle after Wednesday’s snow storm. (Theresa Proudfit photo)

NWS has a neutral outlook on spring temperatures in the U.P. after winter trended close to normal. February temperatures at the Iron Mountain-Kingsford Wastewater Treatment Plant averaged 15.8 degrees, which was 1.4 degrees below average. Temperatures in January averaged 14.2 degrees, which was normal, while December temperatures averaged 23.3 degrees, which was 2.4 degrees above the norm.

Water-equivalent precipitation was normal in

December but more than a half-inch below average in January and slightly below average in February. Snow depth at Iron Mountain-Kingsford plummeted to just 2 inches after a warmup late in the month.

About 10 inches of snow was measured in Aurora, Wis., during a storm period from Tuesday night into Wednesday night. There was heavier precipitation to the north, including an estimated 2 feet at Negaunee.

In February, the snowfall total at Iron Mountain-Kingsford was 12 inches. That compared with 31 inches at Ironwood, 22 inches at Baraga, 49 inches at Munising and 15 inches at Rapid River. The U.P. drought extends mainly through the counties bordering Wisconsin and lessens to abnormally dry conditions in the northern parts of those counties as well as all of Menominee County.

Observations at the Iron Mountain-Kingsford Wastewater Treatment Plant showed the highest temperature last month was 53 degrees on Feb. 24, while the lowest was minus 17 on Feb. 14.

Globally, the World Meteorological Organization reported that February was third-warmest on record after January was the hottest ever recorded. La Nina, the periodic cooling of ocean surface temperatures in the central and east-central equatorial Pacific, will likely end this spring, WMO said.

La Nina’s flipside — El Nino — played a role in 2024 being the warmest year on record globally. At Iron Mountain-Kingsford, temperatures in 2024 averaged 46.3 degrees, making it the second-warmest year on record, according to NWS data.

“The impacts of naturally occurring climate events such as La Nina and El Nino on climate patterns are taking place in the broader context of human-induced climate change, which is increasing global temperatures, exacerbating extreme weather and climate, and impacting seasonal rainfall and temperature patterns,” WMO said Thursday in a news release.