Why it’s harder to warm up this year

In the middle of March 2012 we weren’t just thinking spring, many of us were thinking summer. Temps swelled to the 60s but that wasn’t enough so we rose to the 70s. A week later we set consecutive records for an all time March temperature with sizzling 83 and 84 degree days. This year we’d be ecstatic to hit the 40s, so what gives?

When it comes to March weather you have to keep one thing in mind, snow cover. Just days from the spring equinox our sunlight is just as strong as it is in late September. But sunlight needs something to warm up. In March of 2012 our last measurable snowfall occurred on the 4th. By the 7th our snow cover shrank to small pockets here and there. The next few days brought a mix of sun and clouds. With our frigid blanket melted off the ground, the warm March sun was easily absorbed into the thawing ground resulting in daytime highs that resembled a bull market.

Satellite photos of snow cover on March 13, 2012 vs. March 13, 2013. Credit: NASA

This time around the thaw has been meager at best. We’re still getting temps above freezing on most days but as of March 13th, our snow cover stands at a solid 3” in Milwaukee. With late winter snowfalls exceeding a foot in places such as Kenosha and Sheboygan, other areas may have even more snow on the ground. So on a sunny afternoon like the one we had Wednesday, temperatures respond as fast as a teenager told to clean his room. The sun simply reflects off the snow. To turn the tundra more temperate quickly we need one of two things: 1) A solid, all day rain with near normal temps to wash away the snow 2) a gusty south wind to bring in mild air from the snow free south. We saw the first option on March 10th which cut our snow cover by 5”. But it simply wasn’t enough to complete the job.

The days ahead feature neither option. Instead, we may add to our snow cover before dropping below freezing for all but a few hours this weekend. If it’s the milder side of spring you’re looking for you’ll just have to wait a while longer. Last year we enjoyed spring at the end of winter. This year reminds us we can still see winter at the start of spring.