A big cold blast is on the way for Halloween. It will be some of the coldest air we've seen on October 31st in a few years.
First the setup. Fresh off a potent cold front on Monday, a reinforcing shot of Canadian air arrives Thursday as a second cold front drifts through the upper midwest. Clouds and isolated showers will return throughout the day. Click the image to see the progression of this next disturbance.
In behind the cold front is a fresh batch of cool air. It will easily be our coldest of the short fall season to date. But in truth, we've been kind of spoiled the middle of October with warmer than average temperatures. Still, it's a bit of a shock to the system. Highs will be in the upper 30s on Halloween. Lows, in the 20s.
So how does that stack up with Halloweens of the recent past? Looking back nearly a decade shows that Halloween 2014 will be the coldest since 2006. As of recent, the trend has been fairly constant with typical temperatures to the period. Average high/low on October 31st is 51/34.
While we'll the mercury will be slipping a bit this year, one streak we'll keep going is Halloween being dry. Measurable rain hasn't fallen on Halloween since 1997 or snow since 1995. This certainly bucks the trend as over the last 100 Halloweens, 32 had measurable (0.01" or more) rainfall.