Wednesday, November 4, 2009

A Milder Month?

An analysis of midwestern weather records shows that following a cool & wet October, we typically see an about-face in November.  (Although some chilly temps will occur, the overall monthly average will come out above normal.)

One factor that supports this is the effect from El Nino.  In periods with strong El Ninos (like the one currently in the Pacific), autumns tend to start cold and then modify a bit...leading to a winter with above normal temps and below normal precipitation.  This does not mean the winter will be warm.  In fact, big cold spells do occur like a normal winter.  However, there tends to be less frequency and duration of them.

El Nino modifies the position and movement of the normal winter jet stream patterns.  This allows for the variations between cold and not-so-cold periods, plus less frequent storms (leading to below normal precip).  We still see snow, just not as much as a normal winter.

In the short term forecast, after a cold start Friday morning, temperatures will modify nicely over the weekend.  Some slightly cooler weather should move in Tuesday of next week, but temps will warm back up a bit later next week.