When Will It Get Cold Again ?

What a difference a year makes. Summer 09 will be remembered in our region for its unseasonable chill, and the brutal winter of 09-10 was one for the record books here in Eastern Kansas. But those cold times seem a distant memory now. Since last winter, we’ve had quite a stretch of above-average temperatures in our area. In fact, monthly departures from “climatology” (a 30-year mean) have come in on the warm side since last March.

The abrupt shift from really cold to really warm across the United States (see footnote) occurred early last Spring, as the decline of El Nino -among other factors- nudged the global atmosphere toward a place that kept the warm air coming over the Central Plains. After only twenty five 90-degree days in the Summer of 09, Lawrence notched a more respectable 58 this season, in addition to eight 100-degree days. And while the pattern this month (October) has shown some tendency to bring an occasional cold front our way, none of the cooling has lasted more than a couple of days. Instead, the cool shots have been more than balanced by warm anomalies in between. Like clockwork, October is on pace to be the 8th warm month in a row.

However, there is some temporary hope for cold air lovers. And, oddly enough, it probably has something to do with Super Typhoon Megi in the West Pacific. This is because the weather over North America is often jolted when big hurricanes move out of the tropics and into the jetstream flow, just as Megi will do in the coming days. And for complicated reasons, the resulting pattern occasionally favors a southward penetration of “cold” air from Canada.

Some of the global weather models want to go this way late next week. It’s a long way out, of course, with lots of variability in the forecast yet to be resolved, but I’ve seen this big picture before. The migration of strong tropical cyclones into the westerlies can indeed be a meterologically traumatic event. But I should also mention that, because this particular event appears unaccompanied by a larger movement toward a new pattern, our consequences may not last more than a couple of days. But we’re used to that, right ?

Footnote: In the global average, however, 2009 and 2010 have been extremely warm despite the regional chill observed across the United States.*