Roller Coaster Temperature Ride

The weather pattern we’re locked into right now is one that features large temperatures changes over our region every several days. A few days of 20s and 30s are soon followed by the 40s and 50s, and so on. The movement of weather systems across the country in recent weeks has created spells of “anomalous” weather that just haven’t stuck around that long. The forecast models are indeed suggesting this kind of regime will continue for the next 1-2 weeks at least. As they say in Kansas, if you don’t like the weather, wait a few days.

Part of the reason for the big temperature jumps is the fact that we’re sitting very near the dividing zone (or front) that separates Winter from Fall. As disturbances move along the front, which they tend to do, they deform it like a wave rolling along the ocean. After spending a few days in the trough (cold part) of that wave, we’ll get near the crest (warm spot) for a bit. Without those transient systems slowing down, and without substantial movement of the frontal zone they’re tracking along, around and around we go. Like a broken record.

Perhaps the most consistent meteorological feature of this pattern has been the lack of precipitation. A surplus of rain over the Spring has turned into a deficit of nearly 5 inches for the 2010 calendar year. And as we look into the forecast model solutions for this upcoming week, it’s quite possible that any rain or snow we do get will not be significant.

Aside from providing us with sunny days and clear nights, the dry pattern has also been responsible for allowing our morning lows to plummet well beyond what a typical diurnal swing would give us. Cloudless days with high temperatures in the 40s have been accompanied by lows in the lower teens -not the middle 20s that one might expect with a high of 43. Clear skies, light winds, and a dry atmosphere are the perfect recipe for very cold nocturnal temperatures near the ground.

Until there is a shift in the global circulation, which doesn’t look like it’ll happen in the next 1-2 weeks, it’s a good bet to figure on a dry December with some good cold shots and a warm burst here and there. Status quo.