Ever since our unusually warm Thanksgiving Day here in Oklahoma, colder air has settled in. These cool days and colder mornings are closer to the norm even if they are a shock to the system. However, this plunge into winter-like temperatures won't last for long. As we approach the meteorological start to winter (December 1), temperatures will be going up, not down.
We have a rather benign weather pattern as the jet streak maintains a general west-to-east track across the country with no major dips. Major dips usually equal major storm systems. Without any systems of consequences, colder air is kept bottled up to our north while mild air remains in place further south. At the surface, high pressure will shift east, inducing a long-term southerly wind. Not only will that draw up warmer temperatures, it will bring more low-level moisture. Without any storm systems to bring a significant cool-down, we will become increasingly mild as the month ends and December begins.
The increase moisture will mean a couple things. First, it will really only amount to an increase in clouds starting Thursday. Without any major storm system, there won't be anything to tap into the moisture to produce rainfall. With that increase in clouds and low-level moisture, it also means temperatures won't free-fall at night nearly as far. It will give us milder nights, but keep our temperatures in check during the day. Despite the unusually mild air mass, we might just miss out on record highs with more clouds in place. Even with those clouds, we'll likely top the 70-degree mark for this first weekend in December. Hello… spring?
Let's look further out. The attached map from the Climate Prediction Center gives us the 6-10 Day Outlook for temperature departures from normal. That big red bulls-eye in the Southern Plains confirms what the longer-range computer show – no big cool-down with fairly consistent weak ridging in the jet stream to sustain the warmth for us. There are signs this pattern won't hold much beyond this time period, but for now, winter will hold off. These warmer temperatures will also help us in the final stretch of the year to maintain our lead as the warmest year on record.
If you want it to feel a little more like Christmas, (by our standards of course) you'll have to wait a bit longer. Enjoy the upcoming bout of Indian Summer! It may feel strange to put up Christmas decorations in short-sleeve shirts, but I, for one, will love it!