A Little Spring in December
Saturday, December 13th 2014, 8:45 PM CST
While there's a defined severe thunderstorm season in Oklahoma, there's never fully an “off-season” for that kind of weather. Case in point is Sunday's chance of storms, a few of which could reach severe limits. The overall threat is low, especially compared to that of a spring day where there's greater daytime heating. However, you won't want to let tomorrow's threat catch you off guard.
A powerful storm system, centered near the Four Corners Saturday evening, is barreling its way eastward. The attached map shows how this system resembles a bowling ball. It's a compact, but potent piece of mid-level atmospheric energy that will easily fire showers and storms as it advances into the moist air mass in Oklahoma on Sunday. With that strong mechanism for lift, even very modest instability can create some powerful little thunderstorms. It's a fast-moving weather pattern so these showers and storms will come at us fast. Showers will be ongoing Sunday morning over western Oklahoma, advancing to the I-35 corridor midday and arrive around Tulsa by mid to late afternoon. Temperatures will steadily warm into the 60s by then and any additional heating could increase our risk of severe weather.
The most likely threats from these storms will be gusty winds and hail. A tornado can't be ruled out with lots of spin (also known as wind shear) in the atmosphere. However, it appears unlikely at this point due to the lack of heating. For many of us, it'll just be a good rain with perhaps a few gusts of wind and claps of thunder. Just remember, even in December, we need to be prepared to take severe weather precautions when necessary. A second line of storms may develop behind the leading line Sunday evening, offering another round for heavy downpours. All of this should clear the state line by midnight or so.
Cooler air will be delayed a bit behind this system. Being of Pacific origin, it hasn't latched on to much Arctic air. It will simply bring our temperatures to near normal levels with highs in the upper 40s and lows around or just below freezing starting Monday. However, Sunday's system is just the first in a series coming our way for the following week. Wet weather returns as early as Wednesday and could last until the weekend. Fortunately, our air will be just warm enough to prevent wintry weather. However, we can't rule out a few flakes of snow sneaking into parts of Green Country Friday evening as the final system exits the area.
Finally, we're close enough to Christmas to have a *broad* idea of what the weather will be like. For now, it appears a warmer than normal, but a wetter than normal pattern will continue. While we can't rule out snow, the chances of a White Christmas are very low since the Arctic air will likely remain locked into place with a split jet stream pattern for the foreseeable future. (Refer to the 2nd map). Lots can change in 12 days though, so stay tuned!