CBS19 Weather Blog: Could we see another blast of Arctic air in February?

CBS19 Weather Blog: Could we see another blast of Arctic air in February?

TYLER, Texas – Is another round of Arctic air heading our way?

Let’s explore the possibility of an extremely cold shot of air arriving in East Texas. First of all, why do I think this is possible? A similar weather pattern developed in late November and returned in mid-January.

Credit: CBS19

Long-term weather pattern cycling, or LRC, theory tells us when key features in global wind cycles will repeat. So, the weather pattern that produced the first real taste of cold air in late November and arctic air in January should return at the end of February.

But how cold will it be this time? It’s hard to imagine it getting as cold as January, but it’s not unlikely. Why? Let’s explore something called the Arctic Oscillation. The AO index can be measured either negatively or positively.

When the Arctic Oscillation is positive, strong west-to-east winds move at an altitude of about 20,000 feet, keeping cold air confined over northern Canada.

Credit: CBS19

But when the AO becomes negative, the jet stream weakens and allows bitterly cold air to invade the United States.

Credit: CBS19

Where is the evidence that this will happen again by the end of February? The Arctic Oscillation follows roughly the same cycle length as the long-term cycling weather pattern theory for the year.

We’ve seen the Arctic Oscillation be negative the past two times, with it getting cold both times in East Texas. Forecasts expect this weather pattern to occur again around the third week of February.

Credit: Weather Service National Climatic Prediction Center

Remember the winter weather forecast aired during our winter weather show, “Cold Snow” on January 12, which called for above-average precipitation in February and another blast of cold air during the second half of the month.

This is the cold snap we’ve been expecting. Long-term computer models are now beginning to show cold air flowing into the central and southern Plains.

Credit: CBS19

There’s also plenty of cool air to work with by mid-month. Alaska has seen very cold air recently and Arctic air is expected to extend into northern Canada by mid-month. This will create an excellent source area for Arctic air once the Arctic Oscillation becomes negative.

Credit: CBS19

All of these factors point to another wave of very cold air. However, there are a few things that keep this Arctic aerial invasion from being a smash hit.

1) Lack of snow over the United States. Only the intermontane West, Rocky Mountains, and northeastern United States have significant snow on the ground. This is important because when cold air moves south, it tends to warm as it moves away from its source area. The snowpack would keep the cold air cool as it moves into the United States.

2) Upper level winds may become unfavorable to cold air flowing all the way into South Texas. Instead, we could see an undulating jet stream that will bring severe weather by the end of the month. So, for now, let’s leave it as informal weather forecasting in the Arctic and keep an eye on these key factors.

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