It’s that time of year again! The WRAL Severe Weather team is ready to unveil our winter weather predictions. This year, we analyzed four key factors: La Niña, accumulated cyclone energy or ACE, Siberian snow cover and climate trends.
According to the National Oceanic and Atmospheric Administration (NOAA), there’s a 60% chance that a La Niña will develop later this month.
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In La Niña years, storm tracks stay north of our region and keep the colder air farther north. Sixty-four percent of winters during La Niña result in below-normal snowfall and above-normal temperatures for us. So, for snow lovers, it doesn’t look promising.
Since 2000, we've experienced 16 years of above-normal accumulated cyclone energy or ACE, with 10 of those years seeing below-normal snowfall. This year, the tropics have used up a lot of energy.
The atmosphere operates on a finite "energy budget," and this year hurricanes consumed a significant portion of this budget by transferring heat toward the poles. This imbalance leads to fewer winter storms.
Siberian snow cover reflects 70 to 80% of the sun's heat back into space. Studies have found a strong correlation between the extent of snow cover in Siberia in October and winter storms in the eastern United States.
When Siberian snow cover is below normal in October, it often leads to a stronger polar vortex, which tends to keep cold air locked at the poles, resulting in milder winters for North Carolina.
A weaker polar vortex can create a more erratic polar jet stream, allowing colder air to push farther south. This October, Siberian snow cover was below normal, suggesting the coldest air gets stuck at the poles — more bad news for snow enthusiasts.
If you’ve been in North Carolina the last several years, you know that snow has been hard to come by. In fact, we have seen a steady decline in snow totals over the last 75 years.
The average annual snow for Raleigh over the last 75 years was nearly 7”. The average over just the last 5 years was a measly 1.7”.
For the first time in history, there was no measurable snow at RDU last winter. Looking at climate trends alone suggests we will have very little snow this year. If you are a snow lover, you should likely plan a trip to a snowier place to get your fix. We are forecasting up to about 1” of snow this year. And overall, we expect temperatures to be warmer compared to normal.