FIRST ALERT: Winter 2020-2021 outlook
(WBRC) - La Niña continues and there is an 85% chance it will last through the winter. The equatorial Pacific Ocean temperatures are below normal and that creates changes in the atmosphere.
La Niña disrupts the jet stream, and it tends to dip across the Pacific Northwest and Upper Midwest which results in below normal temperatures. A southwesterly flow to our north tends to result in warmer than normal temperatures in Alabama.
Here’s a look at the average high and low temperatures for the winter months:
La Niña winters in Alabama tend to have drier than normal weather, especially south. Wetter than normal conditions tend to set up closer to the jet stream to our north.
Here’s a look at the average amount of precipitation we see during the winter months:
Everyone is always so curious about whether we will see snow but before we get to the forecast, let’s talk about years past. The snowiest winter seasons in Birmingham have not occurred during a La Niña winter. We have seen snow though during La Niña winters, especially in 2017 and near average amounts in 2011 and 2009.
On average, Birmingham sees about 1″ to 2″ of snowfall each winter which is a 30-year average. Predicting snow is tricky and it’s impossible to pinpoint where snow might fall months from now. Just think about how much the weather varies over a 160 mile stretch from the western portion of the WBRC First Alert viewing area to the eastern or from the southern portion to 130 miles north.
Here are two examples as to how much it can vary. The La Niña snow event that occurred in January of 2018 produced 3″ snowfall amounts in Montgomery and just trace in Birmingham. The year before that, 8″-12″ of snow fell in December of 2017, meanwhile northwest Alabama hardly saw any snow. So again, it’s impossible to know what areas will see snowfall months in advance because it’s random.
After looking over what happened during previous La Niña winters in Alabama, here’s the WBRC First Alert Winter Outlook for Central Alabama:
We predict warmer than normal temperatures but remember that means over a 3-month period. We’ll see the jet stream dip on occasions and give us some cold snaps.
Precipitation should be around average between the 3 months. Unfortunately, there is a correlation between a strong La Niña and an increase in severe weather events in The South and so because of that we predict 3 severe weather events.
I wish I could say for sure if we all will see a little snow this winter, but I can say the odds are slightly in the favor of snow lovers. We predict a 6 out of 10 chance for snow this winter.
Jill Gilardi WBRC First Alert Certified Meteorologist
Copyright 2020 WBRC. All rights reserved.