BIRMINGHAM, Ala. (WBRC) - Happy first day of Meteorological winter!
Meteorological winter is considered the months of December, January, and February as the weather pattern across the Northern Hemisphere becomes more amplified giving us more opportunities for cold weather.
Astronomical winter occurs on Monday, December 21, 2020. Daylight will continue to shorten until that day. Once the first day of astronomical winter arrives, daylight time will begin to increase slowly as we approach the spring months.
We are starting the first day of meteorological winter cold with temperatures in the mid 20s. Could this early cold spell be a hint of what is to come for the rest of this winter? It remains way too soon to know. One thing is for sure: Our winter’s aren’t as cold as they used to be. Let’s take a look how winter (December, January, and February) has trended warmer over the past five decades.
We know that winters will fluctuate with days seeing above average temperatures and days below average. We will always see cold spells in the winter. One thing we have noticed is the duration of winter events are not as long-lived as they were back in the 70s and 80s.
According to Climate Central, winter is the one season that has warmed the most since 1970 for the United States. The image above is showing how winters have warmed since 1970 across the United States. The darker the red color, the warmer it has been. Notice parts of the Northern Plains, Midwest, and Northeast have seen the most warming over the past 3-4 decades.
Winter is the fastest warming season for Alabama with temperatures over 3°F above average. Spring and summer are a close second with temperatures shy of 2°F above average.
Birmingham has seen 13 more days with temperatures above average since 1970. Notice the trend continues to show warmer average temperatures through time. Yes, we will see winters that are colder than average, but the trend has been warmer than average.
Do you think temperatures haven’t been as cold as they used to be? I’ve calculated how many times we have seen temperatures in the single digits or colder since 1960. Here’s the total times we have seen temperatures at 9°F or colder per decade in Birmingham, Alabama:
Notice we have recorded 33 days with temperatures colder than 10°F before 1990. Since 1990, extremely cold days have shrunk considerably. Note that two days from the 2010-2019 list were from the epic “snowpocalypse” that occurred in January 28, 2014 when ice, snow, and frigid temperatures wreaked havoc across Central Alabama. Temperatures dropped to 9°F on January 28th and 29th, 2014.
Usually when we see extremely cold temperatures, it normally occurs with a lot of snow cover to our north to help spread arctic air into our state. Normally cold air moderates and warms slightly as it travels to the south. When there is snow on the ground, the cold air that travels south does not moderate as much and can remain cold.
Can a warm winter be a good thing?
A warmer winter can have negative impacts. One negative impact for Alabama is the number of freeze days needed for particular crops. The peach crop requires a certain amount of freeze hours for healthy development. If we don’t see enough freeze hours, it can really hurt farmers. It hurts consumers as prices increase due to the demand of a product. In colder regions that are seeing less snowfall, it can hurt the tourist and sports industries that depend on the snow for skiing and sledding.
Now you know how a warming Earth can contribute to our winters here in the Southeast. Once again, it does not mean we won’t see snow or cold spells. They will continue to happen. It’s a matter of when.
Have a happy (meteorological) winter everyone! If wintry weather impacts Alabama, we will let you know on WBRC and through our WBRC First Alert Weather App.