While snow itself is an uncommon phenomenon on the Gulf Coast, the freezing rain and sleet that fell over the area during the past two days was a “once-in-a-20-30-year event,” according to Jason Beaman, a meteorologist at the National Weather Service in Mobile.
“We looked at the record books and even further north it’s not very common because sleet is typically a transitional thing, falling just before it snows,” Beaman said. “What was interesting wasn’t the upper-level pattern in the atmosphere, that’s not too unusual. More than 99 percent of the time this would just be a light to moderate rain event, but we had a strong surge of arctic air right ahead of the upper level system, so it was perfect timing for sleet and freezing rain. It’s really unique and historic for this area.”
Beaman said the precipitation didn’t fall as snow because a layer of air about 4,000-6,000 feet high was warmer than 32 degrees. He also said the storm was related to a persistent upper-level pattern that brought a round of arctic air a few weeks ago and after temperatures dip into the teens again tonight, the same trough of air was expected to move westward, leaving us with warmer weather and another threat.
“With warmer air moving over the cold water, we’re looking at possibly having some heavy fog this weekend,” he said.
Officially, lows fell to 19 degrees in Mobile Jan. 29 while as much as 1.5 inches of ice accumulated on roads. Power outages were few and far between, but driving conditions were expected to remain poor until temperatures rebounded midday Thursday.