Before the phrase “polar vortex” became popular, Arctic air was known to the Gulf Coast.
In an Arctic outbreak of February 13, 1899, Mobile reached an all-time low temperature that morning of -1 degree. That’s one degree below zero. That afternoon, the high temperature only reached 21 degrees. This data comes from the Period of Record Data Tables for Mobile at the Southeast Regional Climate Center.
A typical morning low temperature in Mobile on February 13 is in the lower 40s, while a typical high is in the lower 60s.
Mobile was not alone in the bitter cold air in February of 1899. It became known as the Great Arctic Outbreak, and according to NOAA, “The Great Arctic Outbreak didn’t just bring cold to the nation. It also brought snow and ice and lots of it. By the time blizzard conditions ceased in the Mid-Atlantic and Northeast, Cape May, New Jersey, record over 30 inches of snow, as did Washington, DC, and Baltimore, Maryland. On February 17, ice was even witnessed flowing down the Mississippi River, past New Orleans, and into the Gulf of Mexico. And, a one-inch thick layer of ice formed at the mouth of the Mississippi in East and Garden Island Bays in Louisiana.” Read the full account here.
In the image below from Monthly Weather Review, you see monthly low temperature readings for Daphne, Alabama and Evergreen, Alabama at zero, and in Citronelle, Alabama, there was a low temperature reading of two degrees below zero.
If you are curious about temperature and rain extremes in Mobile, see the list right here.
Arctic outbreak or polar outbreak are more accurate terms to describe the coldest air that leaves the Arctic and heads southward through the United States during the winter. The polar vortex is a continuous river of air at high latitudes that does contain polar air but the actual vortex is more than 10 miles above the ground, so the name may be a little misleading when it’s applied to cold air outbreaks.
Note: there are no weather instrument records before the 1800s for Mobile so there could easily have been colder days before then.