Rain will douse the area Tuesday, followed by cooler temperatures and the chance for a wintry mix of light snow by the end of the week.
A few strong to severe storms could produce brief damaging wind gusts and heavy rainfall today, with at least 1 inch expected and up to 2 inches in isolated locations, according to the National Weather Service in Huntsville.
Some showers could linger west of I-65 Tuesday evening before pushing south as colder air moves in behind the rain. Temperatures could drop into the lower to mid 30s Tuesday night.
More clouds than sun will persist Thursday, making for a raw day, with similar highs to Wednesday in the mid and upper 40s. Overnight lows Thursday night will likely fall below freezing all of the Tennessee Valley under mostly cloudy skies, according to the weather service.
Wednesday will be a chilly one, with highs in the 40-50 degree range and lows again in the 30s at night.
A reinforcing shot of even colder air will blanket the Tennessee Valley Thursday going into Friday, with midday highs in 40s before dropping into the lower 40s to end the week.
In addition to the cold, this “clipper system” will also bring the chance of wintry precipitation, starting out as light snow across northwestern Alabama Friday morning before becoming a mix, then all rain in the afternoon. The rain should mix with, then become all snow Friday night. The wintry precipitation will continue Saturday, becoming a mix during the afternoon, according to the weather service.
Overall, light precipitation amounts are expected, and a still “warm” ground will likely prevent any accumulations limited to grassy surfaces and/or colder north facing locations.
The effects of the clipper should end Saturday evening, but Arctic air will then filter into the Southeast, with temperatures dropping down into the lower 20s Saturday night. Some places could get as cold as the upper teens.
A slight warm-up is expected Sunday, with highs back into the mid to upper 40s. The normal high temperature for this time of year is the mid-50s.
A La Nina phase is likely on the horizon, according to Dr. Brenda Ortiz, an Alabama Cooperative Extension System scientist.
La Niña is characterized by unusually cold waters across the east-central equatorial Pacific, which causes warmer and drier conditions during the winter, especially in areas closer to the Gulf Coast.
During La Niña, sea-surface temperatures are generally 4-6 degrees below average. These temperature fluctuations occur between the International Dateline and the west coast of South America.
In the southeastern U.S., this phase coincides with warmer and drier-than-normal conditions during winter and spring months. During La Niña, storms move up the Mississippi Valley and Ohio Valley, which means northern Alabama and northern Georgia may have more rainfall than normal, while the rest of the Southeast remains warm and dry. However, this varies between individual events.
A La Niña phase can last as many as two to three years. Longer La Niña events have preceded some of the most severe historic droughts in the Southeast. La Niña also corresponds with a very active Atlantic hurricane season.
Ortiz and her colleagues have conducted extensive El Nino/La Nina crop research which suggests early maturity varieties of wheat do well when planted in southern counties of Alabama and Georgia compared to late maturity varieties.
Farmers should be aware of the potential wheat yield losses associated with Hessian fly damage, especially in warmer winters influenced by La Niña, according to the extension service.