By Beth Spain
Red and yellow leaves mark the beginning of fall, but just before October started, record-breaking temperatures in the 90s sent confusing signals to West Tennesseans.
History shows West Tennessee weather can be unpredictable, especially for the Jackson area. Danny Gant, National Weather Service meteorologist in Memphis, explained this trend.
“The atmosphere is in a vicious cycle trying to balance itself out,” Gant said, describing the difficult factors contributing to the weather.
La Niña and El Niño are terms used to describe unusual oceanic surface temperatures in the Pacific Ocean near the equator. La Niña refers to cold ocean temperatures, while El Niño refers to warm ocean temperatures.
Gant said those surface temperatures play a role in subtropical and polar jet streams, the two main jet streams affecting fall and winter in the United States.
Gant also said the jet streams, paired with the orientation of the sun, dictate the seasons, and the polar jet stream “is the main influence for severe weather.”
La Niña winters are more impactful because more active, severe weather happens at its peak, around December and January. Gant said memorable severe weather connected with La Niña in Jackson include the 1999 and 2008 tornadoes.
La Niña has recently strengthened, according to the National Weather Service’s Climate Prediction Center.
Bill Borghoff, general forecaster for the NWS in Memphis, said this would likely increase hurricane activity, though the season is at the halfway mark.
However, unless the storms make landfall, Borghoff said October weather should be dry with a slight chance of above normal temperatures.
Borghoff said a traveling cold front will likely knock out the 90-degree weather for the rest of the season.
“Meteorology is fascinating,” said Dr. Bill Nettles, professor of physics and chairman of the department.
The Physics Department’s weather instrument, on top of the Fred DeLay Gymnasium in the Penick Academic Complex, provides timely weather readings for the greater-Jackson area.
Nettles said the instrument makes accurate nominal predictions once a day, based on barometric pressure and trends in its stored data. The instrument also calculates the sunrise and sunset each day. Interestingly, Nettles said the computer recorded a 70-mph wind burst before the 2008 tornado hit Union’s campus, and the burst knocked out power to the computer.
To access daily weather information, visit www.uu.edu/dept/physics, then click on “The Weather at Union.”