Warmer-than-average temperatures to continue, meteorologists say
From Staff and Wire Reports
As weather resembling that of an early summer day beat down on Blount County Wednesday, it just might leave some wondering — have we skipped spring?
One thing is certain, meteorologists at the National Weather Service in Morristown say residents should prepare for warmer-than-average temperatures in the coming weeks.
Meteorological Intern Kate Guillet said the transition from a La Nina year — which brought lower sea surface temperatures across the Eastern Pacific — has contributed to the mild winter experienced this year in Tennessee. The average temperature for the month of February, which was measured at McGhee Tyson Airport, was 46.2 degrees. That’s 3.8 degrees above average, Guillet said, and it tied February 2011 as the 24th warmest on record.
And as far as what to expect in the coming weeks?
“There’s the possibility that we will get another cold snap,” Guillet said. “But for the next week or so we will expect warmer than average temperatures.”
As for spring flora and fauna, many have already started to bloom. And another cold snap could be rough on those early bloomers.
If Blount County does experience another cold snap before spring, those with a green thumb should be prepared.
“Just do what you would do with a normal freeze,” Guillet said. “Cover them or take them inside.”
But the rest of the week is certainly out of the question when it comes to winter throwbacks, with forecasted highs straddling the high 70s and even an 80-degree day expected on Sunday.
From the Mississippi River to the Smoky Mountains, the winter that just ended was warmer than usual all across Tennessee.
Forecasters use the meteorological stretch of December-February rather than the astronomical period between the winter solstice and the vernal equinox to denote the season.
Above normal statewide
It was the mildest winter in Nashville in 40 years, averaging 4.3 degrees above normal.
The National Weather Service reported the winter was 4.5 degrees above normal in Memphis. Knoxville and Chattanooga both ended the season at an average 4.4 degrees above normal while the Tri-Cities had a relatively balmy 4.6-degree deviation to the plus side.
In a sense, the unusually mild winter was something the wind blew in.
“When we have a La Nina situation like we did during the winter months, the main branch of the polar jet is well north of the Tennessee Valley,” said Bobby Boyd, a meteorologist with the National Weather Service office in Nashville. “The southern branch is moving across the Desert Southwest, the Southern Plains and the lower Mississippi Valley, bringing us warmer temperatures.”
La Nina and El Nino are the opposite phases of surface temperature variations in the Pacific Ocean.
In the La Nina, or cold phase, winter temperatures in the continental U.S. are warmer than normal in the Southeast and cooler than normal in the Northwest.
Another weather phenomenon also came into play.
“Arctic oscillation was in a positive phase,” Boyd said. “This year, most polar air spilled into Europe and Russia.”