For weeks, winter weather has evaded North Texas.
Temperatures have regularly been 10 to 20 degrees above normal. At least six new daily heat records were set. And each time a cold front has moved in, it hasn’t lasted long before warm conditions returned.
December began with some notable chill, but it quickly vanished, leaving behind daily highs in the 70s and 80s for much of the holiday season, according to the National Weather Service’s Fort Worth office. As the start of meteorologic winter, December doesn’t usually contain the season’s coldest days, but the lack of crisp air has been particularly prominent. This abnormal winter warmth also comes on the heels of an unusually warm fall in Dallas-Fort Worth.
D-FW Weather Wise
John Nielsen-Gammon, the Texas state climatologist, said this unusual heat has been affecting more than just Texas. Much of the central United States has been hotter than normal in recent weeks, while the Pacific Northwest and New England have seen colder winter weather.
He largely attributed this pattern to the movement of the jet streams, which are narrow bands of strong wind currents that blow from west to east around the planet. Those bands form on the boundary between warmer and colder air masses, and can affect the movement of weather systems across the country.
The current shape of the jet stream is called a Pacific-North America Pattern, Nielsen-Gammon said, and often leads to opposite weather trends in the northwestern and southern United States.
But it’s not just the jet stream – human-caused climate change is making all seasons about 2-3 degrees warmer.
“Which, in itself, is small,” Nielsen-Gammon said. “But in many places it has essentially been enough to put things beyond the record threshold.”
Andrew Dessler, Director of the Texas Center for Extreme Weather at Texas A&M, said repeatedly breaking climate records — whether with floods, winds or temperatures — is “the siren song of climate change.”
“Eighty degrees in December, it’s actually pretty pleasant,” he said. “Just realize the same temperatures that are making this pleasant are going to make August incredibly unpleasant.”
In good news, chillier air is inbound.
A cold front is expected to move in Friday evening, which will drop daytime highs down to the mid-50s over the weekend. More normal temperatures for January are expected to continue the second week of the month.
Sarah Barnes, a meteorologist with the weather service, noted that it’s “still pretty early” in the winter season and said winter precipitation could still be on the horizon. The Climate Prediction Center is forecasting above normal chances of precipitation later this month, but it remains to be seen if it will be cold enough for flurries to form.