Nashville's winters heat up

Temperatures in Nashville will be unseasonably mild for the rest of the week, with Friday’s high expected to break into the 70s.

• Those numbers fit with a broader trend of winters in the U.S. getting progressively warmer.

Driving the news: A series of record warm air masses could make this the warmest December on record for some places, Axios' Andrew Freedman reports.

• Nashville is expected today to be well above its average temperatures for Dec. 15, which are a high of 52 and a low of 33, National Weather Service meteorologist Brittney Whitehead tells Axios.

Why it matters: Scientists say warmer winter temperatures can create conditions that make severe storms more likely.

The big picture: Every season in the U.S. is getting warmer, in line with global trends. But the colder seasons are warming the fastest.

• The average temperature in Nashville during meteorological winter, from December to February, has increased by 3.8 degrees since 1970, according to NOAA data analyzed by the climate research group Climate Central.
• In the same timeframe, Nashville has seen an increase of 11 winter days with highs well above average.