Unusually warm, humid weather helped spark Arkansas tornadoes

At least two Arkansans died Friday due to tornadic activity that started northeast of Little Rock and cut through parts of five other states.

• Gov. Asa Hutchinson declared a state of emergency, giving the Arkansas Division of Emergency Management $100,000 to assist with response and clean-up.

Driving the news: December tornadoes are not unheard of, but an event of this scale and ferocity is potentially unprecedented for this region.

• A strong cold front and area of low pressure created "a fairly classic setup" for tornadoes, meteorologist-in-charge Jim Reynolds of Little Rock's National Weather Service told Axios.

Threat level: Another warming trend is coming next week for the eastern U.S. According to the National Weather Service (NWS), some areas of the country may see temperatures running 20°F to 40°F above average for this time of year.

The big picture: Winter is warming faster than other seasons due to climate change. This year has the potential to be the warmest December on record for many areas, writes Axios' Andrew Freedman.

• Additionally, meteorologists have observed more instances of unusually strong, stubborn areas of high pressure in recent years that have been associated with extreme weather events, including heat waves.

What they're saying: Reynolds told Axios that this week's warming trend will bring some moisture with a fairly low chance of precipitation, but that NWS isn't expecting anything like Friday night or Saturday morning.

• All residents of Arkansas should be prepared for severe weather during any month of the year.

Andrew's thought bubble: Climate scientists studying how tornadoes may be changing in a warming world are focused on trends in their main ingredients. As the world warms, there is a greater supply of atmospheric instability, with warm and humid weather occurring more frequently, even in the cold season. This could favor severe thunderstorms.

• Studies show when such ingredients overlap with abundant wind shear — i.e., winds changing direction or speed with height, along with a trigger like a cold front — then large outbreaks can occur.

• Overall, there is increasing evidence that tornadoes are becoming more common in the South Central and Southeastern states, as traditional "Tornado Alley" sees a decrease in tornado days. This has tremendous implications for peoples' exposure to risk, given population growth in the region.

Go deeper: Subscribe to the free Axios Generate newsletter for more.

Plus: How to help

Several rural towns impacted by the storms will be in the process of rebuilding for the next several weeks.

How you can help: The American Red Cross of Missouri and Arkansas is working to help tornado victims. To learn how to volunteer, visit redcross.org/volunteer. You can donate at redcross.org, by calling 1-800-733-2767 or texting REDCROSS to 90999.