A kinky jet stream will bring a week of extreme weather to the United States, promising a grab-bag of atmospheric excitement that ranges from mountain snows and Plains tornadoes to the East Coast’s first decent heat wave of the season. The coming storm systems exemplify the feast-or-famine nature of springtime weather, especially as we get closer to the peak of tornado season at the beginning of June. You might either be begging the sky for a little water in your garden or sprinting for your basement as yet another tornado warning blares from your cell phone.
Most of the significant weather events we experience throughout the year are the result of the jet stream, a fast-moving river of air that generally makes itself at home around 30,000 feet above sea level. It doesn’t seem like winds roaring along six miles above our heads can make much of a difference on the ground, but winds that blow in the middle- and upper-levels of the atmosphere are the driving force behind just about every major weather feature.
These upper-level patterns are the reason it’s going to get toasty along the East Coast this week. High temperatures in the 90s are likely as far north as New England as a ridge of high pressure builds in place. Ridges, or northerly kinks in the jet stream, are the reason heat waves can get so intense. Ridges foster subsidence, or sinking air that clears the sky of clouds and makes the air quite toasty. The buildup of air at the surface leads to the formation of a high-pressure center. The more intense the high-pressure, the more intense the heat wave. It’s neither uncommon nor unprecedented to see summer-like heat in May, but it’s still uncomfortable nonetheless. The heat will be accompanied by humidity on Thursday and Friday, so those high temperatures hovering around the 90°F mark will feel even warmer thanks to the heat index.
Ridges are resilient. They don’t like to budge once they form, and this often leads to unsettled weather along the outer periphery of high-pressure systems. Several troughs will dig south out of the Rocky Mountains this week and lead to multiple opportunities for severe weather and heavy rain in the Plains and Upper Midwest. Significant severe weather is possible on Tuesday in the area traditionally known as Tornado Alley—storms from western Texas through western Nebraska could produce some violent tornadoes on Tuesday afternoon. More severe thunderstorms are possible in the central United States toward the end of the week.
One the storms are finished tormenting the central Plains, they’ll continue raining as they travel around the edge of the heat dome over the East Coast. NOAA’s Weather Prediction Center expects that two to four inches of rain will fall across a swath of land from central Texas to Lake Superior, falling over areas that really don’t need rain these days. Rivers in the Midwest are still trying to recover from flooding rains earlier this month. Any additional heavy rainfall will make the situation worse. Precipitation at higher elevations in the Rocky Mountains will fall in the form of snow, with mountain peaks possibly seeing several feet of snow before the weather settles back down.
The lack of rain is making things worse in Florida, where the resilience of the ridge and prolonged summer-like heat will send Florida and Georgia deeper into drought. While the rest of the country has largely recovered from any sort of lasting drought, the extreme southeast hasn’t been so lucky.
Large sections of Florida were in a severe or extreme drought according to the U.S. Drought Monitor’s update on May 11. The dryness isn’t only affecting agriculture—it’s also allowing wildfires to quickly spread out of control.
A lightning strike at the beginning of April sparked the West Mims Fire, a blaze located right on the border between Florida and Georgia northwest of Jacksonville, Florida. Officials reported on May 15 that the fire had burned about 237 square miles of land—an area more than three times larger than Washington D.C.—and was only 18 percent contained. Crews likely won’t receive any natural help in fighting the fire until the weekend, when the stubborn weather pattern breaks and showers and thunderstorms are once again possible.