Story at a glance
- Amid hot summer temperatures, tornado warnings and forecasts have declined from usual May and June averages.
- Scientists credit this to overall dry conditions.
Weather forecasts anticipate scorching summer temperatures across the U.S. but also reveal an interesting trend: during this past May and June, only 248 tornadoes touched down nationwide — a record low.
USAToday reports that this is due to overall dry weather conditions and other patterns.
For tornadoes to form, a combination of moist, hot air meets chillier winds and tends to arrive with thunderstorms. Having a dry spring implies that conditions were not humid enough for a tornado to form.
“There was high pressure over the East Coast, which kept cold fronts to the north, keeping the warm air in the Plains through the East,” Alan Reppert, senior meteorologist for Accuweather, said.
When dueling hot and cold winds do not meet in storm-like conditions, tornadoes are less likely to form.
This is a welcome reprieve when looking back at early Spring months; in April, at least 30 fatalities were recorded as about 140 tornadoes struck the southeastern U.S. during the Easter holiday.
In contrast to 2019's monthly average of 269 preliminary tornado warnings, USAToday cites data 140 this past May. Similar figures were reported for June.
Despite the good news, experts warn against complacency.
“We cannot state with confidence, though, what the remainder of the year will look like,” said Bill Bunting, the chief of forecast operations at the National Weather Service Storm Prediction Center. “We might expect to see more extreme weather in the fall, but we can only make a 10- to 14-day prediction, so we usually look at history.”
Bunting also added that though the quantity of tornadoes has declined, the strength of ones which do form are consistently strong, ranging from EF0 to EF2 — the Enhanced Fujita (EF) scale that rates the intensity of hurricanes from 0-5 — threatening residents with maximum wind speeds of 135 miles per hour.
To best prepare for a tornado, Bunting recommends monitoring forecasts and having an emergency plan.