Much-needed rainfall is finally greening up Minnesota after weeks of unusually warm, dry weather. That's good news.
But down the line, heavy rain may be more common — and less welcome. Longer-trend climate models indicate that the state will get a lot wetter in years to come.
The Twin Cities metro area is already on track to break monthly rainfall averages for April after just one week, according to Eric Ahasic, meteorologist at the National Weather Service.
Average metro-area rainfall for April is about 2.3 inches, he said.
By Friday, rainfall at the Minneapolis-St. Paul International Airport, where official measurements are made, stood at 1.5 inches. The highest amount of rainfall for April was recorded in 2001, at 7 inches.
"People are cheering for it. This is a welcomed rain," said Kenny Blumenfeld, senior climatologist at the Minnesota Department of Natural Resources. He described the rain as "well-behaved," because the on-and-off showers gave the ground plenty of time to soak it all up.
Despite recent rains, no major river flooding is expected this spring.
The warm spring melted the snowpack early this year, lowering water levels and drying out the ground before spring rains arrived. That created a springtime drought.
This past week's thunderstorms and the unusually warm temperatures that preceded them aren't typical for Minnesota in April, Ahasic said.
"We've been in an anomalously warm pattern," he said.
Longer-term trends show the state is likely to get a lot wetter in the future due to a changing climate from warming temperatures, scientists say. The state has seen the most dramatic changes in its climate over the past 20 years.
In 2016, Minnesota broke precipitation records with 40.32 inches, according to DNR climate data. In 2019, the state broke the record again, with 43.17 inches over the entire year.
Before 2016, Minnesota had never had more than 40 inches of precipitation in a year since it began collecting climate data in 1871.
"Ultimately, what it comes down to is that our measuring for precipitation hasn't changed too much," Ahasic said — buckets and rulers. "You wouldn't expect too much of a change just because of different ways of measurement."
Since 1895, Minnesota has become increasingly warmer and wetter, according to the DNR. The average annual precipitation has increased by 3.4 inches since then, while the weather has warmed by an average of 2.9 degrees from 1895 to 2017.
Rain isn't becoming more frequent, but the downpours have been heavier. Torrential rains create pools of water that turn into runoff and go directly into lakes, rivers and streams.
"The really heavy rains aren't as beneficial as a long, soaking rain," said Blumenfeld. "It rains so hard that any possible benefit from it is wasted because it doesn't soak into the ground."
Alex Chhith • 612-673-4759