2012 may be one of driest years on record
CHAMPAIGN — So far, 2012 is on pace to be one of the driest years ever in Champaign-Urbana weather history.
Including Sunday's brief rainstorm, the Illinois State Water Survey has reported 14.18 inches of precipitation so far this year. Normal through the first six months of the year is about 20 inches.
In every month this year, except January, precipitation locally has been below normal.
Central Illinois is already in what National Weather Service meteorologist Ed Shimon called "a severe to extreme drought."
"It's definitely catching some eyes now," said Shimon, of the weather service's Lincoln office.
"Even if we return to near normal for the rest of the year, we'll probably be well below normal for 2012," Shimon said. "We'd have to be significantly above normal for the rest of the year to break out of this."
Over the last 12 months, according to the East Central Illinois Regional Water Supply Planning Committee, there have been about 32 inches of precipitation, 7 inches short of normal.
The group is urging area residents to "be prepared for a more severe and longer drought than we are experiencing currently" and suggested that they begin taking steps to conserve water.
In the driest year in local weather history — 1901, when there was 28.64 inches of precipitation — Champaign-Urbana recorded 14.63 inches of precipitation during the first six months of the years. Only in 1914 — the fifth-driest year ever — did the community receive less precipitation (12.57 inches) than during the first six months of this year.
Meanwhile, the rainfall outlook for the next two-and-a-half months is not encouraging. The Climate Prediction Center of the National Weather Service forecasts the drought to persist or intensify for almost all of Illinois through Sept. 30.
The best hope for an end to the drought, Shimon said, is for a tropical storm or the remnants of a hurricane to move into the region.
"Once you start the drought process, if the moisture in the ground isn't able to feed back into the atmosphere when precipitation moves into an area, it basically evaporates before it hits the ground a lot of time, because you don't have that feedback making it from the cornfield and the ground itself," he said. "Drought breeds drought is one of the sayings we have here. It's a tough cycle to break unless you get something like a tropical storm from Texas coming into our area to give us three or four days of rain. That usually is a solid drought-breaker."
A hurricane is less likely, he said.
"That would definitely do it, but hopefully we won't have to wait for that because we haven't had a major landfall hurricane in six years in the United States," Shimon said. "That's a Category 3 or greater, and we haven't had one since 2006."
He explained that the mild weather pattern, which began last winter, is partly responsible for the drought.
"We got into a more summertime pattern much earlier this year with the jet stream sliding north sooner than normal. And that kinda took us out of the heavy rain cycle we typically see in the April-May time frame," Shimon said. "In June we usually see a decent amount of severe weather and rainstorms moving across central Illinois. June is usually one of the highest rainfall months of the year, but we just missed a lot of storm tracks as they were farther north this year.
"It's just an unfortunate series of events where we had a warm spring and now we're having an unusually warm June and July. And that means we're usually out of the area where the frontal boundaries reside and that means less precipitation. There have been some hit-and-miss showers, but it's just not enough to break through."
He said he's hopeful for some rainfall in central Illinois over the next week, although the official forecast doesn't mention rain.
"The front has dropped down to the Ohio Valley now, but it's supposed to creep back up. Maybe by Saturday or Sunday we'll have a better chance of storm tracks creeping back north to our area from Tennessee or Kentucky," he said.
The most recent drought years in central Illinois were 1991, when Champaign-Urbana received 34.87 inches of precipitation, and 1988, when it got 29.61 inches. If the drought continues at the current rate, total precipitation for the year would be less than 28.5 inches, placing it fourth in local weather history.
A dry year by the numbers
This chart shows actual and normal rainfall (in inches) by month for Champaign-Urbana, and the difference so far this year. Information is from the Illinois State Water Survey.