Sept. 25, 2017
You bet it's wet: Yearly rain total nearing 6 feet in Southwest Florida
By Chad Gillis
Southwest Florida is nearly 2 feet above average rainfall for the year, and we've already had enough rain to beat the highest precipitation totals in the past 15 years. Lee and Collier counties are just above 70 inches of rain for the year, which is more rain than has fallen in a single year in more than a decade. And there's still three months left this year.
Even 2005, the year several hurricanes made landfall in Florida, is behind 2017. The year that ended with Wilma making landfall in Collier County and brought 68 inches of rain for the year.
"We’re very wet, I know that’s an understatement but that’s kind of where we sit," said John Mitnik, the South Florida Water Management District's top engineer. "For the wet season we’re about 150 percent above average rainfall sitting here at the end of September, and we’ve still got a couple of weeks, maybe six weeks of wet season to go through. So we’ll see what the rest of it brings us."
This year has seen weather at the extremes, with the driest conditions recorded in nearly a decade bringing drought-like conditions one year after El Nino rains dumped more than a foot of rain in the dry season. To put that into perspective, this year's precipitation is nearly twice what fell in 2007, during the entire year, according to water district records.
Lake Okeechobee, the liquid heart of the Everglades, shrank down to about 11.5 feet above sea level in May, enough to cause water managers to worry about South Florida's water supply, June brought record rains. July was pretty dry. August dumped nearly 20 inches for a month that averages just more than 9 inches. Then came September and Hurricane Irma, which pushed the region over 70 inches.
Hurricane Irma dumped upward of 20 inches in localized areas, but the heaviest rain was actually on the east coast. "If you had asked meteorologists to try to predict where the heaviest rainfall (would fall) from a Category 3 making landfall on the west coast, they would not have told you Fort Pierce, so something just set up in that neck of the woods," Mitnik said. "But for the most part the heaviest rain went right along with the eye wall."
The eye wall came across the Keys and Marco Island, then pushed north through eastern Lee County. The rainy season officially runs through the end of October, although rain this month tallies less than half of numbers seen June through September.
The National Oceanic and Atmospheric Administration is calling for equal chances of below, average or below-average rainfall amounts through the rest of the year. That basically means NOAA expects conditions to be close to average, which means another 7.3 inches of rain, on average, between now and Dec. 31. "It's going to take another good month or so before we really start to get into the dry season," said John McMichael, a meteorologist with the National Weather Service in Ruskin. "It takes a transition period to do that."
McMichael said Hurricane Maria reduced rain chances by causing hot air to sink, instead of rising and forming clouds. "Irma went by and we had a period where we really had no rainfall at all," McMichael said. "Maria also dragged a lot of drier air down here so you get more of a northerly flow and it’s pulling drier air in as well."
McMichael said rain chances are low until Thursday, when chances rise to 40 to 50 percent. All the rain made up for the water shortage earlier this year. Now there's too much water in Lake Okeechobee, with levels approaching 16.2 feet above sea level.
Army Corps of Engineers protocols say the surface of the lake should be kept between 12.5 and 15.5 feet above sea level to provide flood protection for thousands living south of the lake while also providing drinking water for homes and irrigation water for farms.
Heavy rains in June, along with Hurricane Irma dumped several feet of rain on lands south of Lake Okeechobee. That means it's impossible to send more lake water south, so the Caloosahatchee River is likely to continue seeing releases from Lake Okeechobee. "As a result of all the accumulated water in the system, we’re not able to move water south from the lake into the water conservation areas because of their levels,"Mitnik said.