More thunderstorms, heavy rain expected Wednesday for flood-ravaged southern Wisconsin

September 6, 2018

After what looks to be a mostly dry day Tuesday across southern Wisconsin, storms and heavy rain are expected again on Wednesday, extending the area’s flooding woes, according to forecasters.

There is a chance for storms in northern portions of south-central and east-central Wisconsin on Tuesday, with storms becoming more widespread overnight northwest of a line from Monroe to Madison to Fond du Lac, the National Weather Service said.

An inch or more of rain is possible Wednesday across all of Wisconsin, and after a couple of dry days Thursday and Friday, the chance for storms returns Friday night through Saturday night.

That means river flooding is expected to or could continue along the Baraboo, Rock, Crawfish, Pecatonica, Sugar and Fox rivers, while there’s no end in sight to street flooding on the east side of Madison’s Isthmus where the Yahara River connects Lake Mendota and Lake Monona, the Weather Service said. Details of street impacts are in the list at the city of Madison’s website.

All four Yahara River lakes experienced an increase in water levels Monday. Lake Monona continued its push to a new historic high of 848.34 feet above median sea level, or 7.5 inches above the 100-year flood elevation, city staff said. Lakes Mendota and Kegonsa rose 1 inch by Monday morning, and lakes Monona and Waubesa rose 1.5 inches.

Mayor Paul Soglin said on Monday that “We need a week of sunshine,” for the flooding to subside.

That flooding has done tens of millions of dollars in damage across the region and closed numerous highways.

See our comprehensive coverage of the flooding here.

In Madison on Tuesday, 0.47 inches of rain was recorded at the Dane County Regional Airport, boosting the September total to 2.11 inches.

But other locales saw much more rain, with up to 3 inches to the north of Madison, with the heaviest rain falling between Lime Ridge and La Valle in Sauk County, causing new flash flooding, the Weather Service reported.

In Madison on Tuesday, there’s a 20 percent chance for showers and storms after 3 p.m., with partly sunny skies, a high near 84 and south winds at 5 to 10 miles per hour.

Overnight, the chance for showers and storms rises to 60 percent, with possible rain totals of less than a tenth of an inch, as the low falls to around 69.

Wednesday features an 80 percent chance for showers and storms, with possible totals of a quarter- to half-inch, cloudy skies, a high near 74 and southwest winds around 10 mph becoming north winds in the afternoon.

The Weather Service said much cooler weather will follow, with chances for showers and storms at 30 percent Wednesday night, 30 percent Friday night, 40 percent Saturday, 30 percent Saturday night, and 20 percent Monday.

Skies over Madison should be mostly sunny Thursday, partly sunny Friday, mostly cloudy Saturday, partly sunny Sunday, and mostly sunny Monday, with highs near 70, 69, 69, 71 and 74, and lows Wednesday night through Sunday night around 58, 56, 58, 57 and 57.

27 Storm Track meteorologist Branden Borremans forecasts a few isolated afternoon storms on Tuesday, showers and storms developing overnight, scattered showers and storms Wednesday tapering by evening, cooler and less humid weather in a mostly dry stretch to follow, with just possible showers and storms Saturday night and Sunday.

Borremans said skies over Madison should be partly sunny Tuesday, cloudy Wednesday, mostly sunny Thursday, partly sunny Friday, mostly cloudy Saturday and Sunday, and partly sunny Monday and next Tuesday, with highs near 85, 77, 72, 71, 70, 70, 76 and 79, and overnight lows around 71, 56, 54, 57, 60, 56, 60 and 65.

Monday’s high in Madison was 73 at 7:26 p.m., 4 degrees below the normal high and 19 degrees below the record high of 92 for Sept. 3, set in 1939 and 1960.

Monday’s low in Madison was 69 at 6:38 a.m., 14 degrees above the normal low and 31 degrees above the record low of 38 for Sept. 3, set in 1974.

Officially, 0.47 inches of precipitation was recorded at the Dane County Regional Airport on Monday, boosting Madison’s September and meteorological fall (September through November) precipitation total (rain plus snow converted to liquid) to 2.11 inches, 1.77 inches above normal. The 2018 total rose to 38.14 inches, 12.98 inches above normal.

Madison’s record precipitation for Sept. 3 is 1.03 inches in 1870 and 1953.

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