National Weather Service forecast graphic 8-30-18

Southern Wisconsin’s flooding woes might get worse before they get significantly better with heavy rainfall forecast for Labor Day weekend.

The National Weather Service predicts 1 to 1.5 inches north of Madison, 1.5 to 2 inches in the Madison area, and 2 to 3 inches southwest of Madison from Friday night through Sunday (see accompanying picture), with more chances for showers and storms into the middle of next week.

That much rain would extend and perhaps worsen the region’s horrific flooding that started with torrential rains that fell mostly in Dane County Aug. 20 and then rounds of record rainfall north and west of Madison earlier this week, prompting Gov. Scott Walker to declare a statewide emergency.

Read our full flooding coverage here.

Flooding continues in Dane County, in counties north of Madison that include Sauk, Columbia, Marquette and Green Lake, and in the Coulee Region around La Crosse in western Wisconsin, with river flooding expected to continue into the weekend.

The Weather Service extended the flood warning for Madison centered on where the Yahara River cuts through the Isthmus connecting Lake Mendota and Lake Monona through 4:30 p.m. Thursday. Numerous roads have water on them or are closed in that area.

The Baraboo River, which is expected to crest Friday morning in La Valle, will be about 2 feet above the previous record crest of 23.2 feet set in June 2008, the Weather Service said.

The Wisconsin River at Portage is expected to rise to near 17.3 feet by Thursday evening, slightly above the flood stage of 17 feet, then fall below flood stage by late Friday morning.

The Crawfish River at Milford in Jefferson County is expected to hit 8.3 feet on Tuesday morning, above the flood stage of 7 feet.

The good news is that Thursday will be a dry day, in advance of the next rounds of storms, with chances Friday through Wednesday. The Weather Service said there is a marginal risk for severe weather for much of southern Wisconsin on Friday and again on Saturday for along the Wisconsin/Illinois border, with damaging winds, large hail and heavy rainfall the main potential hazards.

In Madison on Thursday, look for partly sunny skies, a high near 72 and calm wind becoming southeast winds around 5 miles per hour in the afternoon.

After an overnight low around 58, Friday features a 50 percent chance for showers and storms, mainly from 8 a.m. to 1 p.m., with mostly cloudy skies, a high near 76 and south winds at 5 to 15 mph.

The Weather Service said the chance for showers and storms is 80 percent overnight Friday into Saturday, with possible rain totals of a half to three-quarters of an inch as the low falls to around 67.

The chance for showers and storms is 30 percent Saturday, with a high near 77 under mostly cloudy skies, and Saturday night, with a low around 65.

The Weather Service said chances for showers and storms is 60 percent Sunday and Sunday night, with a quarter- to half-inch possible during both periods; 50 percent Monday; 30 percent Monday night; 20 percent Tuesday; 50 percent Tuesday night; and 40 percent Wednesday.

Skies over Madison should be mostly cloudy Sunday and Labor Day, and partly sunny Tuesday and Wednesday, with highs near 77, 79, 80 and 78, and lows Sunday night through Tuesday night around 66, 67 and 65.

27 Storm Track meteorologist Branden Borremans forecasts a dry Thursday, then an isolated shower or thundershower Friday, a few showers and storms Saturday through Labor Day, an isolated shower or storm Tuesday and Wednesday, and possible showers and storms next Thursday.

Borremans said skies over Madison should be mostly sunny Thursday, mostly cloudy Friday through Monday, and partly sunny Tuesday through next Thursday, with highs near 73, 76, 80, 80, 82, 86, 87 and 86, and overnight lows around 56, 67, 64, 65, 67, 69, 69 and 63.

Wednesday’s high in Madison was 70 at 4:26 p.m., 8 degrees below the normal high and 24 degrees below the record high of 94 for Aug. 29, set in 1881, 1948 and 1953.

Wednesday’s low in Madison was 57 at 11:55 p.m., the normal low and 22 degrees above the record low of 35 for Aug. 29, set in 1965.

A trace of precipitation was recorded at the Dane County Regional Airport on Wednesday, leaving Madison’s August total at 10.4 inches, 6.39 inches above normal. Madison’s meteorological summer (June through August) precipitation total stayed at 19.19 inches, 6.46 inches above normal. The 2018 total stayed at 36.03 inches, 11.47 inches below normal.

Madison’s record precipitation for Aug. 29 is 1.78 inches in 1957.

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Online Editor for Capital Newspapers.