The second round of adverse weather on the 17th started off as a large hail and damaging wind event in Sauk County, but quickly changed to a heavy rain and flash flooding event as individual cells became more numerous and clusters moved east/southeast. Training echos were common which led to flash flooding.  Damaging straight-line winds toppled large trees in Sauk and Columbia Counties while hail up to 1.00 inch in diameter also fell. However, from then on the storms became prolific rain-producers:  Watertown (Jefferson Co.) had 2.52 inches of rain in 1.5 hours, Grafton (Ozaukee Co.) had 1.75 inches in one hour.  WSR-88D Doppler radar estimated a total of 3 to 3.8 inches fell from southeast of Portage (Columbia Co.) to  the Watertown area from 1800 to 2030CST on the 17th, and 2 to 3 inches east into northern Milwaukee County.  About 2000 customers in southeast Wisconsin lost electrical power due to either downed power lines or lightning strikes.Throughout the areas that experienced flash flooding it was noted that water levels rose to 1 to 3 feet over many roads (urban and rural) leading to numerous reports of gravel shoulder washouts, blocked roads, stranded/damaged vehicles, flooded basements, and clogged sewers. In Brown Deer (Milwaukee Co.) water was up to 4 feet deep on some roads and there were reports of mudslides. Fortunately, there were no injuries or deaths, possibly due to timely warnings.For the calendar day of May 17th, Milwaukee Mitchell Field (Milwaukee Co.) picked up 1.70 inches of rain, breaking the old record of 1.20 set back in 1889.  Madison's Truax Field (Dane Co.) set a new daily record of 2.58 inches.   On the weather map the Colorado low had moved to eastern Nebraska by the end of the 17th while the west-east frontal boundary had moved north to the Wisconsin/Illinois border.  Southern Wisconsin during the time of the flooding had northeast winds and temperatures around 60.

Flash Flood in COLUMBIA, WISCONSIN
From 17-MAY-00 20:15:00 to 18-MAY-00 01:00:00 (CST)
Location: SOUTH PORTION
Property damage: 50K
Reported by: AMATEUR RADIO

Flash Flood in OZAUKEE, WISCONSIN
From 17-MAY-00 20:15:00 to 18-MAY-00 01:00:00 (CST)
Location: MEQUON
Property damage: 75K
Reported by: AMATEUR RADIO

Hail in KENOSHA, WISCONSIN
From 17-MAY-00 20:10:00 to 17-MAY-00 20:10:00 (CST)
Location: SOMERS
Magnitude: 1.00 
Reported by: LAW ENFORCEMENT

Flash Flood in DODGE, WISCONSIN
From 17-MAY-00 20:15:00 to 18-MAY-00 01:00:00 (CST)
Location: JUNEAU
Property damage: 50K
Reported by: AMATEUR RADIO

Hail in DODGE, WISCONSIN
From 17-MAY-00 19:10:00 to 17-MAY-00 19:10:00 (CST)
Location: RANDOLPH
Magnitude: 0.75 
Reported by: NEWSPAPER

Flash Flood in JEFFERSON, WISCONSIN
From 17-MAY-00 20:15:00 to 18-MAY-00 01:00:00 (CST)
Location: WATERTOWN
Property damage: 25K
Reported by: AMATEUR RADIO

Thunderstorm Wind in COLUMBIA, WISCONSIN
From 17-MAY-00 18:35:00 to 17-MAY-00 18:45:00 (CST)
Location: PORTAGE
Property damage: 1K
Reported by: LAW ENFORCEMENT

Flash Flood in WASHINGTON, WISCONSIN
From 17-MAY-00 20:15:00 to 18-MAY-00 01:00:00 (CST)
Location: SOUTH PORTION
Property damage: 75K
Reported by: AMATEUR RADIO

Flash Flood in WAUKESHA, WISCONSIN
From 17-MAY-00 20:15:00 to 18-MAY-00 01:00:00 (CST)
Location: MAPLETON
Property damage: 50K
Reported by: AMATEUR RADIO

Flash Flood in MILWAUKEE, WISCONSIN
From 17-MAY-00 20:15:00 to 18-MAY-00 01:00:00 (CST)
Location: NORTH PORTION
Property damage: 200K
Reported by: AMATEUR RADIO

Flash Flood in DODGE, WISCONSIN
From 17-MAY-00 19:00:00 to 17-MAY-00 20:00:00 (CST)
Location: DANVILLE
Property damage: 20K
Reported by: LAW ENFORCEMENT

Flash Flood in SAUK, WISCONSIN
From 17-MAY-00 18:15:00 to 17-MAY-00 19:30:00 (CST)
Location: BARABOO
Property damage: 10K
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in SAUK, WISCONSIN
From 17-MAY-00 18:22:00 to 17-MAY-00 18:22:00 (CST)
Location: BARABOO
Magnitude: 52 E
Property damage: 2K
Reported by: AMATEUR RADIO