A slow moving upper low over Illinois combined with a conveyor belt of humid air over Ohio supported widespread showers and thunderstorms over southern and central Ohio on the afternoon and evening of the 18th. The weather conditions supported not severe weather but heavy rain. Rain rates of 2 inches an hour or higher were observed with storms that trained, or repeated over the same areas.  Overnight the low sank further south and drier air filtered into north and eastern counties which reduced their flood risk. However, it set up a boundary with warmer and moist air from Bowling Green to Mt. Vernon where moderate to heavy rain fell during the early morning hours of the 19th.  A flood watch had been issued on the evening of the 18th through late morning on the 19th. The heaviest rainfall was measured around 3 to 4 inches in portions of Wood, Marion, Wyandot, Knox, and Morrow Counties.  Several roads were flooded with mainly minor impacts. A flash flood occurred in Upper Sandusky as US 30 eastbound lanes were closed near Upper Sandusky after flood waters washed out a culvert. There were multiple vehicles stalled in the City of Marion due to high water. The heavy rain in Wood County resulted in major flooding on the Portage River at Woodville by the 20th. The high river levels combined with high lake levels at the mouth to produce additional flooding in areas downstream that don���t typically flood.

Flood in MARION, OHIO
From 19-MAY-20 02:20:00 to 19-MAY-20 05:00:00 (EST-5)
Location: BIG IS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Two cars stalled in high water on Church Street in Marion. High water signs along route 4 in or near Marion. SR 203 flooded, east of SR4 and that it was flooding into Prospect.

Flash Flood in WYANDOT, OHIO
From 19-MAY-20 05:00:00 to 19-MAY-20 05:30:00 (EST-5)
Location: UPPER SANDUSKY ARPT
Flood cause: Heavy Rain
Property damage: 65.00K
Crop damage: 0.00K
Reported by: Department of Highways

A main thruway in Wyandot County sustained a washout due to heavy rain on the 19th. The eastbound lanes of U.S. 30 near Upper Sandusky the road closure was just east of U.S. 23 in Wyandot County. The damage was caused by a 90-inch culvert, that washed out and eroded about 20 feet under the eastbound lane to the center line. Most of the flood came as overland runoff from agricultural fields adjacent to the highway.

Flood in WOOD, OHIO
From 20-MAY-20 06:00:00 to 21-MAY-20 06:00:00 (EST-5)
Location: PEMBERVILLE
Flood cause: Heavy Rain
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Major flooding on the Portage River at Woodville. Worst flooding since 2013 in Pemberville. In hardest hit Pemberville, Water Street flooded, businesses inundated on the ground level. Bridge Street closed due to flooding. In Elmore the Portage River  swept away much of the temporary stone causeway that construction workers were using for river access to a construction site. The flood was caused by heavy rain on the 18th and 19th estimated around 2 to 4 inches primarily in the headwaters.

Flood in MORROW, OHIO
From 18-MAY-20 21:05:00 to 19-MAY-20 05:00:00 (EST-5)
Location: CHESTERVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Heavy rainfall of 1 to 3 inches over Morrow County on the evening of the 18th resulted in widespread flooding of local and state roads. Those roads include the following; SR 314 and SR 95, SR 314 and SR 229, Road 21, west of SR 314, Road 170 and SR 229, Road 20, east of 21, SR 61 and Road 25.

Flood in RICHLAND, OHIO
From 18-MAY-20 22:45:00 to 19-MAY-20 05:00:00 (EST-5)
Location: SHELBY ARPT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Rainfall of 1 to 2.5 inches on already wet ground produced widespread flooding across Richland County, particularly in the northern part of the county near Shelby. Some of the known road closures include the following; Bellville-Johnsville, Eric Road, Plymouth,  Springmill, SR-61 near Shelby, Champion Road between Hazel Brush and London West Road, London East between Fakler and Ganges Five Points, and Rome between SR603 and Ganges east, and Springfield Twp High water on OH-314 north of OH-309.

Flood in HANCOCK, OHIO
From 19-MAY-20 15:00:00 to 19-MAY-20 16:00:00 (EST-5)
Location: (FDY)FINDLAY ARPT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Water rescue for women who drove into flooded road via the Blanchard River. The Blanchard River was in minor flood stage at the time of the incident.

Flood in KNOX, OHIO
From 18-MAY-20 21:05:00 to 19-MAY-20 09:00:00 (EST-5)
Location: CENTERBURG ARPT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Rainfall amounts of 1 to 3 inches fell over Knox County between the 18th and again in the early morning hours of the 19th. High Water reported on Old Delaware Road at Tucker Road in Liberty Township. No water rescues or stalled vehicles reported in Knox County.
- Larimore Rd. near Homer Rd. (Likely near the river)
- Beckley Rd @ Bryant
- Waterford Rd. near Whitney
- Simmons Church @ Columbus Rd.
- Johnstown Rd. near Centerburg.