Metro Detroit weather: Flash flood watch in effect Wednesday night, Thursday morning

Storms expected early Thursday morning in SE Michigan

DETROIT – All of Metro Detroit is under a flash flood watch Wednesday night into Thursday morning.

Lenawee, Livingston, Macomb, Monroe, Oakland, Washtenaw and Wayne counties are all under the watch until 10 a.m. Thursday.

UPDATE: The flash flood watch has ended early Thursday morning, as of 8:50 a.m., as storms largely broke apart before reaching the Metro Detroit region.

Flash flood watch -- July 28-29, 2021 (WDIV)

The National Weather Service said 1 to 3 inches of rain will be possible. A flash flood watch means that conditions may develop that lead to flash flooding.

The Great Lakes Water Authority released the following statement Wednesday afternoon:

“GLWA is asking residents to be on high alert and be prepared, especially those in in low lying areas and those who have previously received flooding. The National Oceanic and Atmospheric Administration (NOAA) is predicting severe storms for early tomorrow morning and with the ground still damp from recent storms, less water will be absorbed into the ground and more run-off can be generated. Please see their forecast here.

“The regional system is prepared and working as designed. However, due to the large volumes of rain received recently, the collection system is partially full and GLWA operations is in the process of draining the system through its treatment facilities to bring levels down. In anticipation of the severe weather, GLWA has staffed accordingly, including at the Conners Creek and Freud Pumps Stations. Radar prediction per National Weather Service is 0.50 to 1.00 inches with potential to exceed 2 inches in 6 hours.”

Local forecast

Showers/storms overnight/early Thursday

  • Storm Prediction Center has increased the severe threat, we are now under a slight risk for severe weather (level 2 of 5 on their scale).
  • Timing: Looks to move in around 4 a.m., should be gone by 8 a.m., moving northwest to southeast.
  • Biggest severe threat for us will be damaging winds. Hail is also possible, as is flooding.
  • Note: While we are under the gun here, the worst of the storms should be to our west in the Grand Rapids/Kalamazoo area.
We’re gearing up for another round of storms, but they may hold off completely during the day today. It’s late tonight and overnight that brings storm and flood concerns to southeast lower Michigan and southern Ontario.

Few showers possible later Thursday

  • After the morning storms, more dry time is expected in the afternoon.
  • Then later in the day a few instability showers are possible. These shouldn’t be severe.

Weekend rain chances

  • Looks like the rain should stay just to our north Saturday, but overnight and Sunday a few showers are expected.
  • Can’t rule out storms during the overnight period.

Other weather headlines

Heaviest rain in Detroit history

  • Saturday is the anniversary of the heaviest rain in Detroit’s history.
  • 4.74 inches fell on July 31, 1925

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