Alert archive / Michigan / Flash Flood Warnings in 2021

Flash Flood Warning 7, NWS Detroit, MI

August 24, 2021Wayne County, Michigan

NWS Detroit, MI issued this flash flood warning at Aug 24, 2021, 9:57 PM EDT for Wayne County, Michigan. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 24, 2021, 9:57 PM EDT (01:57 UTC)
Expired
Aug 25, 2021, 12:19 AM EDT
In force
2 hr
Issued by
NWS Detroit, MI
Area
Storm-based polygon
Flood severity
None

County Wayne County, MI

The radar

The Detroit radar (KDTX), 69 km from the middle of the area, began a volume at 02:01 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Detroit, MI (KDTX), launched 00:00Z, 2.0 hours before the alert went out and 70 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Detroit, MI at 00:00Z on 2021-08-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3040 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Detroit, MI at 00:00Z on 2021-08-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
3040 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
1099 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
25 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

412 
WGUS53 KDTX 250157
FFWDTX
MIC163-250500-
/O.NEW.KDTX.FF.W.0007.210825T0157Z-210825T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Detroit/Pontiac MI
957 PM EDT Tue Aug 24 2021

The National Weather Service in Detroit/Pontiac has issued a

* Flash Flood Warning for...
  South Central Wayne County in southeastern Michigan...

* Until 100 AM EDT.

* At 957 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 4 inches of rain 
  have fallen. The expected rainfall rate is 1 to 2 inches in 1 
  hour. Additional rainfall amounts up to 1 inch are possible in the 
  warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Flat Rock, Trenton, Grosse Ile, Woodhaven, Riverview, Gibraltar 
  and Rockwood.

This includes the following highways...
I-75 between mile markers 28 and 33.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4208 8327 4212 8328 4218 8321 4215 8313
      4213 8312 4209 8313 4209 8315 4209 8319

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

Behnke
1 follow-up statement
899 
WGUS73 KDTX 250419
FFSDTX

Flash Flood Statement
National Weather Service Detroit/Pontiac MI
1219 AM EDT Wed Aug 25 2021

MIC163-250429-
/O.CAN.KDTX.FF.W.0007.000000T0000Z-210825T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Wayne MI-
1219 AM EDT Wed Aug 25 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTH CENTRAL WAYNE COUNTY...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 4208 8327 4212 8328 4218 8321 4215 8313
      4213 8312 4209 8313 4209 8315 4209 8319

$$

SC

The office that day

Everything else NWS Detroit, MI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 24, 8:02 PM EDTSevere Thunderstorm WarningDTXLapeer30 min
Aug 24, 8:05 PM EDTSpecial Weather StatementDTXOakland55 min
Aug 24, 8:10 PM EDTSpecial Weather StatementDTXWayne35 min
Aug 24, 8:31 PM EDTSpecial Weather StatementDTXMacomb44 min
Aug 24, 8:36 PM EDTAreal Flood AdvisoryDTXMacomb, Oakland, Wayne2 hr
Aug 24, 9:28 PM EDTAreal Flood AdvisoryDTXMacomb92 min
Aug 24, 9:40 PM EDTSpecial Weather StatementDTXMacomb35 min
Aug 25, 3:10 AM EDTSpecial Weather StatementDTXTuscola80 min
Aug 25, 3:21 AM EDTHeat AdvisoryDTXLenawee, Livingston, Macomb, Monroe, Oakland, Washtenaw and 1 more17 hr
Aug 25, 5:43 AM EDTSpecial Marine WarningDTX26 min

Nearby

Flash Flood Warnings in Michigan, 2021Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.