Alert archive / Michigan / Flash Flood Warnings in 2021

Flash Flood Warning 5, NWS Detroit, MI

August 12, 2021Livingston County, Michigan

NWS Detroit, MI issued this flash flood warning at Aug 12, 2021, 4:33 AM EDT for Livingston County, Michigan. It was in force for 2 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 12, 2021, 4:33 AM EDT (08:33 UTC)
Expired
Aug 12, 2021, 6:43 AM EDT
In force
2 hr
Issued by
NWS Detroit, MI
Area
Storm-based polygon
Flood severity
None

County Livingston County, MI

The radar

The Detroit radar (KDTX), 33 km from the middle of the area, began a volume at 08:37 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.

What was reported inside it

TimeReportWhereRemark
Aug 12, 4:33 AM EDTFLOOD1 S Howell, MIMDOT REPORTS EB I-96 AFTER PINCKNEY ROAD IS CLOSED DUE TO FLOODING.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Detroit, MI (KDTX), launched 00:00Z, 8.6 hours before the alert went out and 36 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 2021-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 12 joules per kilogram.LCLLFCEL10008507005003002001001 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 2021-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 243 square meters per square second.19395878Sfc1 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
12 J/kg
Mixed-layer CIN
-458 J/kg
Mixed-layer LCL
1474 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
243 m²/s²
0-3 km storm-relative helicity
373 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

148 
WGUS53 KDTX 120833
FFWDTX
MIC093-121100-
/O.NEW.KDTX.FF.W.0005.210812T0833Z-210812T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Detroit/Pontiac MI
433 AM EDT Thu Aug 12 2021

The National Weather Service in Detroit/Pontiac has issued a

* Flash Flood Warning for...
  Livingston County in southeastern Michigan...

* Until 700 AM EDT.

* At 433 AM EDT, Doppler radar indicated scattered to numerous 
  thunderstorms moving across the warned area. Heavy rain has lead 
  to flooding on I-96, with road closures reported near Pickney 
  Road. Between 2 and 4 inches of rain have fallen, with additional 
  rainfall amounts of 1 to 2 inches possible in the warned area.

  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...
  Hartland, Howell, Brighton, Fowlerville, Cohoctah, Oak Grove, 
  Deerfield Township, Chilson, Tyrone Township, Conway Township and 
  Parkers Corners.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4278 8369 4251 8367 4251 8414 4278 8416

FLASH FLOOD...RADAR INDICATED

$$

MR
2 follow-up statements
928 
WGUS73 KDTX 120942
FFSDTX

Flash Flood Statement
National Weather Service Detroit/Pontiac MI
542 AM EDT Thu Aug 12 2021

MIC093-121100-
/O.CON.KDTX.FF.W.0005.000000T0000Z-210812T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Livingston MI-
542 AM EDT Thu Aug 12 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 AM EDT THIS MORNING 
FOR LIVINGSTON COUNTY...

At 542 AM EDT, Law enforcement reports ongoing flooding in and 
around Howell. Flooding is occuring on I-96, with road closures 
reported. Rainfall will gradually taper off through the mid morning 
hours, with additional rainfall amounts of less than a quarter of an 
inch expected.

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...
  Hartland, Howell, Brighton, Fowlerville, Cohoctah, Oak Grove, 
  Deerfield Township, Chilson, Tyrone Township, Conway Township and 
  Parkers Corners.

This includes the following highways...
	I-96 between mile markers 125 and 152.
	US-23 between mile markers 59 and 77.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4278 8369 4251 8367 4251 8414 4278 8416

FLASH FLOOD...RADAR INDICATED

$$

MR
260 
WGUS73 KDTX 121043
FFSDTX

Flash Flood Statement
National Weather Service Detroit/Pontiac MI
643 AM EDT Thu Aug 12 2021

MIC093-121053-
/O.CAN.KDTX.FF.W.0005.000000T0000Z-210812T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Livingston MI-
643 AM EDT Thu Aug 12 2021

...FLASH FLOOD WARNING FOR LIVINGSTON COUNTY HAS BEEN REPLACED WITH 
A FLOOD WARNING...

Rainfall has ended across the area. Therefore, the threat for flash 
flooding no longer exists. Flooding of roadways and structures 
resulting from earlier rainfall will continue through the morning 
period.

LAT...LON 4278 8369 4251 8367 4251 8414 4278 8416

$$

MR

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 10:42 PM EDTSpecial Weather StatementDTXGenesee, Lapeer, Livingston, Oakland, Shiawassee63 min
Aug 11, 11:00 PM EDTSpecial Weather StatementDTXLenawee, Washtenaw60 min
Aug 11, 11:34 PM EDTSpecial Weather StatementDTXMacomb, Monroe, Saint Clair, Wayne56 min
Aug 12, 12:47 AM EDTSpecial Weather StatementDTXTuscola43 min
Aug 12, 1:14 AM EDTSpecial Weather StatementDTXGenesee, Shiawassee46 min
Aug 12, 2:04 AM EDTAreal Flood AdvisoryDTXLivingston2 hr
Aug 12, 2:36 AM EDTSpecial Weather StatementDTXWayne54 min
Aug 12, 3:08 AM EDTAreal Flood AdvisoryDTXWayne4 hr
Aug 12, 5:18 AM EDTAreal Flood AdvisoryDTXMacomb, Oakland3 hr
Aug 12, 5:41 AM EDTFlash Flood WarningDTXMacomb, Oakland, Wayne3 hr
Aug 12, 6:31 AM EDTSevere Thunderstorm WarningDTXLenawee, Livingston, Monroe, Washtenaw59 min
Aug 12, 6:43 AM EDTAreal Flood WarningDTXLivingston2 hr
Aug 12, 7:09 AM EDTSevere Thunderstorm WarningDTXMacomb, Monroe, Oakland, Wayne45 min
Aug 12, 7:18 AM EDTSpecial Weather StatementDTXMonroe42 min
Aug 12, 7:27 AM EDTSpecial Marine WarningDTX34 min
Aug 12, 7:35 AM EDTRiver Flood WarningDTXLivingston18 days
Aug 12, 8:42 AM EDTAreal Flood AdvisoryDTXMacomb, Oakland, Wayne3 hr
Aug 12, 11:53 AM EDTRiver Flood WarningDTXMacomb7 hr
Aug 12, 6:08 PM EDTRiver Flood WarningDTXWayne15 hr

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.