Alert archive / Minnesota / Flash Flood Warnings in 2021

Flash Flood Warning 5, NWS Twin Cities, MN

August 28, 2021Redwood County, Minnesota

NWS Twin Cities, MN issued this flash flood warning at Aug 28, 2021, 9:02 PM CDT for Redwood County, Minnesota. It was in force for 6 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 28, 2021, 9:02 PM CDT (02:02 UTC)
Expired: Aug 29, 2021, 3:15 AM CDT
In force: 6 hr
Issued by: NWS Twin Cities, MN
Area: Storm-based polygon
Flood severity: None

County Redwood County, MN

The radar

The Sioux Falls radar (KFSD), 128 km from the middle of the area, began a volume at 02:03 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

Minneapolis, MN (KMPX), launched 00:00Z, 2.0 hours before the alert went out and 160 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1990 J/kg
Mixed-layer CIN: -120 J/kg
Mixed-layer LCL: 977 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 252 m²/s²
0-3 km storm-relative helicity: 227 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 5.0

Open this sounding in Storm Lab

The text

As transmitted.

660 
WGUS53 KMPX 290202
FFWMPX
MNC127-290815-
/O.NEW.KMPX.FF.W.0005.210829T0202Z-210829T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Twin Cities/Chanhassen MN
902 PM CDT Sat Aug 28 2021

The National Weather Service in the Twin Cities has issued a

* Flash Flood Warning for...
  Southwestern Redwood County in southwestern Minnesota...

* Until 315 AM CDT Sunday.

* At 902 PM CDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  2 and 3 inches of rain have fallen. Additional rainfall amounts of 
  1 to 2 inches are possible in the warned area. Flash flooding is 
  ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar and automated gauges.

  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...
  Walnut Grove, Lamberton and Revere.

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 4434 9559 4436 9552 4429 9537 4424 9525
      4420 9524 4420 9559

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

JRB

The office that day

Everything else NWS Twin Cities, MN issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 28, 7:13 PM CDT	Severe Thunderstorm Warning	MPX	Blue Earth, Le Sueur, Nicollet, Rice, Sibley	32 min
Aug 28, 7:40 PM CDT	Severe Thunderstorm Warning	MPX	Brown, Redwood	23 min
Aug 28, 7:41 PM CDT	Special Weather Statement	MPX	Blue Earth, Le Sueur, Rice, Scott	34 min
Aug 28, 8:07 PM CDT	Special Weather Statement	MPX	Rice	23 min
Aug 28, 8:17 PM CDT	Special Weather Statement	MPX	Redwood	28 min
Aug 28, 8:26 PM CDT	Special Weather Statement	MPX	Dakota, Goodhue	34 min
Aug 28, 8:57 PM CDT	Special Weather Statement	MPX	Goodhue	33 min
Aug 28, 8:59 PM CDT	Special Weather Statement	MPX	Redwood	31 min
Aug 28, 9:29 PM CDT	Special Weather Statement	MPX	Brown	31 min
Aug 28, 10:02 PM CDT	Special Weather Statement	MPX	Brown	43 min
Aug 28, 10:15 PM CDT	Tornado Warning	MPX	Brown	30 min
Aug 28, 10:52 PM CDT	Special Weather Statement	MPX	Nicollet	53 min
Aug 28, 11:28 PM CDT	Special Weather Statement	MPX	Le Sueur	47 min
Aug 29, 12:12 AM CDT	Special Weather Statement	MPX	Hennepin, Ramsey	93 min

Nearby

Flash Flood Warnings in Minnesota, 2021 Every 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.