Alert archive / Minnesota / Flash Flood Warnings in 2020

Flash Flood Warning 10, NWS Twin Cities, MN

July 25, 20204 counties in Minnesota

NWS Twin Cities, MN issued this flash flood warning at Jul 25, 2020, 8:20 PM CDT for 4 counties in Minnesota. It was in force for 6 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
Jul 25, 2020, 8:20 PM CDT (01:20 UTC)
Expired
Jul 26, 2020, 2:15 AM CDT
In force
6 hr
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon
Flood severity
None

Counties Le Sueur County, MN, Nicollet County, MN, Scott County, MN, Sibley County, MN

The radar

The Minneapolis radar (KMPX), 54 km from the middle of the area, began a volume at 01:22 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
Jul 25, 11:58 PM CDTFLASH FLOOD2 Ne Lafayette, MNWATER FLOWING OVER COUNTY ROAD 8, ABOUT ONE FOOT DEEP.

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

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 1.3 hours before the alert went out and 52 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, Minneapolis, MN at 00:00Z on 2020-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1584 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, Minneapolis, MN at 00:00Z on 2020-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 229 square meters per square second.193958Sfc1 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
1584 J/kg
Mixed-layer CIN
-30 J/kg
Mixed-layer LCL
935 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
229 m²/s²
0-3 km storm-relative helicity
363 m²/s²
Significant tornado parameter
1.5
Supercell composite
12.8

Open this sounding in Storm Lab

The text

As transmitted.

809 
WGUS53 KMPX 260120
FFWMPX
MNC079-103-139-143-260715-
/O.NEW.KMPX.FF.W.0010.200726T0120Z-200726T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Twin Cities/Chanhassen MN
820 PM CDT Sat Jul 25 2020

The National Weather Service in the Twin Cities has issued a

* Flash Flood Warning for...
  Southern Sibley County in central Minnesota...
  Southwestern Scott County in east central Minnesota...
  Northwestern Le Sueur County in south central Minnesota...
  Northeastern Nicollet County in south central Minnesota...

* Until 215 AM CDT.

* At 820 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 4 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Additional rainfall amounts of 1 to 3 inches are possible.

* Some locations that will experience flash flooding include...
  Belle Plaine, Le Sueur, Le Center, Gaylord, Winthrop, Henderson, 
  Lafayette, New Sweden, Ottawa, Rush River, Norseland, New Rome and 
  St Thomas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, country roads, farmland, and other low lying 
spots.

&&

LAT...LON 4456 9443 4462 9364 4454 9365 4439 9366
      4437 9445

FLASH FLOOD...RADAR INDICATED

$$

CTG
1 follow-up statement
504 
WGUS73 KMPX 260317
FFSMPX

Flash Flood Statement
National Weather Service Twin Cities/Chanhassen MN
1017 PM CDT Sat Jul 25 2020

MNC079-103-139-143-260715-
/O.CON.KMPX.FF.W.0010.000000T0000Z-200726T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Le Sueur MN-Nicollet MN-Scott MN-Sibley MN-
1017 PM CDT Sat Jul 25 2020

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 215 AM CDT SUNDAY FOR 
SOUTHERN SIBLEY, SOUTHWESTERN SCOTT, NORTHWESTERN LE SUEUR AND 
NORTHEASTERN NICOLLET COUNTIES...

At 1017 PM CDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Between 3 
and 7 inches of rain have fallen. Heaviest rainfall is occurring in 
western Sibley county between Winthrop and Lafayette. Flash flooding 
is ongoing or expected to begin shortly.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Doppler radar and automated gauges.

IMPACT...Life-threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Additional rainfall amounts of 1 to 3 inches are possible.

Some locations that will experience flash flooding include...
  Belle Plaine, Le Sueur, Le Center, Gaylord, Winthrop, Henderson, 
  Lafayette, New Sweden, Ottawa, Rush River, Norseland, New Rome and 
  St Thomas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, country roads, farmland, and other low lying 
spots.

&&

LAT...LON 4456 9443 4462 9364 4454 9365 4439 9366
      4437 9445

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

CTG

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 25, 7:08 PM CDTSpecial Weather StatementMPXNicollet52 min
Jul 25, 7:20 PM CDTTornado WarningMPXNicollet, Sibley25 min
Jul 25, 8:15 PM CDTSpecial Weather StatementMPXLe Sueur, Nicollet, Sibley2 hr
Jul 25, 8:54 PM CDTFlash Flood WarningMPXBrown, Nicollet, Renville, Sibley8 hr
Jul 25, 9:18 PM CDTFlash Flood WatchMPXBlue Earth, Brown, Dakota, Goodhue, Le Sueur, Nicollet and 5 more12 hr
Jul 25, 9:34 PM CDTFlash Flood WarningMPXBlue Earth, Le Sueur, Nicollet, Rice6 hr
Jul 26, 2:22 AM CDTSpecial Weather StatementMPXRenville38 min
Jul 26, 2:24 AM CDTFlash Flood WarningMPXLe Sueur, Nicollet, Scott, Sibley5 hr
Jul 26, 2:26 AM CDTSpecial Weather StatementMPXDouglas, Pope, Stevens34 min
Jul 26, 2:44 AM CDTSpecial Weather StatementMPXLac qui Parle, Swift31 min
Jul 26, 3:01 AM CDTSpecial Weather StatementMPXDouglas, Pope, Todd44 min
Jul 26, 3:10 AM CDTFlash Flood WarningMPXBlue Earth, Le Sueur, Nicollet, Rice, Waseca5 hr
Jul 26, 3:18 AM CDTSpecial Weather StatementMPXChippewa, Lac qui Parle, Swift27 min
Jul 26, 3:45 AM CDTSpecial Weather StatementMPXTodd30 min
Jul 26, 4:30 AM CDTSpecial Weather StatementMPXBenton, Stearns30 min
Jul 26, 4:57 AM CDTFlash Flood WarningMPXBrown, Nicollet, Redwood, Renville, Sibley3 hr
Jul 26, 8:04 AM CDTAreal Flood WarningMPXBlue Earth, Brown, Le Sueur, Nicollet, Redwood, Renville and 2 more9 hr

Nearby

Flash Flood Warnings in Minnesota, 2020Every flash flood warning in 2020

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.