Alert archive / Minnesota / Flash Flood Warnings in 2020

Flash Flood Warning 18, NWS Twin Cities, MN

August 22, 2020Blue Earth County, Brown County, Nicollet County, Minnesota

NWS Twin Cities, MN issued this flash flood warning at Aug 22, 2020, 1:22 AM CDT for Blue Earth County, Brown County, Nicollet County, Minnesota. It was in force for 4 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 22, 2020, 1:22 AM CDT (06:22 UTC)
Expired
Aug 22, 2020, 5:15 AM CDT
In force
4 hr
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon
Flood severity
None

Counties Blue Earth County, MN, Brown County, MN, Nicollet County, MN

The radar

The Minneapolis radar (KMPX), 83 km from the middle of the area, began a volume at 06:23 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, 6.4 hours before the alert went out and 82 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 2020-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2353 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 2020-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 120 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
2353 J/kg
Mixed-layer CIN
-98 J/kg
Mixed-layer LCL
1265 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
120 m²/s²
0-3 km storm-relative helicity
276 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

144 
WGUS53 KMPX 220622
FFWMPX
MNC013-015-103-221015-
/O.NEW.KMPX.FF.W.0018.200822T0622Z-200822T1015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Twin Cities/Chanhassen MN
122 AM CDT Sat Aug 22 2020

The National Weather Service in the Twin Cities has issued a

* Flash Flood Warning for...
  Blue Earth County in south central Minnesota...
  Northeastern Brown County in south central Minnesota...
  Nicollet County in south central Minnesota...

* Until 515 AM CDT.

* At 122 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 3 and 5 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...
  Mankato, New Ulm, North Mankato, Lake Crystal, Eagle Lake, 
  Nicollet, Madison Lake, St. Clair, Courtland, Good Thunder, 
  Lafayette, Pemberton, Garden City, Judson, Oshawa, Skyline, 
  Searles, and Klossner.

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, urban areas, highways, streets and underpasses 
as well as other drainage areas and low lying spots.

&&

LAT...LON 4424 9377 4393 9377 4394 9408 4416 9437
      4442 9479 4446 9479 4446 9437 4431 9408
      4424 9402

FLASH FLOOD...RADAR INDICATED

$$
1 follow-up statement
568 
WGUS73 KMPX 220906
FFSMPX

Flash Flood Statement
National Weather Service Twin Cities/Chanhassen MN
406 AM CDT Sat Aug 22 2020

MNC013-015-103-221015-
/O.CON.KMPX.FF.W.0018.000000T0000Z-200822T1015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Blue Earth MN-Brown MN-Nicollet MN-
406 AM CDT Sat Aug 22 2020

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 AM CDT EARLY THIS 
MORNING FOR BLUE EARTH, NORTHEASTERN BROWN AND NICOLLET COUNTIES...

At 406 AM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 3 and 6 inches of rain have 
fallen. Flash flooding is ongoing or expected to begin shortly. The 
heaviest rain has been observed in central Blue Earth county, where 
radar estimates show over 6 inches of rain have fallen near Good 
Thunder.

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 up to 1 inch are possible.

Some locations that will experience flash flooding include...
  Mankato, New Ulm, North Mankato, Lake Crystal, Eagle Lake, 
  Nicollet, Madison Lake, St. Clair, Courtland, Good Thunder, 
  Lafayette, Pemberton, Garden City, Judson, Oshawa, Skyline, 
  Searles, and Klossner.

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, urban areas, highways, streets and underpasses 
as well as other drainage areas and low lying spots.

&&

LAT...LON 4424 9377 4393 9377 4394 9408 4416 9437
      4442 9479 4446 9479 4446 9437 4431 9408
      4424 9402

FLASH FLOOD...RADAR INDICATED

$$

MPG

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 7:00 PM CDTSpecial Weather StatementMPXChippewa60 min
Aug 21, 7:20 PM CDTSevere Thunderstorm WarningMPXChippewa, Kandiyohi, Pope, Swift55 min
Aug 21, 7:55 PM CDTSpecial Weather StatementMPXKandiyohi, Meeker, Stearns50 min
Aug 21, 8:00 PM CDTSpecial Weather StatementMPXRenville60 min
Aug 21, 8:43 PM CDTSpecial Weather StatementMPXMcLeod47 min
Aug 21, 9:07 PM CDTSpecial Weather StatementMPXCarver, Wright38 min
Aug 21, 9:37 PM CDTSpecial Weather StatementMPXAnoka, Carver, Hennepin, Ramsey, Scott53 min
Aug 21, 10:12 PM CDTSpecial Weather StatementMPXLe Sueur48 min
Aug 21, 10:27 PM CDTSpecial Weather StatementMPXRenville33 min
Aug 21, 11:19 PM CDTSpecial Weather StatementMPXSibley41 min
Aug 22, 12:13 AM CDTSpecial Weather StatementMPXNicollet3 hr
Aug 22, 1:25 AM CDTSpecial Weather StatementMPXFaribault, Freeborn, Steele, Waseca3 hr
Aug 22, 6:51 AM CDTSpecial Weather StatementMPXSherburne39 min
Aug 22, 8:47 AM CDTSpecial Weather StatementMPXMorrison43 min
Aug 22, 9:26 AM CDTSpecial Weather StatementMPXKanabec, Mille Lacs64 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.