Alert archive / Tennessee / Flash Flood Warnings in 2021

Flash Flood Warning 34, NWS Morristown, TN

August 25, 2021Knox County, Loudon County, Tennessee

NWS Morristown, TN issued this flash flood warning at Aug 25, 2021, 4:49 PM EDT for Knox County, Loudon County, Tennessee. It was in force for 3 hr. 3 reports 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 25, 2021, 4:49 PM EDT (20:49 UTC)
Expired
Aug 25, 2021, 7:50 PM EDT
In force
3 hr
Issued by
NWS Morristown, TN
Area
Storm-based polygon
Flood severity
None

Counties Knox County, TN, Loudon County, TN

The radar

The Knoxville radar (KMRX), 73 km from the middle of the area, began a volume at 20:51 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 25, 4:55 PM EDTFLASH FLOOD4 Sse Karns, TNHIGH WATER ON NORTH PETERS ROAD IN KNOXVILLE.
Aug 25, 5:09 PM EDTHEAVY RAIN 22 Ne Knoxville, TN2 INCHES OF RAIN IN 45 MINUTES AT WBIR STUDIOS IN NORTH KNOXVILLE.
Aug 25, 5:15 PM EDTFLASH FLOOD1 S Karns, TNHIGH WATER WITH STALLED VEHICLES ON MIDDLEBROOK PIKE.

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

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 8.8 hours before the alert went out and 223 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, Nashville Metro, TN at 12:00Z on 2021-08-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 729 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Nashville Metro, TN at 12:00Z on 2021-08-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -6 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
729 J/kg
Mixed-layer CIN
-70 J/kg
Mixed-layer LCL
1368 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
-6 m²/s²
0-3 km storm-relative helicity
-27 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

464 
WGUS54 KMRX 252049
FFWMRX
TNC093-105-260000-
/O.NEW.KMRX.FF.W.0034.210825T2049Z-210826T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Morristown TN
449 PM EDT Wed Aug 25 2021

The National Weather Service in Morristown has issued a

* Flash Flood Warning for...
  Knox County in east Tennessee...
  Northeastern Loudon County in east Tennessee...

* Until 800 PM EDT.

* At 449 PM EDT, local law enforcement reported thunderstorms 
  producing heavy rain across the warned area. Flash flooding is 
  already occurring.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Law enforcement reported.

  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...
  Knoxville, Oak Ridge, Lenoir City, Alcoa, Loudon, Farragut, 
  Louisville, Rockford, Halls, Bearden, Powell, Karns, Lake Forest, 
  Maloneyville, Seymour, Kimberlin Heights, Mascot and Tellico 
  Village.

Flash Flooding is occurring across Western Knoxville avoid flooded 
roads on your evening commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3592 8425 3594 8427 3593 8424 3599 8419
      3602 8408 3607 8409 3617 8390 3595 8368
      3584 8385 3588 8400 3583 8406 3585 8414
      3580 8414 3580 8417 3577 8418 3575 8415
      3572 8428 3581 8438 3589 8433 3588 8428

FLASH FLOOD...OBSERVED

$$

19
3 follow-up statements
248 
WGUS74 KMRX 252116
FFSMRX

Flash Flood Statement
National Weather Service Morristown TN
516 PM EDT Wed Aug 25 2021

TNC093-105-260000-
/O.CON.KMRX.FF.W.0034.000000T0000Z-210826T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Knox TN-Loudon TN-
516 PM EDT Wed Aug 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM EDT THIS EVENING 
FOR KNOX AND NORTHEASTERN LOUDON COUNTIES...

At 516 PM EDT, local law enforcement reported thunderstorms 
producing heavy rain across the warned area. Between 1 and 3 inches 
of rain have fallen. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Law enforcement reported.

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...
  Knoxville, Oak Ridge, Lenoir City, Alcoa, Loudon, Farragut, 
  Louisville, Rockford, Halls, Bearden, Powell, Karns, Lake Forest, 
  Maloneyville, Seymour, Kimberlin Heights, Mascot and Tellico 
  Village.

Flash Flooding is occurring across Western and Northern Knoxville...
 Avoid flooded roads on your evening commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3592 8425 3594 8427 3593 8424 3599 8419
      3602 8408 3607 8409 3617 8390 3595 8368
      3584 8385 3588 8400 3583 8406 3585 8414
      3580 8414 3580 8417 3577 8418 3575 8415
      3572 8428 3581 8438 3589 8433 3588 8428

FLASH FLOOD...OBSERVED

$$

19
068 
WGUS74 KMRX 252159
FFSMRX

Flash Flood Statement
National Weather Service Morristown TN
559 PM EDT Wed Aug 25 2021

TNC093-105-260000-
/O.CON.KMRX.FF.W.0034.000000T0000Z-210826T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Knox TN-Loudon TN-
559 PM EDT Wed Aug 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM EDT THIS EVENING 
FOR KNOX AND NORTHEASTERN LOUDON COUNTIES...

At 559 PM EDT, local law enforcement reported flash flooding in 
parts of Knoxville. Between 1 and 3 inches of rain have fallen. 
Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Law enforcement reported.

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...
  Knoxville, Oak Ridge, Lenoir City, Alcoa, Loudon, Farragut, 
  Louisville, Rockford, Halls, Bearden, Powell, Karns, Lake Forest, 
  Maloneyville, Seymour, Kimberlin Heights, Mascot and Tellico 
  Village.

Even though the rain is ending flood waters will take some time to 
recede across parts of Knoxville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3592 8425 3594 8427 3593 8424 3599 8419
      3602 8408 3607 8409 3617 8390 3595 8368
      3584 8385 3588 8400 3583 8406 3585 8414
      3580 8414 3580 8417 3577 8418 3575 8415
      3572 8428 3581 8438 3589 8433 3588 8428

FLASH FLOOD...OBSERVED

$$

19
074 
WGUS74 KMRX 252350
FFSMRX

Flash Flood Statement
National Weather Service Morristown TN
750 PM EDT Wed Aug 25 2021

TNC093-105-260000-
/O.CAN.KMRX.FF.W.0034.000000T0000Z-210826T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Knox TN-Loudon TN-
750 PM EDT Wed Aug 25 2021

...FLASH FLOOD WARNING FOR KNOX AND NORTHEASTERN LOUDON COUNTIES HAS 
BEEN REPLACED WITH A FLOOD ADVISORY...

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

LAT...LON 3592 8425 3594 8427 3593 8424 3599 8419
      3602 8408 3607 8409 3617 8390 3595 8368
      3584 8385 3588 8400 3583 8406 3585 8414
      3580 8414 3580 8417 3577 8418 3575 8415
      3572 8428 3581 8438 3589 8433 3588 8428

$$

19

The office that day

Everything else NWS Morristown, TN issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 25, 2:18 PM EDTSpecial Weather StatementMRXCarter42 min
Aug 25, 2:52 PM EDTSpecial Weather StatementMRXMorgan38 min
Aug 25, 3:20 PM EDTSpecial Weather StatementMRXSevier40 min
Aug 25, 3:46 PM EDTSpecial Weather StatementMRXSevier44 min
Aug 25, 4:02 PM EDTAreal Flood AdvisoryMRXMorgan3 hr
Aug 25, 4:02 PM EDTSpecial Weather StatementMRXKnox43 min
Aug 25, 4:07 PM EDTSpecial Weather StatementMRXJohnson38 min
Aug 25, 4:13 PM EDTSevere Thunderstorm WarningMRXAnderson, Knox47 min
Aug 25, 4:20 PM EDTAreal Flood AdvisoryMRXJohnson3 hr
Aug 25, 4:21 PM EDTSpecial Weather StatementMRXKnox24 min
Aug 25, 4:32 PM EDTAreal Flood AdvisoryMRXKnox, Loudon22 min
Aug 25, 5:01 PM EDTSpecial Weather StatementMRXGrainger44 min
Aug 25, 5:08 PM EDTSpecial Weather StatementMRXKnox52 min
Aug 25, 5:22 PM EDTAreal Flood AdvisoryMRXBledsoe3 hr
Aug 25, 5:26 PM EDTAreal Flood AdvisoryMRXBlount3 hr
Aug 25, 5:31 PM EDTAreal Flood AdvisoryMRXSullivan3 hr
Aug 25, 5:38 PM EDTAreal Flood AdvisoryMRXGrainger, Jefferson, Knox, Sevier, Union3 hr
Aug 25, 5:49 PM EDTSpecial Weather StatementMRXGrainger41 min
Aug 25, 5:53 PM EDTSpecial Weather StatementMRXSullivan52 min
Aug 25, 6:23 PM EDTSevere Thunderstorm WarningMRXGreene, Hamblen37 min
Aug 25, 6:27 PM EDTSpecial Weather StatementMRXGreene33 min
Aug 25, 6:30 PM EDTSpecial Weather StatementMRXSullivan45 min
Aug 25, 6:33 PM EDTSpecial Weather StatementMRXMcMinn27 min
Aug 25, 6:38 PM EDTSpecial Weather StatementMRXUnion37 min
Aug 25, 6:41 PM EDTSevere Thunderstorm WarningMRXGreene34 min
Aug 25, 6:54 PM EDTAreal Flood AdvisoryMRXGreene, Hamblen, Hawkins3 hr
Aug 25, 6:54 PM EDTSpecial Weather StatementMRXWashington51 min
Aug 25, 7:01 PM EDTAreal Flood AdvisoryMRXMcMinn3 hr
Aug 25, 7:03 PM EDTAreal Flood AdvisoryMRXClaiborne, Grainger, Union3 hr
Aug 25, 7:05 PM EDTAreal Flood AdvisoryMRXSullivan3 hr
Aug 25, 7:29 PM EDTSpecial Weather StatementMRXHawkins46 min
Aug 25, 7:50 PM EDTAreal Flood AdvisoryMRXKnox, Loudon70 min

Nearby

Flash Flood Warnings in Tennessee, 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.