Alert archive / Tennessee / Flash Flood Warnings in 2021

Flash Flood Warning 40, NWS Morristown, TN

September 19, 2021Hamilton County, Marion County, Sequatchie County, Tennessee

NWS Morristown, TN issued this flash flood warning at Sep 19, 2021, 5:33 PM EDT for Hamilton County, Marion County, Sequatchie County, Tennessee. 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
Sep 19, 2021, 5:33 PM EDT (21:33 UTC)
Expired
Sep 19, 2021, 11:15 PM EDT
In force
6 hr
Issued by
NWS Morristown, TN
Area
Storm-based polygon
Flood severity
None

Counties Hamilton County, TN, Marion County, TN, Sequatchie County, TN

The radar

The Northeast Alabama radar (KHTX), 66 km from the middle of the area, began a volume at 21:35 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

Nashville Metro, TN (KBNA), launched 12:00Z, 9.6 hours before the alert went out and 139 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 2021-09-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 92 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, Nashville Metro, TN at 12:00Z on 2021-09-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 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
92 J/kg
Mixed-layer CIN
-60 J/kg
Mixed-layer LCL
895 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
11 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

895 
WGUS54 KMRX 192133
FFWMRX
TNC065-115-153-200130-
/O.NEW.KMRX.FF.W.0040.210919T2133Z-210920T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Morristown TN
533 PM EDT Sun Sep 19 2021

The National Weather Service in Morristown has issued a

* Flash Flood Warning for...
  Southwestern Hamilton County in east Tennessee...
  Eastern Marion County in east Tennessee...
  Southern Sequatchie County in east Tennessee...

* Until 930 PM EDT /830 PM CDT/.

* At 533 PM EDT /433 PM CDT/, Doppler radar indicated thunderstorms 
  producing heavy rain across the warned area. This also comes after 
  recent heavy rainfall that has led to saturated grounds. Between 
  0.5 and 1 inch of rain has fallen. The expected rainfall rate is 
  0.5 to 1 inch in 1 hour. 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.

  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...
  Chattanooga, Signal Mountain, Walden, Whitwell, Fairmount, Red 
  Bank, Powells Crossroads, Lone Oak, Cartwright, Martin Springs, 
  Hicks Gap State Park, Chimneys State Park, Falling Water, North 
  Chickamauga Creek Gorge, Griffith Creek, Lookout Mountain and East 
  Ridge.

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3532 8556 3534 8554 3534 8553 3536 8551
      3537 8551 3538 8550 3526 8528 3499 8527
      3498 8547 3531 8562

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...0.5-1 INCH IN 1 HOUR

$$

BW
2 follow-up statements
680 
WGUS54 KMRX 200114
FFWMRX
TNC065-115-153-200315-
/O.EXT.KMRX.FF.W.0040.000000T0000Z-210920T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Morristown TN
914 PM EDT Sun Sep 19 2021

The National Weather Service in Morristown has extended the

* Flash Flood Warning for...
  Southwestern Hamilton County in east Tennessee...
  Eastern Marion County in east Tennessee...
  Southern Sequatchie County in east Tennessee...

* Until 1115 PM EDT /1015 PM CDT/.

* At 914 PM EDT /814 PM CDT/, Doppler radar indicated thunderstorms 
  producing heavy rain across the warned area. This comes after 
  heavy rainfall and flooding from yesterday. Between 0.5 and 1.5 
  inches of rain have fallen with additional light amounts expected. 
  Flash flooding is ongoing or expected to begin shortly due to 
  runoff from this evening's rainfall and an already saturated 
  ground.

  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...
  Chattanooga, Signal Mountain, Walden, Whitwell, Fairmount, Red 
  Bank, Powells Crossroads, Lone Oak, Cartwright, Martin Springs, 
  Hicks Gap State Park, Chimneys State Park, Falling Water, North 
  Chickamauga Creek Gorge, Griffith Creek, Lookout Mountain and East 
  Ridge.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3532 8556 3534 8554 3534 8553 3536 8551
      3537 8551 3538 8550 3526 8528 3499 8527
      3498 8547 3531 8562

FLASH FLOOD...RADAR INDICATED

$$

BW
389 
WGUS74 KMRX 200320
FFSMRX

Flash Flood Statement
National Weather Service Morristown TN
1020 PM CDT Sun Sep 19 2021

TNC115-153-200330-
/O.EXP.KMRX.FF.W.0040.000000T0000Z-210920T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Marion TN-Sequatchie TN-
1020 PM CDT Sun Sep 19 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTHWESTERN HAMILTON, 
EASTERN MARION AND SOUTHERN SEQUATCHIE COUNTIES...

A Flood Warning remains in effect for southwestern Hamilton County 
until 900 AM EDT.

A Flash Flood Watch remains in effect until 700 PM CDT Monday for A 
portion of east Tennessee.

LAT...LON 3532 8556 3534 8554 3534 8553 3536 8551
      3537 8551 3538 8550 3526 8528 3499 8527
      3498 8547 3531 8562

$$

BW

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 19, 3:12 AM EDTFlash Flood WatchMRXBledsoe, Bradley, Hamilton, Marion, Meigs, Rhea and 1 more47 hr
Sep 19, 10:19 AM EDTAreal Flood AdvisoryMRXHamilton, Marion, Sequatchie3 hr
Sep 19, 3:36 PM EDTSpecial Weather StatementMRXSevier39 min
Sep 19, 3:59 PM EDTSpecial Weather StatementMRXHamblen, Jefferson46 min
Sep 19, 4:19 PM EDTAreal Flood AdvisoryMRXHamilton, Marion, Sequatchie3 hr
Sep 19, 7:14 PM EDTFlash Flood WarningMRXHamilton4 hr

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