Alert archive / Tennessee / Flash Flood Warnings in 2021

Flash Flood Warning 39, NWS Morristown, TN

September 18, 2021Bledsoe County, Sequatchie County, Tennessee

NWS Morristown, TN issued this flash flood warning at Sep 18, 2021, 5:20 PM CDT for Bledsoe County, Sequatchie County, Tennessee. It was in force for 3 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
Sep 18, 2021, 5:20 PM CDT (22:20 UTC)
Expired
Sep 18, 2021, 8:30 PM CDT
In force
3 hr
Issued by
NWS Morristown, TN
Area
Storm-based polygon
Flood severity
None

Counties Bledsoe County, TN, Sequatchie County, TN

The radar

The Northeast Alabama radar (KHTX), 89 km from the middle of the area, began a volume at 22:23 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.

What was reported inside it

TimeReportWhereRemark
Sep 18, 6:45 PM CDTFLASH FLOOD3 Nne Dunlap, TNFLOODING ONGOING BUT STARTING TO IMPROVE.

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, 10.3 hours before the alert went out and 126 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 2021-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1085 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 2021-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
1085 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
648 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
51 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

701 
WGUS54 KMRX 182220
FFWMRX
TNC007-153-190130-
/O.NEW.KMRX.FF.W.0039.210918T2220Z-210919T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Morristown TN
520 PM CDT Sat Sep 18 2021

The National Weather Service in Morristown has issued a

* Flash Flood Warning for...
  Southwestern Bledsoe County in east Tennessee...
  Northeastern Sequatchie County in east Tennessee...

* Until 830 PM CDT.

* At 520 PM CDT, local law enforcement reported flash flooding was 
  ongoing after the heavy rain from thunderstorms earlier today. 
  Between 2 and 4 inches of rain have fallen. Additional rainfall 
  amounts up to 0.5 inches are possible in the warned area. Flash 
  flooding is already occurring and some evacuations are taking 
  place.

  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...
  Dunlap, Pikeville, Palio, Old Cumberland, Cagle and Fall Creek 
  Falls State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3534 8529 3553 8556 3554 8555 3554 8554
      3554 8553 3555 8550 3555 8546 3556 8545
      3557 8542 3565 8533 3557 8514

FLASH FLOOD...OBSERVED

$$

GC

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 18, 11:47 AM CDTAreal Flood AdvisoryMRXAnderson, Morgan, Scott118 min
Sep 18, 1:55 PM CDTAreal Flood AdvisoryMRXBledsoe, Sequatchie110 min
Sep 18, 2:17 PM CDTFlash Flood WarningMRXBledsoe, Sequatchie3 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.