Alert archive / Tennessee / Areal Flood Advisories in 2021

Areal Flood Advisory 152, NWS Nashville, TN

September 20, 20217 counties in Tennessee

NWS Nashville, TN issued this areal flood advisory at Sep 20, 2021, 8:29 AM CDT for 7 counties in Tennessee. It was in force for 2 hr.

The area

The counties it named.

The facts

Issued
Sep 20, 2021, 8:29 AM CDT (13:29 UTC)
Expired
Sep 20, 2021, 10:30 AM CDT
In force
2 hr
Issued by
NWS Nashville, TN
Area
Storm-based polygon

Counties Cheatham County, TN, Davidson County, TN, Hickman County, TN, Lewis County, TN, Marshall County, TN, Maury County, TN, Williamson County, TN

The radar

The Nashville radar (KOHX), 67 km from the middle of the area, began a volume at 13:31 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

Birmingham, AL (KBMX), launched 12:00Z, 1.5 hours before the alert went out and 295 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, Birmingham, AL at 12:00Z on 2021-09-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 513 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, Birmingham, AL at 12:00Z on 2021-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 52 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
513 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
460 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
52 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Nashville, TN wrote its last area forecast discussion before this areal flood advisory went out at Sep 20, 6:05 AM CDT, 2 hours 24 minutes earlier.

Area forecast discussion, Sep 20, 6:05 AM CDT, 2 hours 24 minutes before
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Hazardous weather outlook, Sep 20, 2:38 AM CDT, 5 hours 51 minutes before
Hazardous Weather Outlook
National Weather Service Nashville TN
238 AM CDT Mon Sep 20 2021

TNZ005>011-023>034-056>066-075-077>080-093>095-211000-
Stewart-Montgomery-Robertson-Sumner-Macon-Clay-Pickett-Houston-
Humphreys-Dickson-Cheatham-Davidson-Wilson-Trousdale-Smith-Jackson-
Putnam-Overton-Fentress-Perry-Hickman-Lewis-Williamson-Maury-
Marshall-Rutherford-Cannon-De Kalb-White-Cumberland-Bedford-Coffee-
Warren-Grundy-Van Buren-Wayne-Lawrence-Giles-
238 AM CDT Mon Sep 20 2021

This Hazardous Weather Outlook is for Middle Tennessee.

.DAY ONE...Today and tonight.

A Flash Flood Watch continues for all of Middle Tennessee through
this evening. Numerous additional showers and a few thunderstorms
with moderate to locally heavy rainfall are expected again today.
Additional rainfall up to 1 to 2 inches is possible today, which may
lead to flash flooding of roads and low lying areas. Rain will
briefly end across the area tonight.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

A strong cold front will move slowly across the area Tuesday
afternoon through Wednesday morning, bringing another round of
showers and thunderstorms. Additional rainfall amounts around 1 to
2 inches are possible, which could cause some localized flooding of
roads and low lying areas. In addition, a couple of strong storms
are possible with gusty winds.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed today due to the risk of flash
flooding. Please relay any information about observed severe weather
to the NWS while following all local, state, and CDC guidelines.

Shamburger

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 19, 8:09 PM CDTRiver Flood WarningOHXBedford, Marshall40 hr
Sep 20, 6:25 AM CDTAreal Flood AdvisoryOHXDickson, Hickman, Lewis, Maury2 hr
Sep 20, 7:08 AM CDTAreal Flood AdvisoryOHXDickson, Montgomery112 min
Sep 20, 9:53 AM CDTAreal Flood AdvisoryOHXBedford, Davidson, Marshall, Rutherford, Williamson112 min
Sep 20, 10:10 AM CDTAreal Flood AdvisoryOHXDickson, Hickman, Lewis, Maury, Williamson2 hr
Sep 20, 10:25 AM CDTFlash Flood WarningOHXDickson, Hickman, Lewis, Maury, Williamson5 hr
Sep 20, 10:32 AM CDTAreal Flood AdvisoryOHXDavidson, Robertson, Rutherford, Sumner, Williamson, Wilson118 min
Sep 20, 10:48 AM CDTAreal Flood AdvisoryOHXBedford, Rutherford4 hr
Sep 20, 11:44 AM CDTAreal Flood AdvisoryOHXRutherford, Wilson3 hr
Sep 20, 12:23 PM CDTAreal Flood AdvisoryOHXDavidson, Rutherford, Sumner, Williamson, Wilson3 hr
Sep 20, 1:02 PM CDTAreal Flood AdvisoryOHXMacon, Sumner, Trousdale, Wilson3 hr
Sep 20, 3:25 PM CDTFlash Flood WarningOHXCheatham, Dickson, Hickman, Lewis, Maury, Williamson5 hr
Sep 20, 3:56 PM CDTAreal Flood AdvisoryOHXGiles, Marshall, Maury, Williamson2 hr
Sep 20, 4:10 PM CDTFlash Flood WarningOHXGiles, Marshall, Maury, Williamson3 hr
Sep 20, 4:26 PM CDTRiver Flood AdvisoryOHXHickman4 hr
Sep 20, 4:34 PM CDTRiver Flood AdvisoryOHXBedford11 hr
Sep 20, 5:59 PM CDTAreal Flood AdvisoryOHXGiles, Lawrence, Lewis, Maury, Wayne3 hr
Sep 20, 6:51 PM CDTFlash Flood WarningOHXGiles, Lawrence, Lewis, Maury, Wayne114 min

Nearby

Areal Flood Advisories in Tennessee, 2021Every areal flood advisory 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.