Alert archive / Tennessee / Flash Flood Watches in 2020

Flash Flood Watch 4, NWS Nashville, TN

April 11, 202038 counties in Tennessee

NWS Nashville, TN issued this flash flood watch at Apr 11, 2020, 9:03 PM CDT for 38 counties in Tennessee. It took effect at Apr 12, 2020, 12:00 PM CDT. It was in force for 19 hr.

The area

The counties it named.

The facts

Issued: Apr 11, 2020, 9:03 PM CDT (02:03 UTC)
In effect from: Apr 12, 2020, 12:00 PM CDT
Expired: Apr 13, 2020, 7:00 AM CDT
In force: 19 hr
Issued by: NWS Nashville, TN
Flood severity: None

All 38 counties

Bedford County, TN, Cannon County, TN, Cheatham County, TN, Clay County, TN, Coffee County, TN, Cumberland County, TN, Davidson County, TN, DeKalb County, TN, Dickson County, TN, Fentress County, TN, Giles County, TN, Grundy County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Jackson County, TN, Lawrence County, TN, Lewis County, TN, Macon County, TN, Marshall County, TN, Maury County, TN, Montgomery County, TN, Overton County, TN, Perry County, TN, Pickett County, TN, Putnam County, TN, Robertson County, TN, Rutherford County, TN, Smith County, TN, Stewart County, TN, Sumner County, TN, Trousdale County, TN, Van Buren County, TN, Warren County, TN, Wayne County, TN, White County, TN, Williamson County, TN, Wilson County, TN

The radar

The Nashville radar (KOHX), 30 km from the middle of the area, began a volume at 02:07 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 00:00Z, 2.1 hours before the alert went out and 20 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2991 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 103 m²/s²
0-3 km storm-relative helicity: 402 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 flash flood watch 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 flash flood watch went out at Apr 11, 7:03 PM CDT, 2 hours earlier.

Area forecast discussion, Apr 11, 7:03 PM CDT, 2 hours before

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Hazardous weather outlook, Apr 11, 8:10 PM CDT, 53 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 11, 9:10 PM CDT	Wind Advisory	OHX	Bedford, Cannon, Cheatham, Clay, Coffee, Cumberland and 32 more	37 hr
Apr 12, 9:56 AM CDT	Special Weather Statement	OHX	Giles, Lawrence, Wayne	34 min
Apr 12, 10:36 AM CDT	Special Weather Statement	OHX	Giles, Lawrence	24 min
Apr 12, 4:04 PM CDT	Special Weather Statement	OHX	Marshall, Maury	26 min
Apr 12, 4:08 PM CDT	Special Weather Statement	OHX	Hickman, Lawrence, Lewis, Perry, Wayne	37 min
Apr 12, 4:10 PM CDT	Areal Flood Advisory	OHX	Bedford, Giles, Lawrence, Marshall, Maury	3 hr
Apr 12, 4:34 PM CDT	Special Weather Statement	OHX	Maury, Williamson	41 min
Apr 12, 4:41 PM CDT	Areal Flood Advisory	OHX	Davidson, Rutherford, Smith, Sumner, Trousdale, Williamson and 1 more	3 hr
Apr 12, 4:53 PM CDT	Severe Thunderstorm Warning	OHX	Davidson, Rutherford, Williamson, Wilson	22 min
Apr 12, 5:08 PM CDT	Special Weather Statement	OHX	Sumner, Trousdale	37 min
Apr 12, 5:23 PM CDT	Special Weather Statement	OHX	Bedford, Cannon, Rutherford	37 min

Nearby

Flash Flood Watches in Tennessee, 2020 Every flash flood watch 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.