Alert archive / Tennessee / Flash Flood Warnings in 2017

Flash Flood Warning 4, NWS Nashville, TN

April 18, 2017Davidson County, Tennessee

NWS Nashville, TN issued this flash flood warning at Apr 18, 2017, 7:18 PM CDT for Davidson County, Tennessee. It was in force for 4 hr. 2 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: Apr 18, 2017, 7:18 PM CDT (00:18 UTC)
Expired: Apr 18, 2017, 11:00 PM CDT
In force: 4 hr
Issued by: NWS Nashville, TN
Area: Storm-based polygon
Flood severity: None

County Davidson County, TN

The radar

The Nashville radar (KOHX), 31 km from the middle of the area, began a volume at 00:20 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

Time	Report	Where	Remark
Apr 18, 7:30 PM CDT	FLASH FLOOD	Nashville, TN	ROAD BLOCKADE DUE TO FLOODING ALONG GEORGE L DAVIS BLVD
Apr 18, 7:31 PM CDT	FLASH FLOOD	Nashville, TN	BORWNS CREEK OVERFLOWING ITS BANKS ALONG PORTIONS OF SUTTON HILL RD

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 00:00Z, 0.3 hours before the alert went out and 23 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: 366 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 723 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 111 m²/s²
0-3 km storm-relative helicity: 132 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.7

Open this sounding in Storm Lab

The text

As transmitted.

880 
WGUS54 KOHX 190018
FFWOHX
TNC037-190400-
/O.NEW.KOHX.FF.W.0004.170419T0018Z-170419T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Nashville TN
718 PM CDT TUE APR 18 2017

The National Weather Service in Nashville has issued a

* Flash Flood Warning for...
  Davidson County in Middle Tennessee...

* Until 1100 PM CDT

* At 718 PM CDT, Doppler radar indicated numerous showers and 
  isolated thunderstorms with the potential of producing additional 
  rainfall were moving into southern portions of Davidson County 
  that have already experienced saturated ground conditions. Doppler 
  radar estimates showing that over the last three hours that 
  several locations along and south of the I-65...I-24 split in 
  north central Davidson County have received total rainfall amounts 
  ranging from one and a half inches to two and a half inches. 
  Several reports of street flooding have also been received across 
  this area. An additional one half to one inch of rainfall could 
  occur across this area as these numerous showers and isolated 
  thunderstorms continue to move northeast across central and 
  southern portions of Davidson County, along with the potential 
  development of other showers and thunderstorms continuing to to 
  the southwest that may move eventually across this area, through 
  the evening hours.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3611 8654 3601 8660 3601 8661 3597 8663
      3604 8678 3606 8692 3599 8704 3604 8705
      3605 8705 3604 8704 3606 8704 3611 8702
      3614 8700 3620 8699 3624 8697 3624 8660

$$
31

1 follow-up statement

740 
WGUS74 KOHX 190253
FFSOHX

Flash Flood Statement
National Weather Service Nashville TN
953 PM CDT TUE APR 18 2017

TNC037-190400-
/O.CON.KOHX.FF.W.0004.000000T0000Z-170419T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Davidson TN-
953 PM CDT TUE APR 18 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1100 PM CDT FOR
DAVIDSON COUNTY...

At 952 PM CDT, even though most of the rainfall has ended across 
central and southern portions of Davidson County, runoff potential 
still remains, and thus the flash flood warming will remain in 
effect until 1100 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3611 8654 3601 8660 3601 8661 3597 8663
      3604 8678 3606 8692 3599 8704 3604 8705
      3605 8705 3604 8704 3606 8704 3611 8702
      3614 8700 3620 8699 3624 8697 3624 8660

$$

31

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 18, 7:34 PM CDT	Areal Flood Advisory	OHX	Hickman	3 hr
Apr 18, 7:39 PM CDT	Special Weather Statement	OHX	Hickman	21 min
Apr 18, 8:02 PM CDT	Flash Flood Warning	OHX	Williamson	3 hr

Nearby

Flash Flood Warnings in Tennessee, 2017 Every flash flood warning in 2017

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.