Alert archive / Tennessee / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 140, NWS Nashville, TN

July 20, 2018Jackson County, Putnam County, White County, Tennessee

NWS Nashville, TN issued this severe thunderstorm warning at Jul 20, 2018, 8:52 PM CDT for Jackson County, Putnam County, White County, Tennessee. It was in force for 23 min. 4 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: Jul 20, 2018, 8:52 PM CDT (01:52 UTC)
Expired: Jul 20, 2018, 9:15 PM CDT
In force: 23 min
Issued by: NWS Nashville, TN
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Jackson County, TN, Putnam County, TN, White County, TN

The radar

The Nashville radar (KOHX), 92 km from the middle of the area, began a volume at 01:52 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
Jul 20, 9:15 PM CDT	TSTM WND DMG	4 Nw Cookeville, TN	DELAYED REPORT FROM FRIDAY JULY 20. SEVERAL TREES BLOWN DOWN ON WAKEFIELD DRIVE NEAR COUNTY FARM ROAD
Jul 20, 9:17 PM CDT	TSTM WND DMG	4 Wnw Cookeville, TN	DELAYED REPORT FROM FRIDAY JULY 20. SEVERAL TREES SNAPPED AND UPROOTED AROUND THE POST OAK SHADE CHURCH AT THOMAS ROAD AND PIPPIN ROAD INTERSECTION
Jul 20, 9:20 PM CDT	TSTM WND DMG	2 Wnw Cookeville, TN	DELAYED REPORT FROM FRIDAY JULY 20. CANE CREEK PARK MOUNTAIN BIKE TRAIL CLOSED FOR 2 TO 3 WEEKS DUE TO NUMEROUS TREES DOWN BLOCKING THE TRAIL.
Jul 20, 9:22 PM CDT	HAIL 1	3 S Cookeville, TN	REPORT OF QUARTER SIZE HAIL SOUTH OF COOKEVILLE IN PUTNAM COUNTY.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched one storm report to this severe thunderstorm warning; the first came 23 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 20, 6:22 PM CDT	Tornado Watch	SPC	8 hr

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 1.9 hours before the alert went out and 96 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: 3305 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 1217 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 90 m²/s²
0-3 km storm-relative helicity: 169 m²/s²
Significant tornado parameter: 2.2
Supercell composite: 11.6

Open this sounding in Storm Lab

The text

As transmitted.

986 
WUUS54 KOHX 210152
SVROHX
TNC087-141-185-210215-
/O.NEW.KOHX.SV.W.0140.180721T0152Z-180721T0215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Nashville TN
852 PM CDT FRI JUL 20 2018

The National Weather Service in Nashville has issued a

* Severe Thunderstorm Warning for...
  Southeastern Jackson County in Middle Tennessee...
  Northwestern White County in Middle Tennessee...
  Western Putnam County in Middle Tennessee...

* Until 915 PM CDT.

* At 851 PM CDT, a severe thunderstorm was located over Baxter, or 8
  miles west of Cookeville, moving southeast at 25 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Cookeville, Gainesboro, Algood, Baxter, Hamptons Crossroads, Bakers
  Crossroads, Burgess Falls State Park and Cummins Falls State Park.

This includes Interstate 40 between mile markers 275 and 289.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

A Tornado Watch remains in effect until 200 AM CDT for Middle
Tennessee.

LAT...LON 3633 8550 3630 8549 3630 8546 3628 8545
      3628 8547 3624 8542 3600 8551 3603 8563
      3613 8575 3634 8574
TIME...MOT...LOC 0151Z 294DEG 23KT 3619 8566 

HAIL...1.00IN
WIND...60MPH
 
$$

Whitehead

What forecasters said that day

The local office's own words before this severe thunderstorm warning 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 severe thunderstorm warning went out at Jul 20, 7:35 PM CDT, 1 hour 17 minutes earlier.

Area forecast discussion, Jul 20, 7:35 PM CDT, 1 hour 17 minutes before

Area Forecast Discussion
National Weather Service Nashville TN
735 PM CDT Fri Jul 20 2018

.DISCUSSION...

Updated the suite of forecast products to reflect the issuance of
Tornado Watch 294 for all of Middle TN until 2 AM CDT. With some
short term models showing the potential for rounds of shwrs/tstms
thru the watch period, went with periods of shwrs/tstms for the
entire mid state during this period. Also highlighted in the
text the potential of damaging winds, large hail, isolated
tornadoes, and frequent cloud to ground lightning through
the evening into the early morning hrs on Sat. Tweaked hrly
temps, dewpoint, and wind speed/direction grids. Remainder
of the forecast continues to be on track.

&&

.DISCUSSION...

Updated late this afternoon wording in zone forecast product to
emphasize most of the potential impacts of shwrs/tstms, some tstms
possibly svr, after 7/21Z (7 PM CDT Tonight). Tweaked hrly temp,
dewpoint, and wind speed/direction grids. Initially, remainder of
the forecast looks like it continues to be on track.

&&

.AVIATION...
00Z TAF DISCUSSION.

CKV/BNA/MQY/CSV...With so much uncertainty to what actual impacts
will occur at specific terminals with potentially rounds of
shwrs/tstms, no continuous throughout period/hard to pinpoint
if they will actually develop and/or move over specific terminals.
Some of those tstms could be svr also. Thus mentioned VCTS at all
terminals 21/00Z-21/04Z, with TEMPO groups of predominate MVFR
vsbys/ceilings, and wind gusts to 30-35kts in between. Several
amendments possible thru at least the first half of valid TAF
periods because of this uncertainty. Maybe some lingering
shwrs/tstms after 21/07Z, but as of this time main impacts on
terminals look to end by that point. It looks like another round
of shwrs/tstms potentially 21/18Z-21/24Z. Will at least mention
VCTS at all terminals again as actual uncertainty continues in
actual impacts at terminal sites, but can certainly not rule out
development in vcnty.

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

DISCUSSION......31
AVIATION........31

Hazardous weather outlook, Jul 20, 8:38 PM CDT, 14 minutes before

Hazardous Weather Outlook...UPDATED
National Weather Service Nashville TN
838 PM CDT Fri Jul 20 2018

TNZ005>011-023>034-056>066-075-077>080-093>095-220145-
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-
838 PM CDT Fri Jul 20 2018

This Hazardous Weather Outlook is for portions of Middle
Tennessee.

.DAY ONE...Tonight

There is a moderate risk for severe thunderstorms tonight for
locations generally around and north of a Linden to Centerville
to Franklin to Carthage to Celina line. There is an enhanced
risk for severe thunderstorms for the remainder of Middle
Tennessee. Scattered to numerous showers and thunderstorms are
expected to develop through the evening hours across southern
Kentucky, then spread southeastward across Middle Tennessee into
this evening and overnight. With severe thunderstorms that do
develop, large hail, damaging winds, frequent cloud to ground
lightning strikes, isolated tornadoes, and brief heavy rainfall
will be possible.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

There is a slight risk for severe thunderstorms across the
southeast half of Middle Tennessee on Saturday afternoon into
Saturday evening. There is a marginal risk for the rest of the
mid state region Saturday afternoon into Saturday evening.
A few strong to severe thunderstorms containing damaging winds
and or large hail will be possible.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is requested for tonight and might once again
be needed Saturday afternoon into Saturday evening across Middle
Tennessee.

Spotter Thunderstorm Reporting Criteria...

Tornado
Funnel Cloud
Flooding
Hail >= 1/2 inch
Wind > 50 mph (measured)
Structural Damage
Trees or power lines down

31

In the hours before

Local storm report, Jul 20, 8:30 PM CDT, 22 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NASHVILLE TN
830 PM CDT FRI JUL 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0829 PM     HAIL             COOKEVILLE              36.16N  85.51W
07/20/2018  E0.88 INCH       PUTNAM             TN   MEDIA

            REPORT OF NICKEL SIZE HAIL IN COOKEVILLE.

&&

EVENT NUMBER OHX1800298

MACDONALD

Local storm report, Jul 20, 8:32 PM CDT, 20 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NASHVILLE TN
832 PM CDT FRI JUL 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0831 PM     HAIL             COOKEVILLE              36.16N  85.51W
07/20/2018  E1.25 INCH       PUTNAM             TN   SOCIAL MEDIA

            TSPOTTER REPORT OF HAIL IN COOKEVILLE. LARGER THAN A
            QUARTER IN COMPARISON.

&&

EVENT NUMBER OHX1800299

MACDONALD

Local storm report, Jul 20, 8:34 PM CDT, 18 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NASHVILLE TN
834 PM CDT FRI JUL 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0834 PM     HAIL             LIVINGSTON              36.39N  85.33W
07/20/2018  E1.00 INCH       OVERTON            TN   NWS EMPLOYEE

&&

EVENT NUMBER OHX1800300

BW

Local storm report, Jul 20, 8:35 PM CDT, 17 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NASHVILLE TN
835 PM CDT FRI JUL 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0833 PM     TSTM WND DMG     1 SSE CUMMINS FALLS STA 36.24N  85.56W
07/20/2018                   JACKSON            TN   911 CALL CENTER

            TREES DOWN WITH POWER OUTAGES ON CUMMINS MILL RD.

&&

EVENT NUMBER OHX1800301

MACDONALD

Local storm report, Jul 20, 8:36 PM CDT, 16 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NASHVILLE TN
836 PM CDT FRI JUL 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0808 PM     TSTM WND DMG     CELINA                  36.55N  85.50W
07/20/2018                   CLAY               TN   EMERGENCY MNGR

            SEVERAL TREES DOWN ON MOSS ARCOT ROAD.

&&

EVENT NUMBER OHX1800302

MACDONALD

Local storm report, Jul 20, 8:50 PM CDT, 2 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NASHVILLE TN
850 PM CDT FRI JUL 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0835 PM     TSTM WND DMG     5 N ALGOOD              36.26N  85.45W
07/20/2018                   PUTNAM             TN   EMERGENCY MNGR

            TREES DOWN NEAR ZEB WARREN ROAD AND BEN MASON ROAD.

&&

EVENT NUMBER OHX1800303

MACDONALD

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 7:12 PM CDT	Severe Thunderstorm Warning	OHX	Clay, Fentress, Jackson, Overton, Pickett	48 min
Jul 20, 7:27 PM CDT	Severe Thunderstorm Warning	OHX	Clay	33 min
Jul 20, 7:46 PM CDT	Severe Thunderstorm Warning	OHX	Jackson, Overton, Putnam	44 min
Jul 20, 7:56 PM CDT	Severe Thunderstorm Warning	OHX	Clay, Jackson, Overton, Pickett	49 min
Jul 20, 8:23 PM CDT	Severe Thunderstorm Warning	OHX	Cumberland, Overton, Putnam, White	52 min
Jul 20, 8:34 PM CDT	Tornado Warning	OHX	Cumberland, Fentress, Overton, Putnam	26 min
Jul 20, 8:47 PM CDT	Tornado Warning	OHX	Cumberland, Putnam, White	28 min
Jul 20, 9:10 PM CDT	Tornado Warning	OHX	Cumberland, White	35 min
Jul 20, 9:14 PM CDT	Severe Thunderstorm Warning	OHX	Overton, Putnam, White	46 min
Jul 20, 9:44 PM CDT	Severe Thunderstorm Warning	OHX	Cumberland, Van Buren, White	46 min
Jul 20, 9:48 PM CDT	Areal Flood Advisory	OHX	Cumberland, Putnam, White	3 hr
Jul 20, 10:20 PM CDT	Special Weather Statement	OHX	Pickett	40 min
Jul 20, 10:40 PM CDT	Special Weather Statement	OHX	Van Buren	35 min
Jul 20, 11:25 PM CDT	Special Weather Statement	OHX	Cumberland	35 min
Jul 20, 11:48 PM CDT	Special Weather Statement	OHX	Jackson, Overton	42 min
Jul 21, 12:02 AM CDT	Severe Thunderstorm Warning	OHX	Jackson, Overton, Putnam	28 min
Jul 21, 12:15 AM CDT	Special Weather Statement	OHX	Clay, Fentress, Macon, Pickett	45 min
Jul 21, 12:27 AM CDT	Severe Thunderstorm Warning	OHX	Jackson, Overton, Putnam	33 min
Jul 21, 12:39 AM CDT	Special Weather Statement	OHX	Trousdale	51 min
Jul 21, 12:48 AM CDT	Severe Thunderstorm Warning	OHX	Cumberland, Fentress, Overton, Putnam	57 min
Jul 21, 12:52 AM CDT	Areal Flood Advisory	OHX	Jackson, Overton, Putnam	2 hr
Jul 21, 1:01 AM CDT	Special Weather Statement	OHX	Jackson, Overton, Putnam, Smith	44 min
Jul 21, 1:21 AM CDT	Severe Thunderstorm Warning	OHX	DeKalb, Smith, Sumner, Trousdale, Wilson	39 min
Jul 21, 1:53 AM CDT	Areal Flood Advisory	OHX	DeKalb, Smith, Wilson	2 hr
Jul 21, 2:04 AM CDT	Special Weather Statement	OHX	Cannon, DeKalb, Van Buren, Warren, White, Wilson	56 min
Jul 21, 2:38 AM CDT	Severe Thunderstorm Warning	OHX	Coffee, Grundy	52 min
Jul 21, 2:55 AM CDT	Special Weather Statement	OHX	Macon, Sumner	65 min
Jul 21, 3:38 AM CDT	Special Weather Statement	OHX	Smith, Trousdale, Wilson	67 min
Jul 21, 4:52 AM CDT	Special Weather Statement	OHX	DeKalb	23 min
Jul 21, 5:04 AM CDT	Severe Thunderstorm Warning	OHX	DeKalb, Putnam, Van Buren, White	28 min
Jul 21, 5:31 AM CDT	Severe Thunderstorm Warning	OHX	Cumberland, Van Buren, Warren, White	29 min
Jul 21, 7:35 AM CDT	Special Weather Statement	OHX	Putnam	40 min

Nearby

Severe Thunderstorm Warnings in Tennessee, 2018 Every severe thunderstorm warning in 2018

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.