Alert archive / Tennessee / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 35, NWS Morristown, TN

April 4, 20184 counties in Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Apr 4, 2018, 1:44 AM EDT for 4 counties in Tennessee. It was in force for 46 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Apr 4, 2018, 1:44 AM EDT (05:44 UTC)
Expired: Apr 4, 2018, 2:30 AM EDT
In force: 46 min
Issued by: NWS Morristown, TN
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Blount County, TN, Jefferson County, TN, Knox County, TN, Sevier County, TN

The radar

The Knoxville radar (KMRX), 42 km from the middle of the area, began a volume at 05:45 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 watch it was issued in

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

Issued	Product	Office	Lasted
Apr 3, 9:50 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 5.7 hours before the alert went out and 262 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: 398 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 1862 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 243 m²/s²
0-3 km storm-relative helicity: 349 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 4.8

Open this sounding in Storm Lab

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 Morristown, TN wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 4, 1:05 AM EDT, 39 minutes earlier.

Area forecast discussion, Apr 4, 1:05 AM EDT, 39 minutes before

Area Forecast Discussion
National Weather Service Morristown TN
105 AM EDT Wed Apr 4 2018

.AVIATION...
VFR conditions to change with strong SW winds ahead of a line of
strong thunderstorms moves east across the area. The line is
expected to move through the TAF sites between 06Z and 09Z. Gusty
winds of 35-45 kts and VFR vis but reduction to MVFR or IFR with
heavy rain possible with the storms. Behind line, light rain with
MVFR cigs and good visibility will continue, winds shifting to
the west and northwest and gusty. VFR conditions expected after
sunrise, but winds remain gusty and predominantly westerly.

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...None.
TN...None.
VA...None.
&&

TD

Hazardous weather outlook, Apr 3, 4:17 PM EDT, 9 hours 27 minutes before

Hazardous Weather Outlook...UPDATED
National Weather Service Morristown TN
417 PM EDT Tue Apr 3 2018

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-042030-
Cherokee-Clay-Scott TN-Campbell-Claiborne-Hancock-Hawkins-
Sullivan-Johnson-Morgan-Anderson-Union-Grainger-Hamblen-
Northwest Cocke-Cocke Smoky Mountains-Northwest Greene-
Southeast Greene-Washington TN-Unicoi-Northwest Carter-
Southeast Carter-Roane-Loudon-Knox-Jefferson-NW Blount-
Blount Smoky Mountains-North Sevier-Sevier Smoky Mountains-
Sequatchie-Bledsoe-Rhea-Meigs-McMinn-Northwest Monroe-
Southeast Monroe-Marion-Hamilton-Bradley-West Polk-East Polk-Lee-
Wise-Scott-Russell-Washington-
417 PM EDT Tue Apr 3 2018 /317 PM CDT Tue Apr 3 2018/

This Hazardous Weather Outlook is for portions of Southwest North
Carolina...East Tennessee and Southwest Virginia.

.DAY ONE...Tonight

A cold front will move through the region tonight, bringing
widespread showers and thunderstorms. Some of these thunderstorms
could be severe, with damaging winds and large hail being the
primary threats. An isolated tornado cannot be ruled out. The
line of storms is expected to arrive on the Cumberland Plateau
around midnight, with passage through much of the Tennessee Valley
by around 2-4 am EDT.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

In the hours before

Local storm report, Apr 4, 1:20 AM EDT, 24 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
120 AM EDT WED APR 4 2018

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

1245 AM     TSTM WND DMG     ONEIDA                  36.50N 84.51W
04/04/2018                   SCOTT              TN   911 CALL CENTER

            SEVERAL TREES AND POWERLINES DOWN ACROSS THE COUNTY.

&&

TDOYLE

Local storm report, Apr 4, 1:38 AM EDT, 6 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
138 AM EDT WED APR 4 2018

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

1236 AM     TSTM WND DMG     LA FOLLETTE             36.37N 84.13W
04/04/2018                   CAMPBELL           TN   911 CALL CENTER

            SEVERAL TREES DOWN. TREE ON HOUSE WITH DAMAGE. A TRAILER
            WITH ROOF BLOWN OFF.

&&

TDOYLE

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 3, 11:42 PM EDT	Severe Thunderstorm Warning	MRX	Scott	48 min
Apr 4, 12:08 AM EDT	Severe Thunderstorm Warning	MRX	Bledsoe, Hamilton, Marion, Meigs, Rhea, Sequatchie	67 min
Apr 4, 12:16 AM EDT	Severe Thunderstorm Warning	MRX	Morgan, Scott	44 min
Apr 4, 12:24 AM EDT	Severe Thunderstorm Warning	MRX	Anderson, Campbell, Claiborne, Scott, Union	66 min
Apr 4, 12:59 AM EDT	Severe Thunderstorm Warning	MRX	Anderson, Knox, Loudon, Roane	46 min
Apr 4, 1:15 AM EDT	Severe Thunderstorm Warning	MRX	Bradley, Hamilton, McMinn, Meigs, Rhea	45 min
Apr 4, 1:17 AM EDT	Severe Thunderstorm Warning	MRX	Claiborne, Hancock	43 min
Apr 4, 1:26 AM EDT	Severe Thunderstorm Warning	MRX	Claiborne, Grainger, Hamblen, Hancock, Hawkins, Jefferson and 2 more	64 min
Apr 4, 1:53 AM EDT	Special Weather Statement	MRX	McMinn, Monroe, Polk	52 min
Apr 4, 2:04 AM EDT	Severe Thunderstorm Warning	MRX	Bradley, McMinn, Monroe, Polk	26 min
Apr 4, 2:07 AM EDT	Severe Thunderstorm Warning	MRX	Greene, Hawkins, Sullivan, Washington	38 min
Apr 4, 2:20 AM EDT	Special Weather Statement	MRX	Cocke, Greene	40 min
Apr 4, 2:25 AM EDT	Special Weather Statement	MRX	Sevier	35 min
Apr 4, 2:49 AM EDT	Special Weather Statement	MRX	Carter, Johnson, Sullivan, Washington	56 min
Apr 4, 4:32 AM EDT	Freeze Warning	MRX	Anderson, Bledsoe, Blount, Bradley, Campbell, Carter and 25 more	28 hr
Apr 4, 1:47 AM EDT	Severe Thunderstorm Warning	MRX	Lee, Russell, Scott, Wise, City of Norton	43 min
Apr 4, 2:22 AM EDT	Severe Thunderstorm Warning	MRX	Russell, Washington	38 min
Apr 4, 2:29 AM EDT	Special Weather Statement	MRX	Cherokee, Clay	61 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.