Alert archive / Tennessee / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 51, NWS Morristown, TN

April 17, 2017Rhea County, Roane County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at Apr 17, 2017, 6:21 PM EDT for Rhea County, Roane County, Tennessee. It was in force for 39 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 17, 2017, 6:21 PM EDT (22:21 UTC)
Expired
Apr 17, 2017, 7:00 PM EDT
In force
39 min
Issued by
NWS Morristown, TN
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Rhea County, TN, Roane County, TN

The radar

The Knoxville radar (KMRX), 129 km from the middle of the area, began a volume at 22:22 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 12:00Z, 10.4 hours before the alert went out and 175 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, Nashville Metro, TN at 12:00Z on 2017-04-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 110 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, Nashville Metro, TN at 12:00Z on 2017-04-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 square meters per square second.193958Sfc1 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
110 J/kg
Mixed-layer CIN
-66 J/kg
Mixed-layer LCL
867 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
87 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 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 17, 2:43 PM EDT, 3 hours 38 minutes earlier.

Area forecast discussion, Apr 17, 2:43 PM EDT, 3 hours 38 minutes before
Area Forecast Discussion
National Weather Service Morristown TN
243 PM EDT Mon Apr 17 2017

.SHORT TERM (Today through tomorrow)...
Showers from this morning have nearly exited our northern counties
in Southwest Virginia and new storms are moving in from Middle
Tennessee. Most of these storms are just isolated heavy showers,
but the strongest of them do have a bit of lightning as well. Not
expecting anything in the form of severe weather this afternoon or
tonight. Thunderstorms will generally stay in the middle/southern
half of the Tennessee, generally south of the boundary that is
set up over us. More widespread precipitation could move over the
area late tonight once the thunderstorms have dissipated. Could
see some patchy fog overnight as well with the showers today, but
widespread fog is not expected since mostly cloudy skies overnight
should keep dense fog away. Similar temperatures can be expected
tomorrow along with another round of showers and thunderstorms.

.LONG TERM (Tuesday night through Monday)...
Models in decent agreement early on, although differences
increase during the period. Forecast confidence is a bit below
normal for this time of year in this active pattern. Numerous
showers and thunderstorms will continue into Tuesday night with
the exiting short wave energy, but should diminish overnight.
Looks like there will be enough moisture and instability lingering
over the area Wed and Thu for some isolated to scattered
convection, then a cold front is forecast to push through Thursday
night/early Friday for a better chance of showers and
thunderstorms. A stronger upper trough/perhaps closed upper low is
forecast to affect the region over the weekend, bringing more
unsettled weather both days. Will carry highest chance for showers
and thunderstorms Saturday night into Sunday for right now, but
timing of this system still rather uncertain. Cooler and drier air
should be moving in for Monday, although there still may be a
lingering shower.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             61  76  59  80 /  60  60  50  50
Knoxville McGhee Tyson Airport, TN  58  75  59  77 /  60  60  50  40
Oak Ridge, TN                       59  75  59  78 /  60  60  40  50
Tri Cities Airport, TN              52  73  52  75 /  60  40  40  50

&&

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

ABM/LW
Hazardous weather outlook, Apr 17, 3:04 AM EDT, 15 hours 17 minutes before
Hazardous Weather Outlook
National Weather Service Morristown TN
304 AM EDT Mon Apr 17 2017

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-180715-
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-
304 AM EDT Mon Apr 17 2017 /204 AM CDT Mon Apr 17 2017/

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

.DAY ONE...Today and Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

In the hours before

Special weather statement, Apr 17, 3:34 PM EDT, 2 hours 47 minutes before
Special Weather Statement
National Weather Service Morristown TN
334 PM EDT MON APR 17 2017

TNZ069-071-073-172015-
Knox TN-NW Blount TN-North Sevier TN-
334 PM EDT MON APR 17 2017

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN KNOX...NORTHWESTERN
BLOUNT AND NORTHWESTERN SEVIER COUNTIES UNTIL 415 PM EDT...

At 333 PM EDT, Doppler radar was tracking a strong thunderstorm over
Louisville, or near Alcoa, moving northeast at 25 mph.

Dime size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Knoxville, Maryville, Sevierville, Alcoa, Farragut, Louisville,
Rockford, Eagleton Village, Kimberlin Heights, Wildwood, McMahan,
Lake Forest, Mascot, Bearden and Seymour.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3572 8403 3588 8414 3611 8375 3588 8358
TIME...MOT...LOC 1933Z 240DEG 20KT 3584 8401
Special weather statement, Apr 17, 4:35 PM EDT, 1 hour 46 minutes before
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Special weather statement, Apr 17, 5:57 PM EDT, 24 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Apr 17, 3:34 PM EDTSpecial Weather StatementMRXKnox41 min
Apr 17, 4:35 PM EDTSpecial Weather StatementMRXSequatchie40 min
Apr 17, 4:54 PM EDTAreal Flood AdvisoryMRXBledsoe, Sequatchie2 hr
Apr 17, 5:57 PM EDTSpecial Weather StatementMRXRhea33 min
Apr 17, 7:28 PM EDTAreal Flood AdvisoryMRXBledsoe, Sequatchie3 hr

Nearby

Severe Thunderstorm Warnings in Tennessee, 2017Every severe thunderstorm 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.