Alert archive / Tennessee / Special Weather Statements in 2017

Special Weather Statement, NWS Morristown, TN

April 21, 2017Monroe County, Tennessee

NWS Morristown, TN issued this special weather statement at Apr 21, 2017, 9:37 PM EDT for Monroe County, Tennessee. It was in force for 53 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Apr 21, 2017, 9:37 PM EDT (01:37 UTC)
Expired
Apr 21, 2017, 10:30 PM EDT
In force
53 min
Issued by
NWS Morristown, TN

County Monroe County, TN

The radar

The Knoxville radar (KMRX), 104 km from the middle of the area, began a volume at 01:37 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, 1.6 hours before the alert went out and 243 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 00:00Z on 2017-04-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 47 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 00:00Z on 2017-04-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 133 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
47 J/kg
Mixed-layer CIN
-72 J/kg
Mixed-layer LCL
763 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
133 m²/s²
0-3 km storm-relative helicity
235 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Apr 21, 7:25 PM EDT, 2 hours 12 minutes earlier.

Area forecast discussion, Apr 21, 7:25 PM EDT, 2 hours 12 minutes before
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Hazardous weather outlook, Apr 21, 3:56 AM EDT, 17 hours 41 minutes before
Hazardous Weather Outlook
National Weather Service Morristown TN
356 AM EDT Fri Apr 21 2017

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-220800-
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-
356 AM EDT Fri Apr 21 2017 /256 AM CDT Fri Apr 21 2017/

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

.DAY ONE...Today and Tonight

...Strong to Possibly Severe Storms are expected this Afternoon
and Evening...

A cold front will move into the region Today producing scattered
to numerous showers and thunderstorms. Some of these storms could
be strong to possibly severe from the mid-afternoon to early
evening. The main concern being hail up to quarter size, damaging
downburst winds up to 60 mph, heavy rainfall and lightning.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

...Strong to Severe Storms possible Saturday Afternoon and
Evening...
...Locally Heavy Rainfall and Flash Flooding are possible from
late Saturday through Sunday...

A storm system will move across the Tennessee Valley Saturday
interacting with a frontal boundary to produce widespread storms
across middle Tennessee and northern Alabama by mid-day. These
storms will move into east Tennessee and southwest North Carolina
by late afternoon and evening. Some of these thunderstorms may be
strong to severe producing large hail, strong damaging winds,
heavy rainfall and frequent lightning.

Periods of showers and isolated thunderstorms will continue
through Sunday, especially across southwest Virginia and northeast
Tennessee. The heavy rainfall late may produce localized flash
flooding.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed late Saturday afternoon and
evening.

In the hours before

Special weather statement, Apr 21, 3:51 PM EDT, 5 hours 46 minutes before
Special Weather Statement
National Weather Service Morristown TN
351 PM EDT FRI APR 21 2017

TNZ014-037-212045-
Claiborne TN-Union TN-
351 PM EDT FRI APR 21 2017

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL CLAIBORNE AND NORTHERN
UNION COUNTIES UNTIL 445 PM EDT...

At 350 PM EDT, Doppler radar was tracking a strong thunderstorm 12
miles south of Pruden, or 12 miles north of Maynardville, moving east
at 15 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
New Tazewell, Tazewell, Harrogate, Springdale, Lone Mountain, Arthur,
Powell River Preserve, Sandlick and Cumberland Gap.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3660 8357 3639 8348 3635 8394 3638 8396
      3640 8395 3639 8393 3640 8391 3643 8390
      3643 8392 3647 8394 3659 8370 3658 8369
      3660 8366
TIME...MOT...LOC 1950Z 249DEG 12KT 3642 8389

05/MA
Special weather statement, Apr 21, 4:21 PM EDT, 5 hours 16 minutes before
Special Weather Statement
National Weather Service Morristown TN
421 PM EDT FRI APR 21 2017

TNZ036-069-212115-
Anderson TN-Knox TN-
421 PM EDT FRI APR 21 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN KNOX AND SOUTHEASTERN
ANDERSON COUNTIES UNTIL 515 PM EDT...

At 421 PM EDT, Doppler radar was tracking a strong thunderstorm near
Clinton, moving northeast at 20 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Knoxville, Oak Ridge, Clinton, Halls, Norris, Andersonville, House
Mountain S.p., Maloneyville, Powell and Mascot.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3621 8397 3617 8392 3617 8391 3616 8391
      3617 8390 3616 8375 3610 8371 3598 8421
      3608 8428 3625 8400
TIME...MOT...LOC 2021Z 242DEG 16KT 3606 8418

05/MA
Special weather statement, Apr 21, 8:03 PM EDT, 1 hour 34 minutes before
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Special weather statement, Apr 21, 9:37 PM EDT, 0 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Apr 22, 4:11 AM EDTFlash Flood WatchMRXAnderson, Bledsoe, Blount, Bradley, Campbell, Carter and 27 more47 hr
Apr 22, 8:55 AM EDTAreal Flood AdvisoryMRXAnderson, Campbell, Claiborne, Morgan, Scott, Union4 hr
Apr 22, 9:14 AM EDTRiver Flood WarningMRXClaiborne, Grainger, Hancock4 days
Apr 22, 9:14 AM EDTRiver Flood WarningMRXHawkins, Sullivan3 days
Apr 22, 11:04 AM EDTAreal Flood AdvisoryMRXHancock3 hr
Apr 22, 4:40 PM EDTSpecial Weather StatementMRXAnderson50 min
Apr 22, 4:56 PM EDTSevere Thunderstorm WarningMRXAnderson, Knox64 min
Apr 22, 5:28 PM EDTAreal Flood AdvisoryMRXAnderson, Blount, Grainger, Jefferson, Knox, Loudon and 4 more3 hr
Apr 22, 5:33 PM EDTSevere Thunderstorm WarningMRXJefferson, Sevier57 min
Apr 22, 5:44 PM EDTSpecial Weather StatementMRXSequatchie46 min
Apr 22, 5:49 PM EDTFlash Flood WarningMRXAnderson, Blount, Knox, Loudon, Morgan, Roane and 1 more3 hr
Apr 22, 6:07 PM EDTSevere Thunderstorm WarningMRXBledsoe, Hamilton, Meigs, Rhea, Sequatchie53 min
Apr 22, 6:19 PM EDTSevere Thunderstorm WarningMRXCocke56 min
Apr 22, 6:29 PM EDTAreal Flood AdvisoryMRXBledsoe, Hamilton, Marion, Meigs, Rhea, Sequatchie2 hr
Apr 22, 6:29 PM EDTSpecial Weather StatementMRXBlount46 min
Apr 22, 6:38 PM EDTSevere Thunderstorm WarningMRXLoudon, McMinn, Monroe, Roane51 min
Apr 22, 6:53 PM EDTAreal Flood WarningMRXAnderson, Campbell, Morgan, Scott, Union112 min
Apr 22, 7:06 PM EDTRiver Flood WarningMRXMorgan, Roane15 hr
Apr 22, 7:21 PM EDTSpecial Weather StatementMRXBlount, Sevier39 min
Apr 22, 7:24 PM EDTAreal Flood AdvisoryMRXCarter, Claiborne, Grainger, Greene, Hamblen, Hancock and 5 more3 hr
Apr 21, 8:03 PM EDTSpecial Weather StatementMRXWashington, City of Bristol42 min
Apr 22, 11:09 AM EDTSpecial Weather StatementMRXRussell51 min
Apr 22, 5:57 PM EDTAreal Flood AdvisoryMRXLee, Russell, Scott3 hr
Apr 22, 12:29 PM EDTSpecial Weather StatementMRXWatauga31 min

Nearby

Special Weather Statements in Tennessee, 2017Every special weather statement 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.