Alert archive / North Carolina / Areal Flood Advisories in 2021

Areal Flood Advisory 13, NWS Morristown, TN

March 25, 2021Polk County, Tennessee; Cherokee County, Clay County, North Carolina

NWS Morristown, TN issued this areal flood advisory at Mar 25, 2021, 7:57 PM EDT for Polk County, Tennessee; Cherokee County, Clay County, North Carolina. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
Mar 25, 2021, 7:57 PM EDT (23:57 UTC)
Expired
Mar 25, 2021, 11:47 PM EDT
In force
4 hr
Issued by
NWS Morristown, TN
Area
Storm-based polygon

Counties Cherokee County, NC, Clay County, NC, Polk County, TN

The radar

The Knoxville radar (KMRX), 135 km from the middle of the area, began a volume at 23:57 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

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 12.0 hours before the alert went out and 196 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, Peachtre/Fal Fld, GA at 12:00Z on 2021-03-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Peachtre/Fal Fld, GA at 12:00Z on 2021-03-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 397 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1602 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
397 m²/s²
0-3 km storm-relative helicity
647 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood advisory 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 areal flood advisory went out at Mar 25, 7:42 PM EDT, 15 minutes earlier.

Area forecast discussion, Mar 25, 7:42 PM EDT, 15 minutes before
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Hazardous weather outlook, Mar 25, 2:44 PM EDT, 5 hours 13 minutes before
Hazardous Weather Outlook
National Weather Service Morristown TN
244 PM EDT Thu Mar 25 2021

NCZ061-TNZ014>018-037>047-070-073-074-VAZ001-002-005-006-008-
261845-
Clay-Claiborne-Hancock-Hawkins-Sullivan-Johnson-Union-Grainger-
Hamblen-Northwest Cocke-Cocke Smoky Mountains-Northwest Greene-
Southeast Greene-Washington-Unicoi-Northwest Carter-
Southeast Carter-Jefferson-North Sevier-Sevier Smoky Mountains-
Lee-Wise-Scott-Russell-
244 PM EDT Thu Mar 25 2021

This Hazardous Weather Outlook is for portions of southwest North
Carolina...east Tennessee and southwest Virginia.

.DAY ONE...This Afternoon and Tonight

Severe thunderstorms are possible this afternoon and tonight with
moderate to heavy rainfall expected. The primary hazards will be
damaging winds. However, there remains a threat for a few
tornadoes this evening and tonight, and a few of the stronger
storms could have damaging hail. There is a threat for localized
flash flooding as rainfall rates will be high. See the Flash Flood
Watch for additional information.

Strong winds are also expected across the area this afternoon into
tonight with gusts likely in excess of 40 mph area-wide. See the
Wind Advisory for additional information. Damaging winds are
expected in the Tennessee mountains and adjacent foothills this
afternoon into tonight where gusts will likely exceed 70 mph. See
the High Wind Warning for additional information.

.DAYS TWO THROUGH SEVEN...Friday through Thursday

There could be some storms Saturday afternoon and evening, a few
strong. Heavy rains could cause some isolated flooding problems
Saturday night into Sunday morning.

.SPOTTER INFORMATION STATEMENT...

Spotter reports will be needed this afternoon into tonight.

NCZ060-TNZ012-013-035-036-067>069-071-072-081>087-098>102-261845-
Cherokee-Scott-Campbell-Morgan-Anderson-Roane-Loudon-Knox-
Northwest Blount-Blount Smoky Mountains-Sequatchie-Bledsoe-Rhea-
Meigs-McMinn-Northwest Monroe-Southeast Monroe-Marion-Hamilton-
Bradley-West Polk-East Polk-
244 PM EDT Thu Mar 25 2021 /144 PM CDT Thu Mar 25 2021/

This Hazardous Weather Outlook is for portions of southwest North
Carolina and east Tennessee.

.DAY ONE...This Afternoon and Tonight

There remains a threat for a tornadoes late this afternoon and
into tonight, a few possibly isolated strong tornadoes. Also,
some storms will have damaging storm winds, and damaging hail from
the strongest storms. There is a threat for localized flash
flooding as rainfall rates will be high. See the Flash Flood Watch
for additional information.

Strong winds are also expected across the area this afternoon into
tonight with gusts likely in excess of 40 mph area-wide. See the
Wind Advisory for additional information. Damaging winds are
expected in the Tennessee mountains and adjacent foothills this
afternoon into tonight where gusts will likely exceed 70 mph. See
the High Wind Warning for additional information.

.DAYS TWO THROUGH SEVEN...Friday through Thursday

There could be some strong to possibly severe storms on and near
the Plateau Saturday afternoon and into Saturday evening.  Heavy
rains could cause some isolated flooding problems Saturday night
into Sunday morning.

.SPOTTER INFORMATION STATEMENT...

Spotter reports will be needed this afternoon into tonight.

In the hours before

Local storm report, Mar 25, 2:12 PM EDT, 5 hours 45 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
212 PM EDT THU MAR 25 2021

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

0211 PM     FLASH FLOOD      4 NW EAST BRAINERD      35.05N 85.16W
03/25/2021                   HAMILTON           TN   LAW ENFORCEMENT

            SEVERAL ROADWAYS ARE FLOODED AND BARRICADED
            ACROSS HAMILTON COUNTY.

&&

DH
Special weather statement, Mar 25, 4:14 PM EDT, 3 hours 43 minutes before
Special Weather Statement
National Weather Service Morristown TN
314 PM CDT Thu Mar 25 2021

TNZ082-252045-
Bledsoe TN-
314 PM CDT Thu Mar 25 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL BLEDSOE COUNTY
UNTIL 345 PM CDT...

At 313 PM CDT, Doppler radar was tracking a strong thunderstorm 8
miles northwest of Pikeville, moving northeast at 60 mph.

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

Locations impacted include...
Mount Crest.

LAT...LON 3571 8528 3572 8526 3575 8527 3575 8526
      3576 8526 3577 8510 3576 8509 3564 8527
      3567 8531
TIME...MOT...LOC 2013Z 224DEG 50KT 3571 8526

JLB
Local storm report, Mar 25, 7:02 PM EDT, 55 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
702 PM EDT THU MAR 25 2021

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

0645 PM     FLOOD            KNOXVILLE               35.97N 83.95W
03/25/2021                   KNOX               TN   BROADCAST MEDIA

            STREET FLOODING AT THE INTERSECTION OF CEDAR
            BLUFF AND PARK WEST BLVD.

&&

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 25, 3:41 AM EDTWind AdvisoryMRXAnderson, Bledsoe, Blount, Bradley, Campbell, Carter and 25 more24 hr
Mar 25, 10:22 AM EDTRiver Flood WarningMRXBledsoe, Marion, Sequatchie4 days
Mar 25, 10:53 AM EDTSevere Thunderstorm WarningMRXHamilton, Marion33 min
Mar 25, 11:20 AM EDTSpecial Weather StatementMRXBradley, Polk40 min
Mar 25, 1:03 PM EDTFlash Flood WarningMRXBradley, Hamilton, Marion, Sequatchie3 hr
Mar 25, 2:28 PM EDTAreal Flood AdvisoryMRXPolk3 hr
Mar 25, 2:52 PM EDTRiver Flood WarningMRXHamilton41 hr
Mar 25, 4:06 PM EDTAreal Flood AdvisoryMRXBradley, Hamilton, Marion, Sequatchie86 min
Mar 25, 4:14 PM EDTSpecial Weather StatementMRXBledsoe31 min
Mar 25, 5:27 PM EDTFlash Flood WarningMRXBradley, Hamilton, Marion, Sequatchie4 hr
Mar 25, 6:17 PM EDTAreal Flood AdvisoryMRXKnox, Loudon3 hr
Mar 25, 7:17 PM EDTRiver Flood WarningMRXCocke32 hr
Mar 25, 1:02 PM EDTSpecial Weather StatementMRXClay28 min

Nearby

Areal Flood Advisories in North Carolina, 2021Areal Flood Advisories in Tennessee, 2021Every areal flood advisory in 2021

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.