Alert archive / Tennessee / Areal Flood Warnings in 2018

Areal Flood Warning 13, NWS Morristown, TN

February 28, 20184 counties in Tennessee

NWS Morristown, TN issued this areal flood warning at Feb 28, 2018, 4:45 PM EST for 4 counties in Tennessee. It was in force for 9 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Feb 28, 2018, 4:45 PM EST (21:45 UTC)
Expired
Mar 1, 2018, 1:45 AM EST
In force
9 hr
Issued by
NWS Morristown, TN
Area
Storm-based polygon
Flood severity
None

Counties Bradley County, TN, Hamilton County, TN, Marion County, TN, Sequatchie County, TN

The radar

The Northeast Alabama radar (KHTX), 81 km from the middle of the area, began a volume at 21:46 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, 9.8 hours before the alert went out and 216 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 2018-02-28Temperature 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 2018-02-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 247 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
609 m above ground
0-6 km bulk shear
62 kt
0-1 km storm-relative helicity
247 m²/s²
0-3 km storm-relative helicity
307 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 areal flood 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 areal flood warning went out at Feb 28, 3:18 PM EST, 1 hour 27 minutes earlier.

Area forecast discussion, Feb 28, 3:18 PM EST, 1 hour 27 minutes before
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Hazardous weather outlook, Feb 28, 3:46 AM EST, 12 hours 59 minutes before
Hazardous Weather Outlook
National Weather Service Morristown TN
346 AM EST Wed Feb 28 2018

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-010900-
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-
346 AM EST Wed Feb 28 2018 /246 AM CST Wed Feb 28 2018/

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

.DAY ONE...Today and Tonight

Widespread showers are expected through tonight with periods of
moderate to to locally heavy rain. A flood goes into effect for
portions of East Tennessee, Southwest North Carolina, as well as
the Cumberland Plateau this afternoon. With the ground already
soaked from the recent rains, flooding of low-lying areas, creeks,
and rivers will be possible. In response to area wide heavy rain,
some larger rivers may also rise toward flood stage by tonight.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Moderate to heavy showers will continue Thursday before ending by
evening as the flood watch will remain in effect through Thursday
evening. Continued heavy rains could result in additional flooding
of low-lying areas, creeks and rivers through Thursday evening.
As rainfall ends, some area rivers may also reach flood stage by
Thursday night.

Building high pressure Thursday night will bring strong, gusty
winds across much of the area. Higher elevations of southwest
Virginia and northeast Tennessee may see gusts in excess of 40 mph
before winds taper off during the day on Friday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 28, 11:19 AM ESTRiver Flood WarningMRXBledsoe, Marion, Sequatchie3 days
Feb 28, 11:19 AM ESTRiver Flood WarningMRXHamilton68 hr
Feb 28, 11:33 AM ESTAreal Flood AdvisoryMRXHamilton, Marion, Sequatchie3 hr

Nearby

Areal Flood Warnings in Tennessee, 2018Every areal flood 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.