Alert archive / Tennessee / Flash Flood Warnings in 2010

Flash Flood Warning 18, NWS Morristown, TN

August 18, 20104 counties in Tennessee

NWS Morristown, TN issued this flash flood warning at Aug 18, 2010, 11:30 AM EDT for 4 counties in Tennessee. It was in force for 6 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: Aug 18, 2010, 11:30 AM EDT (15:30 UTC)
Expired: Aug 18, 2010, 5:30 PM EDT
In force: 6 hr
Issued by: NWS Morristown, TN
Area: Storm-based polygon
Flood severity: None

Counties Campbell County, TN, Claiborne County, TN, Scott County, TN, Union County, TN

The radar

The Knoxville radar (KMRX), 63 km from the middle of the area, began a volume at 15:34 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, 3.5 hours before the alert went out and 232 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: 1640 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 460 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 116 m²/s²
0-3 km storm-relative helicity: 130 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.7

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash 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 flash flood warning went out at Aug 18, 10:02 AM EDT, 1 hour 28 minutes earlier.

Area forecast discussion, Aug 18, 10:02 AM EDT, 1 hour 28 minutes before

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Hazardous weather outlook, Aug 18, 4:59 AM EDT, 6 hours 31 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MORRISTOWN TN
459 AM EDT WED AUG 18 2010

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-190900-
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-
459 AM EDT WED AUG 18 2010 /359 AM CDT WED AUG 18 2010/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST NORTH
CAROLINA...EAST TENNESSEE AND SOUTHWEST VIRGINIA.

.DAY ONE...TODAY AND TONIGHT

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL DEVELOP AND
MOVE NORTHEAST ACROSS THE AREA BY EARLY AFTERNOON. DUE TO THE EXPECTED SLOW
MOVEMENT OF THE STORMS...LOCALLY HEAVY RAINFALL WILL BE POSSIBLE...WITH
SOME FLOODING POSSIBLE IN A FEW AREAS. SINCE THERE HAS BEEN
REPEATED AREAS OF HEAVY RAINFALL THAT HAS OCCURRED IN THE PAST 24 HOURS
...A FLASH FLOOD WATCH IS IN EFFECT FOR ALL OF SOUTHWEST VIRGINIA...AND
TENNESSEE COUNTIES BORDERING KENTUCKY AND VIRGINIA FROM 2 PM EDT UNTIL
MIDNIGHT EDT TONIGHT.

RAINFALL AMOUNTS WILL RANGE FROM AN INCH TO AROUND TWO INCHES ACROSS
THE AREA...WITH SOME ISOLATED AND LOCALIZED AMOUNTS APPROACHING THREE
INCHES.

MORE HEAVY RAINFALL IS EXPECTED OVERNIGHT TONIGHT...WHICH MAY RESULT
IN FURTHER FLASH FLOODING IN SOME AREAS IN EAST TENNESSEE AND SOUTHWEST
VIRGINIA. IF YOU APPROACH A FLOODED ROAD...TURN AROUND...DON'T DROWN.
DO NOT DRIVE THROUGH FLOODED ROADS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

A VERY MOIST AIR MASS WILL REMAIN ACROSS THE SOUTHERN APPALACHIAN
REGION THROUGHOUT THE REMAINDER OF THE WEEK...WITH SLOW-MOVING AND
SCATTERED THUNDERSTORMS PRODUCING A THREAT FOR LOCALLY HEAVY RAINFALL
EACH DAY...MAINLY DURING THE AFTERNOON AND EVENING HOURS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING DUE TO THE
POTENTIAL FOR FLASH FLOODING.

TT

In the hours before

Local storm report, Aug 18, 10:40 AM EDT, 50 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
1040 AM EDT WED AUG 18 2010

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

0800 AM     FLASH FLOOD      E TRADE                 36.35N 81.75W
08/17/2010                   JOHNSON            TN   DEPT OF HIGHWAYS

            HIGH WATER ON DUGGER HOLLOW RD, FRANK SHUPE LN, AND REECE
            RD...REPORTED BY HWY DEPT.

&&

SROBERTS

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 18, 3:08 AM EDT	Flash Flood Watch	MRX	Anderson, Bledsoe, Blount, Bradley, Campbell, Carter and 27 more	31 hr
Aug 18, 9:07 AM EDT	Areal Flood Advisory	MRX	Anderson, Campbell, Claiborne, Hancock, Morgan, Scott and 1 more	3 hr
Aug 18, 11:57 AM EDT	Areal Flood Advisory	MRX	Anderson, Knox, Morgan, Roane, Union	3 hr
Aug 18, 12:04 PM EDT	Areal Flood Advisory	MRX	Claiborne, Grainger, Hamblen, Hancock, Hawkins, Union	6 hr
Aug 18, 2:33 PM EDT	Flash Flood Warning	MRX	Anderson, Knox, Morgan, Roane, Union	6 hr

Nearby

Flash Flood Warnings in Tennessee, 2010 Every flash flood warning in 2010

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.