Alert archive / Tennessee / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 48, NWS Morristown, TN

May 6, 1999Polk County, Tennessee

NWS Morristown, TN issued this severe thunderstorm warning at May 6, 1999, 2:38 AM EDT for Polk County, Tennessee. It was in force for 32 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
May 6, 1999, 2:38 AM EDT (06:38 UTC)
Expired
May 6, 1999, 3:10 AM EDT
In force
32 min
Issued by
NWS Morristown, TN
Area
Whole counties

County Polk County, TN

The radar

The Northeast Alabama radar (KHTX), 144 km from the middle of the area, began a volume at 06:37 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.

What was reported inside it

TimeReportWhereRemark
May 6, 3:00 AM EDTThunderstorm WindReliance, TNTrees down on Highway 30.

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 5, 10:30 PM EDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 6.6 hours before the alert went out and 195 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 00:00Z on 1999-05-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 645 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, Peachtre/Fal Fld, GA at 00:00Z on 1999-05-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 280 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
645 J/kg
Mixed-layer CIN
-78 J/kg
Mixed-layer LCL
702 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
280 m²/s²
0-3 km storm-relative helicity
335 m²/s²
Significant tornado parameter
1.0
Supercell composite
9.1

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 May 6, 2:18 AM EDT, 20 minutes earlier.

Area forecast discussion, May 6, 2:18 AM EDT, 20 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
218 AM EDT THU MAY 6 1999

LINE OF THUNDERSTORMS MAINTAINING INTENSITY AS THEY MOVE ACROSS OUR
CWA THIS MORNING.  SURFACE LOW OVER NORTHEAST ND WITH A COLD FRONT
EXTENDING ACROSS EAST MO AND INTO EASTERN AR AND LA.

MODELS IN FAIRLY GOOD AGREEMENT IN MOVING 500 MB TROF.  NGM AND AVN
REASONABLY CLOSE IN TIMING OF COLD FRONT WHILE ETA IS SLOWER. PREFER
THE NGM/AVN SOLUTION.  RECOMMEND KEEPING LIKELY POPS IN FOR TODAY
AS COLD FRONT JUST ENTERING CWA BY 18Z.  PROBABLY SEE MORE
THUNDERSTORMS DEVELOP AHEAD OF FRONT THIS AFTERNOON.  LOW LEVEL JET
REMAINS TO SOUTH AND EAST OF OUR CWA AFTER 18Z...PROBABLY WONT SEE
STORMS AS STRONG THIS AFTERNOON IN OUR AREA.  STORMS LATER TODAY
SHOULD MOVE QUICKLY...SO FLOODING SHOULD NOT BE A PROBLEM WITH THE
ADDITIONAL RAIN.  UPPER LOW EXPECTED TO STALL NEAR GREAT LAKES
TONIGHT AND FRIDAY SO CHANCE POPS STILL NEEDED THROUGH THE REST OF
THE PERIOD.

THE FOLLOWING IS PRELIMINARY GUIDANCE FOR COORDINATION ONLY.

CHA TB 079/059 079/058 080 21633
TYS TB 078/058 078/057 079 21633
TRI TB 077/056 077/055 078 21633
OQT TB 078/058 078/057 079 21633

GH

In the hours before

Special weather statement, May 5, 11:23 PM EDT, 3 hours 15 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
May 5, 11:43 PM EDTSevere Thunderstorm WarningMRXBledsoe, Sequatchie47 min
May 5, 11:43 PM EDTSevere Thunderstorm WarningMRXMarion47 min
May 5, 11:58 PM EDTSevere Thunderstorm WarningMRXMorgan, Roane62 min
May 6, 12:23 AM EDTSevere Thunderstorm WarningMRXBlount, Knox, Loudon62 min
May 6, 12:23 AM EDTSevere Thunderstorm WarningMRXHamilton, Meigs, Rhea62 min
May 6, 12:30 AM EDTSevere Thunderstorm WarningMRXScott65 min
May 6, 12:31 AM EDTSevere Thunderstorm WarningMRXMarion19 min
May 6, 12:39 AM EDTSevere Thunderstorm WarningMRXAnderson, Campbell61 min
May 6, 12:49 AM EDTSevere Thunderstorm WarningMRXMarion31 min
May 6, 12:56 AM EDTSevere Thunderstorm WarningMRXBradley, McMinn, Monroe64 min
May 6, 1:15 AM EDTSevere Thunderstorm WarningMRXClaiborne, Union60 min
May 6, 1:15 AM EDTSevere Thunderstorm WarningMRXBlount, Knox60 min
May 6, 1:22 AM EDTSevere Thunderstorm WarningMRXSevier63 min
May 6, 1:26 AM EDTSevere Thunderstorm WarningMRXHamilton34 min
May 6, 1:37 AM EDTSevere Thunderstorm WarningMRXPolk63 min
May 6, 1:38 AM EDTSevere Thunderstorm WarningMRXGrainger, Hamblen, Jefferson62 min
May 6, 1:56 AM EDTSevere Thunderstorm WarningMRXBradley49 min
May 6, 1:56 AM EDTSevere Thunderstorm WarningMRXMonroe49 min
May 6, 9:06 AM EDTFlash Flood WarningMRXSevier6 hr
May 6, 1:08 AM EDTSevere Thunderstorm WarningMRXCherokee62 min
May 6, 4:19 AM EDTSevere Thunderstorm WarningMRXClay31 min

Nearby

Severe Thunderstorm Warnings in Tennessee, 1999Every severe thunderstorm warning in 1999

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.