Alert archive / Tennessee / Severe Thunderstorm Warnings in 1989

Severe Thunderstorm Warning 69, NWS Atlanta, GA

May 20, 1989Bradley County, Hamilton County, Tennessee

NWS Atlanta, GA issued this severe thunderstorm warning at May 20, 1989, 6:29 AM EDT for Bradley County, Hamilton County, Tennessee. It was in force for 61 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 20, 1989, 6:29 AM EDT (10:29 UTC)
Expired
May 20, 1989, 7:30 AM EDT
In force
61 min
Issued by
NWS Atlanta, GA
Area
Whole counties

Counties Bradley County, TN, Hamilton County, TN

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

What was reported inside it

TimeReportWhereRemark
May 20, 6:30 AM EDTThunderstorm Wind 0Hamilton, TN

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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 10.5 hours before the alert went out and 179 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 1989-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 999 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 1989-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 210 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
999 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
1198 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
210 m²/s²
0-3 km storm-relative helicity
414 m²/s²
Significant tornado parameter
1.4
Supercell composite
6.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KCHA 201032
SVRCHA
TNC011-065-201130-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHATTANOOGA TN
629 AM EDT SAT MAY 20 1989
 
THE NATIONAL WEATHER SERVICE IN CHATTANOOGA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  730 AM EDT
FOR PEOPLE IN THE FOLLOWING COUNTIES...
 
IN SOUTHEAST TENNESSEE
          ...BRADLEY...SOUTHERN HAMILTON
 
THUNDERSTORMS WERE INDICATED BY RADAR MOVING SOUTHEAST INTO SOUTHERN
HAMILTON AND INTO BRADLEY COUNTIES. HIGH WINDS HAVE BEEN
REPORTED ALONG WITH CONTINUOUS LIGHTNING.
 
 
THIS IS A DANGEROUS STORM.  IF YOU ARE IN ITS PATH YOU SHOULD
PREPARE FOR DAMAGING WIND IN EXCESS OF 55 MPH...LARGE HAIL...AND
DEADLY LIGHTNING.  PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT STAY AWAY FROM WINDOWS.

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.

In the hours before

Special weather statement, May 20, 6:24 AM EDT, 5 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ATLANTA GA
625 AM EDT SAT MAY 20 1989

AT 620 AM EDT RADAR SHOWED A LINE OF THUNDERSTORMS JUST NORTH OF THE
TENNESSEE-GEORGIA BORDER NEAR CHATTANOOGA. THE LINE WAS MOVING SOUTH NEAR
25 MPH.

THESE THUNDERSTORMS HAVE BEEN ACCOMPANIED BY HIGH WINDS WHICH HAVE BLOWN
DOWN TREES IN VANBUREN COUNTY IN TENNESSEE.

THESE THUNDERSTORMS MAY BE ACCOMPANIED BY HIGH WINDS TO 40 MPH...SMALL HAIL
...FREQUENT LIGHTNING AND BRIEF HEAVY DOWMPOURS.

THESE THUNDERSTORMS WILL MOVE INTO EXTREME NORTHWEST GEORGIA BY
700 AM AND CONTINUE SOUTHEASTWARD INTO DADE...WALKER...WHITEFIELD...MURRAY
COUNTIES.

PERSONS IN THE PATH OF THESE THUNDERSTORMS SHOULD STAY ALERT AS THESE
STORMS APPROACH AND TAKE SHELTER IMMEDIATELY.

The office that day

Everything else NWS Atlanta, GA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 20, 5:26 AM EDTSevere Thunderstorm WarningFFCBledsoe, Van Buren64 min
May 20, 6:08 AM EDTSevere Thunderstorm WarningFFCHamilton, Rhea52 min

Nearby

Severe Thunderstorm Warnings in Tennessee, 1989Every severe thunderstorm warning in 1989

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.