Alert archive / Tennessee / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 284, NWS Atlanta, GA

August 20, 1990Marion County, Tennessee

NWS Atlanta, GA issued this severe thunderstorm warning at Aug 20, 1990, 2:20 PM CDT for Marion County, Tennessee. It was in force for 55 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
Aug 20, 1990, 2:20 PM CDT (19:20 UTC)
Expired
Aug 20, 1990, 3:15 PM CDT
In force
55 min
Issued by
NWS Atlanta, GA
Area
Whole counties

County Marion 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
Aug 20, 2:45 PM CDTHail 0.75Marion, 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 12:00Z, 7.3 hours before the alert went out and 142 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 12:00Z on 1990-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1775 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 12:00Z on 1990-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 square meters per square second.1939Sfc1 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
1775 J/kg
Mixed-layer CIN
-68 J/kg
Mixed-layer LCL
1373 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
41 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KCHA 201926 COR
SVRCHA
TNC115-202015-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHATTANOOGA TENNESSEE
320 PM EDT (220 PM CDT) MON AUG 20 1990

THE NATIONAL WEATHER SERVICE IN CHATTANOOGA TENNESSEE HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  415 PM EDT (315 PM CDT)
FOR PEOPLE IN THE FOLLOWING LOCATIONS

IN SOUTHEAST TENNESSEE

   ...MARION COUNTY

AT 318 PM EDT THE CHATTANOOGA WEATHER RADAR INDICATED A SEVERE
THUNDERSTORM IN MARION COUNTY NEAR JASPER.

THE STORM IS MOVING SLOWLY TO THE SOUTH AND DUE THE THE HEAVY
RAINFALL WITH THIS THUNDERSTORM...SOME FLOODING MAY OCCUR.


WHEN THUNDERSTORMS ARE OCCURRING...PEOPLE SHOULD MOVE INSIDE A
STRONG BUILDING.  DO NOT STAND BY WINDOWS.  DON'T USE TELEPHONES
OR ELECTRICAL APPLIANCES UNLESS IN AN EMERGENCY UNTIL THE STORM
HAS PASSED.  MOTORISTS SHOULD NOT DRIVE INTO LOW WATER CROSSINGS.

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, Aug 20, 12:27 PM CDT, 1 hour 53 minutes before
GAZ006-008-009-202200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MACON GA
130 PM EDT MON AUG 20 1990

      ...HEAT INDICES OF 105 TO 110 IN CENTRAL GEORGIA...

AT 130 PM TEMPERATURES IN THE CENTRAL PART OF THE STATE WERE IN
THE MID 90 DEGREE RANGE. THIS TEMPRATURE COMBINED WITH THE RELATIVE
HUMIDITY WAS GIVING A HEAT INDEX OF 105 IN MACON AND 108 IN WARNER
ROBINS. WITH THE TEMPERATURE IN MIDDLE GEORGIA EXPECTED TO CLIMB
TO AROUND 100 DEGREES THIS AFTERNOON BETWEEN 3 AND 5 MPH...THE HEAT
INDEX COULD EVEN GO ABOVE 110.

IF YOU HAVE TO BE OUTSIDE WORKING THIS AFTERNOON...BE EXTREMELY
CAREFUL. TAKE FREQUENT BREAKS...AND DRINK A LOT OF WATER. THESE
CONDITIONS CAN BE VERY DANGEROUS. HEAT EXHUASTION AND SUNSTROKE
ARE POSSIBLE.
Special weather statement, Aug 20, 12:30 PM CDT, 1 hour 50 minutes before
GAZ006-008-009-202200-

SPECIAL WEATHER STATEMENT...CORRECTION
NATIONAL WEATHER SERVICE MACON GA
130 PM EDT MON AUG 20 1990

      ...HEAT INDICES OF 105 TO 110 IN CENTRAL GEORGIA...

AT 130 PM TEMPERATURES IN THE CENTRAL PART OF THE STATE WERE IN
THE MID 90 DEGREE RANGE. THIS TEMPERATURE COMBINED WITH THE RELATIVE
HUMIDITY WAS GIVING A HEAT INDEX OF 105 IN MACON AND 108 IN WARNER
ROBINS. WITH THE TEMPERATURE IN MIDDLE GEORGIA EXPECTED TO CLIMB
TO AROUND 100 DEGREES THIS AFTERNOON BETWEEN 3 AND 5 PM...THE HEAT
INDEX COULD EVEN GO ABOVE 110.

IF YOU HAVE TO BE OUTSIDE WORKING THIS AFTERNOON...BE EXTREMELY
CAREFUL. TAKE FREQUENT BREAKS...AND DRINK A LOT OF WATER. THESE
CONDITIONS CAN BE VERY DANGEROUS. HEAT EXHUASTION AND SUNSTROKE
ARE POSSIBLE.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 12:43 PM CDTSevere Thunderstorm WarningFFCBledsoe62 min
Aug 20, 2:01 PM CDTSevere Thunderstorm WarningFFCHamilton59 min
Aug 20, 2:59 PM CDTSevere Thunderstorm WarningFFCHamilton61 min

Nearby

Severe Thunderstorm Warnings in Tennessee, 1990Every severe thunderstorm warning in 1990

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.