Alert archive / Tennessee / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 283, NWS Atlanta, GA

August 20, 1990Hamilton County, Tennessee

NWS Atlanta, GA issued this severe thunderstorm warning at Aug 20, 1990, 3:01 PM EDT for Hamilton County, Tennessee. It was in force for 59 min.

The area

The counties it named.

The facts

Issued
Aug 20, 1990, 3:01 PM EDT (19:01 UTC)
Expired
Aug 20, 1990, 4:00 PM EDT
In force
59 min
Issued by
NWS Atlanta, GA
Area
Whole counties

County Hamilton County, TN

The radar

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

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 7.0 hours before the alert went out and 167 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 201903
SVRCHA
TNC065-202000-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHATTANOOGA TENNESSEE
301 PM EDT MON AUG 20 1990
 
THE NATIONAL WEATHER SERVICE IN CHATTANOOGA TENNESSEE HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  400 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS
 
IN SOUTHEAST TENNESSEE
 
   ...HAMILTON COUNTY
 
AT 300 PM EDT THE CHATTANOOGA WEATHER RADAR INDICATED A SEVERE
THUNDERSTORM IN NORTHERN HAMILTON COUNTY NEAR THE COMMUNITY OF
BIRCHWOOD.
 
THE STORM IS MOVING SLOWLY TO THE SOUTH AND THERE MAY BE
SOME MINOR FLOODING DUE TO THE HEAVY RAINFALL.
 
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN.
FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR
OF YOUR HOME OR BUSINESS.  HEAVY RAINS FLOOD ROADS QUICKLY SO
DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.

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, 1:27 PM EDT, 1 hour 34 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, 1:30 PM EDT, 1 hour 31 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, 1:43 PM EDTSevere Thunderstorm WarningFFCBledsoe62 min
Aug 20, 3:20 PM EDTSevere Thunderstorm WarningFFCMarion55 min
Aug 20, 3:59 PM EDTSevere 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; the sounding from the Mesonet's radiosonde archive.