Alert archive / Georgia / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 686, NWS Atlanta, GA

September 21, 1999Gwinnett County, Georgia

NWS Atlanta, GA issued this severe thunderstorm warning at Sep 21, 1999, 2:57 PM EDT for Gwinnett County, Georgia. It was in force for 33 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 21, 1999, 2:57 PM EDT (18:57 UTC)
Expired
Sep 21, 1999, 3:30 PM EDT
In force
33 min
Issued by
NWS Atlanta, GA
Area
Whole counties

County Gwinnett County, GA

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 7.0 hours before the alert went out and 79 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 12:00Z on 1999-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 230 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 12:00Z on 1999-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -11 square meters per square second.1939587897117136Sfc1 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
230 J/kg
Mixed-layer CIN
-45 J/kg
Mixed-layer LCL
557 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
-11 m²/s²
0-3 km storm-relative helicity
42 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 KATL 211859 RRA
SVRATL
GAC135-211930-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
257 PM EDT TUE SEP 21 1999

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  GWINNETT COUNTY IN NORTHWESTERN GEORGIA

* UNTIL 330 PM EDT.

* AT 256 PM EDT... PUBLIC REPORTED TREES DOWN NEAR NORCROSS.
  THIS STORM WAS MOVING SOUTHEAST AT 25 MPH.

* SOME LOCATIONS IN OR NEAR THE PATH OF THIS STORM ARE...
  LILBURN...
  LAWRENCEVILLE...
  SNELLVILLE...
  GRAYSON...

DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN AND DEADLY LIGHTNING
ARE ALL POSSIBLE IN SEVERE THUNDERSTORMS. IF YOU SEE DAMAGE OR
LARGE HAIL...CAL>L THE NATIONAL WEATHER SERVICE AT 770-486-1133 AT
EXTENSION 2 0 4.

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, Sep 21, 12:58 PM EDT, 1 hour 59 minutes before
GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
091>098-103>113-211900-

NORTH AND CENTRAL GEORGIA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1258 PM EDT TUE SEP 21 1999

A FEW SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON OVER
NORTH GEORGIA. THIS INCLUDES THE ATLANTA AND ATHENS AREAS AND
LOCATIONS NORTH.

A LINE OF STRONG THUNDERSTORMS...AHEAD OF A COLD FRONT IN NORTHWEST
GEORGIA EARLY THIS AFTERNOON...WILL MOVE EAST AT 10 TO 15 MILES PER
HOUR. THE ATMOSPHERE OVER NORTH GEORGIA WILL BECOME INCREASINGLY
UNSTABLE DURING THE AFTERNOON AS COLD AIR ALOFT MOVES OVER THE
WARM MOIST AIR NEAR THE SURFACE. AS A RESULT...A FEW THUNDERSTORMS
COULD PRODUCE LARGE HAIL EQUAL TO OR GREATER THAN DIME SIZE.

SPOTTERS AND EMERGENCY MANAGERS IN NORTH GEORGIA SHOULD BE
PREPARED FOR POSSIBLE ACTIVATION.
Special weather statement, Sep 21, 12:58 PM EDT, 1 hour 59 minutes before
GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
091>098-103>113-211900-

NORTH AND CENTRAL GEORGIA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1258 PM EDT TUE SEP 21 1999

A FEW SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON OVER
NORTH GEORGIA. THIS INCLUDES THE ATLANTA AND ATHENS AREAS AND
LOCATIONS NORTH.

A LINE OF STRONG THUNDERSTORMS...AHEAD OF A COLD FRONT IN NORTHWEST
GEORGIA EARLY THIS AFTERNOON...WILL MOVE EAST AT 10 TO 15 MILES PER
HOUR. THE ATMOSPHERE OVER NORTH GEORGIA WILL BECOME INCREASINGLY
UNSTABLE DURING THE AFTERNOON AS COLD AIR ALOFT MOVES OVER THE
WARM MOIST AIR NEAR THE SURFACE. AS A RESULT...A FEW THUNDERSTORMS
COULD PRODUCE LARGE HAIL EQUAL TO OR GREATER THAN DIME SIZE.

SPOTTERS AND EMERGENCY MANAGERS IN NORTH GEORGIA SHOULD BE
PREPARED FOR POSSIBLE ACTIVATION.
Local storm report, Sep 21, 2:25 PM EDT, 32 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
225 PM EDT TUE SEP 21 1999

TIME(EDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

210 PM     MARIETTA                  GA   1.00 INCH HAIL
09/21/99   COBB                           OFF-DUTY CNN METEOROLOGIST
                                          REPORTED 1-INCH HAIL
                                          COVERING THE GROUND AND GUST
                                          TO 78 MPH WITH HAND-HELD
                                          ANEMOMETER
Local storm report, Sep 21, 2:32 PM EDT, 25 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
232 PM EDT TUE SEP 21 1999

TIME(EDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

210 PM     MARIETTA                  GA   1.00 INCH HAIL
09/21/99   COBB                           OFF-DUTY CNN METEOROLOGIST
                                          REPORTED 1-INCH HAIL
                                          COVERING THE GROUND AND GUST
                                          TO 78 MPH WITH HAND-HELD
                                          ANEMOMETER

215 PM     KENNESAW                  GA   0.75 INCH HAIL
09/21/99   COBB
Local storm report, Sep 21, 2:40 PM EDT, 17 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
240 PM EDT TUE SEP 21 1999

TIME(EDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

210 PM     MARIETTA                  GA   1.00 INCH HAIL
09/21/99   COBB                           OFF-DUTY CNN METEOROLOGIST
                                          REPORTED 1-INCH HAIL
                                          COVERING THE GROUND AND GUST
                                          TO 78 MPH WITH HAND-HELD
                                          ANEMOMETER

215 PM     KENNESAW                  GA   0.75 INCH HAIL
09/21/99   COBB

230 PM     SANDY SPRINGS             GA   1.25 INCH HAIL
09/21/99   FULTON                         COVERING THE GROUND
Local storm report, Sep 21, 2:45 PM EDT, 12 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
245 PM EDT TUE SEP 21 1999

TIME(EDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

210 PM     MARIETTA                  GA   1.00 INCH HAIL
09/21/99   COBB                           OFF-DUTY CNN METEOROLOGIST
                                          REPORTED 1-INCH HAIL
                                          COVERING THE GROUND AND GUST
                                          TO 78 MPH WITH HAND-HELD
                                          ANEMOMETER

215 PM     KENNESAW                  GA   0.75 INCH HAIL
09/21/99   COBB

230 PM     SANDY SPRINGS             GA   1.25 INCH HAIL
09/21/99   FULTON                         COVERING THE GROUND

240 PM     DUNWOODY                  GA   0.75 INCH HAIL
09/21/99   DEKALB

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 21, 2:17 PM EDTSevere Thunderstorm WarningFFCCobb33 min
Sep 21, 2:31 PM EDTSevere Thunderstorm WarningFFCDeKalb, Fulton34 min
Sep 21, 3:02 PM EDTSevere Thunderstorm WarningFFCClayton, Fulton33 min
Sep 21, 3:21 PM EDTSevere Thunderstorm WarningFFCBarrow, Hall, Jackson34 min
Sep 21, 3:30 PM EDTSevere Thunderstorm WarningFFCFayette35 min
Sep 21, 3:33 PM EDTSevere Thunderstorm WarningFFCWalton37 min
Sep 21, 4:03 PM EDTSevere Thunderstorm WarningFFCJasper, Newton32 min
Sep 21, 4:24 PM EDTSevere Thunderstorm WarningFFCClarke, Oconee36 min
Sep 21, 4:53 PM EDTSevere Thunderstorm WarningFFCPutnam32 min

Nearby

Severe Thunderstorm Warnings in Georgia, 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; the sounding from the Mesonet's radiosonde archive.