Alert archive / Georgia / Special Weather Statements in 2021

Special Weather Statement, NWS Atlanta, GA

July 21, 2021Gwinnett County, Georgia

NWS Atlanta, GA issued this special weather statement at Jul 21, 2021, 9:49 PM EDT for Gwinnett County, Georgia. It was in force for 41 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 21, 2021, 9:49 PM EDT (01:49 UTC)
Expired
Jul 21, 2021, 10:30 PM EDT
In force
41 min
Issued by
NWS Atlanta, GA

County Gwinnett County, GA

The radar

The Atlanta radar (KFFC), 84 km from the middle of the area, began a volume at 01:49 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.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 1.8 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 00:00Z on 2021-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 460 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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 2021-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 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
460 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
951 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
6 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

191 
WWUS82 KFFC 220149
SPSFFC

Special Weather Statement
National Weather Service Peachtree City GA
949 PM EDT Wed Jul 21 2021
 
GAZ034-047-220230-
Walton GA-Gwinnett GA-
949 PM EDT Wed Jul 21 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN WALTON AND
SOUTHEASTERN GWINNETT COUNTIES UNTIL 1030 PM EDT...

At 948 PM EDT...a strong thunderstorm was over Loganville, or 8 miles
southeast of Lawrenceville...moving southeast at 5 mph.

  HAZARD...Heavy rain.

  IMPACT...Heavy rain may cause temporary street flooding especially 
           in poor drainage areas.

Some locations in the path of this storm include
Lawrenceville, Monroe, Snellville, Loganville, Dacula, Grayson,
Between, Bold Springs, Windsor, Harbin and Rosebud.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should slow down and be prepared for possible loss of
control due to hydroplaning.

LAT...LON 3399 8389 3382 8371 3377 8396 3379 8399
      3400 8408
TIME...MOT...LOC 0148Z 324DEG 5KT 3385 8391 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 10:21 PM EDTFlash Flood WarningFFCGwinnett, Walton6 hr
Jul 22, 12:29 AM EDTRiver Flood WarningFFCGwinnett107 min
Jul 22, 4:24 PM EDTSpecial Weather StatementFFCCrisp36 min
Jul 22, 5:50 PM EDTSpecial Weather StatementFFCMacon25 min
Jul 22, 5:59 PM EDTSpecial Weather StatementFFCBleckley31 min
Jul 22, 6:05 PM EDTSpecial Weather StatementFFCMarion, Schley25 min
Jul 22, 7:06 PM EDTSpecial Weather StatementFFCStewart24 min
Jul 22, 7:44 PM EDTFlash Flood WarningFFCStewart3 hr
Jul 22, 7:57 PM EDTSpecial Weather StatementFFCWashington33 min

Nearby

Special Weather Statements in Georgia, 2021Every special weather statement in 2021

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; radar from the NEXRAD Level II archive.