Alert archive / Georgia / Flash Flood Warnings in 2020

Flash Flood Warning 27, NWS Atlanta, GA

July 9, 2020Cobb County, Fulton County, Georgia

NWS Atlanta, GA issued this flash flood warning at Jul 9, 2020, 6:37 PM EDT for Cobb County, Fulton County, Georgia. It was in force for 6 hr. 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 9, 2020, 6:37 PM EDT (22:37 UTC)
Expired: Jul 10, 2020, 12:45 AM EDT
In force: 6 hr
Issued by: NWS Atlanta, GA
Area: Storm-based polygon
Flood severity: None

Counties Cobb County, GA, Fulton County, GA

The radar

The Atlanta radar (KFFC), 47 km from the middle of the area, began a volume at 22:39 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 12:00Z, 10.6 hours before the alert went out and 46 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 291 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 798 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: 2 m²/s²
0-3 km storm-relative helicity: -2 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

006 
WGUS52 KFFC 092237
FFWFFC
GAC067-121-100445-
/O.NEW.KFFC.FF.W.0027.200709T2237Z-200710T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Peachtree City GA
637 PM EDT Thu Jul 9 2020

The National Weather Service in Peachtree City has issued a

* Flash Flood Warning for...
  Southeastern Cobb County in north central Georgia...
  Central Fulton County in north central Georgia...

* Until 1245 AM EDT Friday.

* At 637 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Flash flooding is ongoing or 
  expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Atlanta, Smyrna, Bankhead, Bolton, Six Flags Over Georgia, 
  Mableton and Vinings.

1 to 2 inches of rain has already fallen in this area in the last 
hour.

LAT...LON 3375 8458 3381 8459 3385 8454 3386 8448
      3380 8440 3374 8444 3372 8452

FLASH FLOOD...RADAR INDICATED

$$

DJN

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 8, 8:03 PM EDT	Special Weather Statement	FFC	Taylor	27 min
Jul 8, 8:20 PM EDT	Special Weather Statement	FFC	Fannin, Union	25 min
Jul 8, 8:22 PM EDT	Severe Thunderstorm Warning	FFC	Gwinnett	23 min
Jul 8, 8:43 PM EDT	Special Weather Statement	FFC	Taylor	32 min
Jul 8, 8:56 PM EDT	Special Weather Statement	FFC	Fannin, Gilmer	34 min
Jul 8, 9:22 PM EDT	Special Weather Statement	FFC	Forsyth	23 min
Jul 9, 4:17 PM EDT	Special Weather Statement	FFC	White	28 min
Jul 9, 4:36 PM EDT	Severe Thunderstorm Warning	FFC	Union	28 min
Jul 9, 4:42 PM EDT	Severe Thunderstorm Warning	FFC	Pickens	33 min
Jul 9, 4:45 PM EDT	Special Weather Statement	FFC	Whitfield	30 min
Jul 9, 5:21 PM EDT	Special Weather Statement	FFC	Hall	24 min
Jul 9, 5:26 PM EDT	Special Weather Statement	FFC	Forsyth	34 min
Jul 9, 5:44 PM EDT	Severe Thunderstorm Warning	FFC	Gilmer	31 min
Jul 9, 5:50 PM EDT	Special Weather Statement	FFC	Fulton	25 min
Jul 9, 6:13 PM EDT	Special Weather Statement	FFC	Gwinnett	32 min
Jul 9, 6:20 PM EDT	Special Weather Statement	FFC	Fulton	25 min
Jul 9, 6:46 PM EDT	Severe Thunderstorm Warning	FFC	Clayton, Fayette, Fulton	44 min
Jul 9, 6:51 PM EDT	Special Weather Statement	FFC	Gwinnett	24 min
Jul 9, 6:56 PM EDT	Severe Thunderstorm Warning	FFC	DeKalb, Gwinnett	34 min
Jul 9, 7:24 PM EDT	Special Weather Statement	FFC	Cobb	36 min
Jul 9, 7:30 PM EDT	Severe Thunderstorm Warning	FFC	DeKalb, Gwinnett, Rockdale	30 min
Jul 9, 7:53 PM EDT	Special Weather Statement	FFC	Pike, Upson	37 min

Nearby

Flash Flood Warnings in Georgia, 2020 Every flash flood warning in 2020

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.