Alert archive / Georgia / Flash Flood Warnings in 2021

Flash Flood Warning 31, NWS Atlanta, GA

September 7, 20214 counties in Georgia

NWS Atlanta, GA issued this flash flood warning at Sep 7, 2021, 11:47 PM EDT for 4 counties in Georgia. It was in force for 9 hr. 9 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Sep 7, 2021, 11:47 PM EDT (03:47 UTC)
Expired
Sep 8, 2021, 9:00 AM EDT
In force
9 hr
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

Counties Cobb County, GA, Forsyth County, GA, Fulton County, GA, Gwinnett County, GA

The radar

The Atlanta radar (KFFC), 76 km from the middle of the area, began a volume at 03:48 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.

What was reported inside it

TimeReportWhereRemark
Sep 7, 11:58 PM EDTFLASH FLOOD2 S Alpharetta, GAWATER COVERING ROADWAY WITH A STALLED VEHICLE AT ENCORE PARKWAY AT NORTH POINT CENTER EAST.
Sep 8, 12:08 AM EDTFLASH FLOOD1 Sse Alpharetta, GAWATER COVERING THE ROAD WITH STALLED VEHICLE AT HAYNES BRIDGE ROAD AND WESTSIDE PARKWAY.
Sep 8, 12:30 AM EDTFLASH FLOOD2 Ene White Water Park, GAPORTION OF EAST LAKE PARKWAY WASHED AWAY ABOVE DRAINAGE PIPE LEAVING SEVERAL FOOT WIDE AND DEEP HOLE.
Sep 8, 2:00 AM EDTFLASH FLOOD1 Nnw White Water Park, GAFLASH FLOODING ALONG SOPE CREEK HAS LEAD TO A COMPLETE COLLAPSE OF PICKENS INDUSTRIAL DR OVER THE CREEK.
Sep 8, 2:00 AM EDTFLASH FLOOD1 Sw Marietta, GAFLASH FLOODING OF SMALL CREEK BEHIND HOME DESTROYED A SMALL FOOT BRIDGE WELL ABOVE NORMAL DRAINAGE BASIN USED BY THE HOMEOWNERS NEAR THE INTERSECTION OF CHINQUAPIN DR AND S WOODLAND DR SW.
Sep 8, 4:00 AM EDTFLASH FLOOD2 Ene Dobbins Air Reser, GANUMEROUS CARS FLOODED IN THE PARKING LOT OF THE MARIETTA CROSSING APARTMENT HOMES, LIKELY DUE TO FLASH FLOODING OF NEARBY CREEK.
Sep 8, 4:00 AM EDTFLASH FLOOD3 W Sandy Springs, GAFLASH FLOODING ALL ALONG COLUMNS DR. SE, ESPECIALLY NOTED WHERE THE CHATTAHOOCHEE AND SOPE CREEK MEET. WATER IN THE ROADWAY, SEVERAL STALLED VEHICLES, AND WATER REPORTED UP TO SEVERAL INCHES DEEP IN SOME BASEMENTS.
Sep 8, 6:00 AM EDTFLOOD1 Sw Roswell, GARIVER FLOODING IS COVERING THE INTERSECTION OF WILLEO RD AND AZALEA DR, MAKING IT IMPASSIBLE FOR VEHICLE TRAFFIC.
Sep 8, 6:00 AM EDTFLOOD2 Ese Roswell, GAFLOODING OVER THE ROADWAY OF RIVERSIDE RD ALONG THE CHATTAHOOCHEE RIVER.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 3.8 hours before the alert went out and 73 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 2021-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2587 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 2021-09-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 43 square meters per square second.193958Sfc1 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
2587 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
936 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

892 
WGUS52 KFFC 080347
FFWFFC
GAC067-117-121-135-081000-
/O.NEW.KFFC.FF.W.0031.210908T0347Z-210908T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Peachtree City GA
1147 PM EDT Tue Sep 7 2021

The National Weather Service in Peachtree City has issued a

* Flash Flood Warning for...
  Northeastern Cobb County in north central Georgia...
  Southwestern Forsyth County in north central Georgia...
  Northeastern Fulton County in north central Georgia...
  Northwestern Gwinnett County in north central Georgia...

* Until 600 AM EDT Wednesday.

* At 1147 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Marietta, Sandy Springs, Roswell, Johns Creek, Alpharetta, Smyrna, 
  Dunwoody, Duluth, Sugar Hill, Suwanee, Buford, Berkeley Lake, Fair 
  Oaks, Mountain Park, Mount Bethel, Brookwood, Sandy Plains, White 
  Water Park, Dobbins Air Reserve Base and Buford Dam-Lake Lanier 
  Parks.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3390 8459 3394 8461 3400 8454 3409 8439
      3410 8424 3416 8410 3415 8401 3409 8401
      3402 8405 3397 8416 3396 8427 3397 8434
      3388 8448

FLASH FLOOD...RADAR INDICATED

$$
2 follow-up statements
824 
WGUS52 KFFC 080616
FFWFFC
GAC067-117-121-135-081300-
/O.EXT.KFFC.FF.W.0031.000000T0000Z-210908T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Peachtree City GA
216 AM EDT Wed Sep 8 2021

The National Weather Service in Peachtree City has extended the

* Flash Flood Warning for...
  Northeastern Cobb County in north central Georgia...
  Southwestern Forsyth County in north central Georgia...
  Northeastern Fulton County in north central Georgia...
  Northwestern Gwinnett County in north central Georgia...

* Until 900 AM EDT Wednesday.

* At 216 AM EDT, local law enforcement reported numerous impassable 
  roadways and some flooding of residences from previous heavy rain 
  across the warned area. Between 3 and 5 inches of rain have 
  fallen. Flash flooding is already occurring.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Law enforcement reported.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Marietta, Sandy Springs, Roswell, Johns Creek, Alpharetta, Smyrna, 
  Dunwoody, Duluth, Sugar Hill, Suwanee, Buford, Berkeley Lake, Fair 
  Oaks, Mountain Park, Mount Bethel, Brookwood, Sandy Plains, White 
  Water Park, Dobbins Air Reserve Base and Buford Dam-Lake Lanier 
  Parks.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3390 8459 3394 8461 3400 8454 3409 8439
      3410 8424 3416 8410 3415 8401 3409 8401
      3402 8405 3397 8416 3396 8427 3397 8434
      3388 8448

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$
371 
WGUS72 KFFC 081258
FFSFFC

Flash Flood Statement
National Weather Service Peachtree City GA
858 AM EDT Wed Sep 8 2021

GAC067-117-121-135-081308-
/O.EXP.KFFC.FF.W.0031.000000T0000Z-210908T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cobb GA-Forsyth GA-Fulton GA-Gwinnett GA-
858 AM EDT Wed Sep 8 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 9 AM EDT THIS MORNING FOR 
NORTHEASTERN COBB, SOUTHWESTERN FORSYTH, NORTHEASTERN FULTON AND 
NORTHWESTERN GWINNETT COUNTIES...

The threat for flash flooding has ended, but there continues to be a 
response in creeks, streams, and rivers. Be sure to heed all road 
closures, and do not drive through flooded roadways.

LAT...LON 3390 8459 3394 8461 3400 8454 3409 8439
      3410 8424 3416 8410 3415 8401 3409 8401
      3402 8405 3397 8416 3396 8427 3397 8434
      3388 8448

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 7, 8:20 PM EDTSpecial Weather StatementFFCCoweta, Heard25 min
Sep 7, 8:34 PM EDTSpecial Weather StatementFFCTroup26 min
Sep 7, 8:36 PM EDTSpecial Weather StatementFFCPolk39 min
Sep 7, 9:11 PM EDTFlash Flood WarningFFCHaralson, Polk6 hr
Sep 7, 9:23 PM EDTSpecial Weather StatementFFCMeriwether, Pike52 min
Sep 7, 10:02 PM EDTSpecial Weather StatementFFCCoweta, Fayette43 min
Sep 7, 10:38 PM EDTSpecial Weather StatementFFCForsyth52 min
Sep 7, 10:49 PM EDTSpecial Weather StatementFFCClayton, Fayette41 min
Sep 7, 11:06 PM EDTSevere Thunderstorm WarningFFCClayton, Cobb, Douglas, Fulton24 min
Sep 7, 11:34 PM EDTSevere Thunderstorm WarningFFCCobb, DeKalb, Fulton26 min
Sep 8, 12:04 AM EDTSpecial Weather StatementFFCGwinnett26 min
Sep 8, 12:37 AM EDTSpecial Weather StatementFFCForsyth23 min
Sep 8, 12:55 AM EDTRiver Flood WarningFFCForsyth, Fulton38 hr
Sep 8, 1:01 AM EDTRiver Flood WarningFFCCobb7 hr
Sep 8, 1:08 AM EDTRiver Flood WarningFFCCobb4 hr
Sep 8, 1:13 AM EDTRiver Flood WarningFFCFulton, Gwinnett4 hr
Sep 8, 1:24 AM EDTRiver Flood WarningFFCForsyth4 hr
Sep 8, 1:46 AM EDTRiver Flood WarningFFCCobb4 hr
Sep 8, 1:51 AM EDTRiver Flood WarningFFCFulton7 hr
Sep 8, 5:31 AM EDTRiver Flood WarningFFCCobb, Fulton8 hr
Sep 8, 5:33 AM EDTRiver Flood WarningFFCCobb, Fulton10 hr
Sep 8, 5:38 AM EDTRiver Flood WarningFFCCobb, Fulton5 hr
Sep 8, 1:04 PM EDTSpecial Weather StatementFFCWarren26 min
Sep 8, 1:30 PM EDTSpecial Weather StatementFFCWarren30 min
Sep 8, 2:03 PM EDTSpecial Weather StatementFFCTaliaferro27 min
Sep 8, 2:17 PM EDTSpecial Weather StatementFFCWhitfield28 min
Sep 8, 2:47 PM EDTSpecial Weather StatementFFCHancock, Jasper, Putnam, Taliaferro, Warren43 min
Sep 8, 3:22 PM EDTSpecial Weather StatementFFCLamar, Meriwether, Pike, Spalding, Upson38 min
Sep 8, 3:56 PM EDTSpecial Weather StatementFFCLamar, Meriwether, Pike49 min
Sep 8, 4:15 PM EDTSpecial Weather StatementFFCBaldwin, Hancock, Jones45 min
Sep 8, 4:25 PM EDTSpecial Weather StatementFFCChattooga50 min
Sep 8, 5:10 PM EDTSpecial Weather StatementFFCCarroll50 min
Sep 8, 5:13 PM EDTSpecial Weather StatementFFCUnion47 min
Sep 8, 5:17 PM EDTSpecial Weather StatementFFCBarrow, Clarke, Gwinnett, Jackson, Madison43 min
Sep 8, 5:28 PM EDTSpecial Weather StatementFFCJefferson, Washington47 min
Sep 8, 5:32 PM EDTSpecial Weather StatementFFCFloyd43 min
Sep 8, 6:05 PM EDTSpecial Weather StatementFFCBarrow, Forsyth, Jackson55 min
Sep 8, 6:08 PM EDTSpecial Weather StatementFFCGilmer, Pickens52 min
Sep 8, 6:16 PM EDTFlash Flood WarningFFCBarrow, Forsyth, Fulton, Gwinnett, Hall, Jackson6 hr
Sep 8, 6:57 PM EDTSpecial Weather StatementFFCDawson, Lumpkin, Pickens48 min
Sep 8, 7:23 PM EDTRiver Flood WarningFFCForsyth117 min
Sep 8, 7:44 PM EDTSpecial Weather StatementFFCCherokee, Dawson, Forsyth, Lumpkin46 min

Nearby

Flash Flood Warnings in Georgia, 2021Every flash flood warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.