Alert archive / Georgia / Flash Flood Warnings in 2021

Flash Flood Warning 32, NWS Atlanta, GA

September 8, 20216 counties in Georgia

NWS Atlanta, GA issued this flash flood warning at Sep 8, 2021, 6:16 PM EDT for 6 counties in Georgia. It was in force for 6 hr. 2 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 8, 2021, 6:16 PM EDT (22:16 UTC)
Expired
Sep 9, 2021, 12:15 AM EDT
In force
6 hr
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

Counties Barrow County, GA, Forsyth County, GA, Fulton County, GA, Gwinnett County, GA, Hall County, GA, Jackson County, GA

The radar

The Atlanta radar (KFFC), 89 km from the middle of the area, began a volume at 22:17 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 8, 6:56 PM EDTFLASH FLOOD3 Ene Alpharetta, GAOVER A FOOT OF WATER COVERING THE INTERSECTION OF WINDWARD PLAZA AND WINDWARD PARKWAY IN ALPHARETTA. AT LEAST ONE STALLED VEHICLE IN THE WATER.
Sep 8, 7:05 PM EDTFLASH FLOOD1 E Alpharetta, GAWATER FLOWING OVER ACADEMY STREET. ROADWAY TEMPORARILY CLOSED AT TIME OF REPORT.

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 12:00Z, 10.3 hours before the alert went out and 86 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 2021-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 935 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 12:00Z on 2021-09-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 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
935 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
661 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
39 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

518 
WGUS52 KFFC 082216
FFWFFC
GAC013-117-121-135-139-157-090415-
/O.NEW.KFFC.FF.W.0032.210908T2216Z-210909T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Peachtree City has issued a

* Flash Flood Warning for...
  Western Barrow County in north central Georgia...
  Southwestern Forsyth County in north central Georgia...
  Northeastern Fulton County in north central Georgia...
  Northern Gwinnett County in north central Georgia...
  Southwestern Hall County in north central Georgia...
  West Central Jackson County in northeastern Georgia...

* Until 1215 AM EDT.

* At 616 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. 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...
  Lawrenceville, Winder, Cumming, Sandy Springs, Roswell, Johns 
  Creek, Alpharetta, Milton, Duluth, Sugar Hill, Suwanee, Buford, 
  Braselton, Auburn, Dacula, Berkeley Lake, Hoschton, Bethlehem, 
  Carl and Rest Haven.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to higher ground now. Act quickly to protect your life.

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

Stay away or be swept away. River banks and culverts can become 
unstable and unsafe.

&&

LAT...LON 3416 8436 3418 8404 3411 8383 3409 8365
      3394 8368 3400 8438 3406 8439 3411 8442
      3411 8440 3412 8439 3413 8436

FLASH FLOOD...RADAR INDICATED

$$
2 follow-up statements
925 
WGUS72 KFFC 090002
FFSFFC

Flash Flood Statement
National Weather Service Peachtree City GA
802 PM EDT Wed Sep 8 2021

GAC013-117-121-135-139-157-090415-
/O.CON.KFFC.FF.W.0032.000000T0000Z-210909T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Barrow GA-Forsyth GA-Fulton GA-Gwinnett GA-Hall GA-Jackson GA-
802 PM EDT Wed Sep 8 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1215 AM EDT THURSDAY 
FOR WESTERN BARROW, SOUTHWESTERN FORSYTH, NORTHEASTERN FULTON, 
NORTHERN GWINNETT, SOUTHWESTERN HALL AND WEST CENTRAL JACKSON 
COUNTIES...

At 802 PM EDT, Doppler radar indicated that thunderstorms produced 
heavy rain across the warned area earlier. Although the persistent 
heavy rain has ended, between 1.5 and 3.5 inches of rain have fallen 
over the 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...
  Lawrenceville, Winder, Cumming, Sandy Springs, Roswell, Johns 
  Creek, Alpharetta, Milton, Duluth, Sugar Hill, Suwanee, Buford, 
  Braselton, Auburn, Dacula, Berkeley Lake, Hoschton, Bethlehem, 
  Carl and Rest Haven.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

Stay away or be swept away. River banks and culverts can become 
unstable and unsafe.

&&

LAT...LON 3416 8436 3418 8404 3411 8383 3409 8365
      3394 8368 3400 8438 3406 8439 3411 8442
      3411 8440 3412 8439 3413 8436

FLASH FLOOD...RADAR INDICATED

$$
514 
WGUS72 KFFC 090200
FFSFFC

Flash Flood Statement
National Weather Service Peachtree City GA
1000 PM EDT Wed Sep 8 2021

GAC013-157-090210-
/O.CAN.KFFC.FF.W.0032.000000T0000Z-210909T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Barrow GA-Jackson GA-
1000 PM EDT Wed Sep 8 2021

...FLASH FLOOD WARNING IS CANCELLED FOR WESTERN BARROW AND WEST 
CENTRAL JACKSON COUNTIES...

Flash flooding is no longer expected to pose a threat. Please 
continue to be alert for high water on creeks and streams and heed 
any remaining road closures.

LAT...LON 3416 8436 3418 8404 3411 8383 3400 8387
      3395 8381 3400 8438 3406 8439 3411 8442
      3412 8436

$$

GAC117-121-135-139-090415-
/O.CON.KFFC.FF.W.0032.000000T0000Z-210909T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Forsyth GA-Fulton GA-Gwinnett GA-Hall GA-
1000 PM EDT Wed Sep 8 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1215 AM EDT THURSDAY 
FOR SOUTHWESTERN FORSYTH, NORTHEASTERN FULTON, NORTHERN GWINNETT AND 
SOUTHWESTERN HALL COUNTIES...

At 1000 PM EDT, Although the persistent heavy rain has ended, 
between 1.5 and 3.5 inches of rain fell over the area earlier. 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...
  Lawrenceville, Cumming, Sandy Springs, Roswell, Johns Creek, 
  Alpharetta, Milton, Duluth, Sugar Hill, Suwanee, Buford, 
  Braselton, Dacula, Berkeley Lake, Rest Haven, Brookwood, Buford 
  Dam-Lake Lanier Parks and Hog Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

Stay away or be swept away. River banks and culverts can become 
unstable and unsafe.

&&

LAT...LON 3416 8436 3418 8404 3411 8383 3400 8387
      3395 8381 3400 8438 3406 8439 3411 8442
      3412 8436

FLASH FLOOD...RADAR INDICATED

$$

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 7, 11:47 PM EDTFlash Flood WarningFFCCobb, Forsyth, Fulton, Gwinnett9 hr
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, 6:57 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.