Alert archive / Georgia / Flash Flood Warnings in 2010

Flash Flood Warning 13, NWS Atlanta, GA

July 26, 2010Gwinnett County, Georgia

NWS Atlanta, GA issued this flash flood warning at Jul 26, 2010, 6:31 PM EDT for Gwinnett County, Georgia. It was in force for 4 hr. 1 report 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: Jul 26, 2010, 6:31 PM EDT (22:31 UTC)
Expired: Jul 26, 2010, 10:34 PM EDT
In force: 4 hr
Issued by: NWS Atlanta, GA
Area: Storm-based polygon
Flood severity: None

County Gwinnett County, GA

The radar

The Atlanta radar (KFFC), 75 km from the middle of the area, began a volume at 22:33 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

Time	Report	Where	Remark
Jul 26, 7:30 PM EDT	FLASH FLOOD	4 Ne Lilburn, GA	THE USGS GAGE ON THE SWEETWATER CREEK AT CLUB DRIVE REACHED FLOOD STAGE OF 11 FEET. MINOR FLOODING WAS OCCURRING.

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, 10.5 hours before the alert went out and 71 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: 1811 J/kg
Mixed-layer CIN: -94 J/kg
Mixed-layer LCL: 938 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: -32 m²/s²
0-3 km storm-relative helicity: -3 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.

983 
WGUS52 KFFC 262231
FFWFFC
GAC135-270430-
/O.NEW.KFFC.FF.W.0013.100726T2231Z-100727T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
631 PM EDT MON JUL 26 2010

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL GWINNETT COUNTY IN NORTH CENTRAL GEORGIA

* UNTIL 1230 AM EDT

* AT 615 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  POSSIBLE FLASH FLOODING ON SWEETWATER CREEK FROM THUNDERSTORMS     
  OVER THE WARNED AREA. RAINFALL AMOUNTS UP TO 4 INCHES HAS OCCURRED 
  AT THE GAGE ON CLUB DRIVE. THE STAGE HEIGHT WAS 9.2 FEET AND       
  RISING. FLOOD STAGE IS 11 FEET. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO BERKELEY
  LAKE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLOOD WATERS ARE MOVING DOWN THE SWEETWATER CREEK IN GWINNETT 
COUNTY. MINOR FLOODING IS EXPECTED OF THE GOLF COURSE AND THE 
NATURAL FLOOD PLAIN AT THIS TIME.

IF YOU SEE SIGNIFICANT FLOODING CALL THE NATIONAL WEATHER SERVICE
TOLL FREE AT 1 8 6 6 7 6 3 4 4 6 6.

&&

LAT...LON 3400 8419 3400 8403 3386 8405 3382 8410
      3387 8418

$$

16

2 follow-up statements

854 
WGUS72 KFFC 270013
FFSFFC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
813 PM EDT MON JUL 26 2010

GAC135-270430-
/O.CON.KFFC.FF.W.0013.000000T0000Z-100727T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GWINNETT GA-
813 PM EDT MON JUL 26 2010

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1230 AM EDT FOR
CENTRAL GWINNETT COUNTY...

AT 800 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
2 TO 4 INCHES OF RAIN HAD FALLEN OVER THE WARNED AREA SINCE 400 PM 
EDT. FLASH FLOODING WAS OCCURRING ON THE SWEETWATER CREEK NEAR 
LILBURN THIS EVENING. 

AT 800 PM EDT... THE STAGE WAS 11 FEET...AND RISING. FLOOD STAGE IS 
11 FEET. THE RAIN HAS DIMINISHED OVER THE WARNED AREA AND THE CREEK 
MAY RISE TO NEAR 12 FEET BEFORE CRESTING PRIOR TO MIDNIGHT. 

AT 11 FEET...MINOR FLOODING WILL OCCUR IN PORTIONS OF THE NORTHWOOD 
COUNTRY CLUB GOLF COURSE UPSTREAM FROM THE GAGE ON CLUB DRIVE...AND 
IN THE WOODLAND AREAS DOWNSTREAM FROM THE GAGE AND FOR THE NEXT FOUR 
MILES UNTIL THE CREEK MERGES WITH THE YELLOW RIVER. AN OLD CONCRETE 
GOLF CART BRIDGE AROUND 300 FEET DOWNSTREAM FROM THE GAGE WILL BEGIN 
TO FLOOD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU SEE SIGNIFICANT FLOODING CALL THE NATIONAL WEATHER SERVICE
TOLL FREE AT 1 8 6 6 7 6 3 4 4 6 6.

&&

LAT...LON 3400 8419 3400 8403 3386 8405 3382 8410
      3387 8418

$$

16

885 
WGUS72 KFFC 270234
FFSFFC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1034 PM EDT MON JUL 26 2010

GAC135-270255-
/O.CAN.KFFC.FF.W.0013.000000T0000Z-100727T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GWINNETT GA-
1034 PM EDT MON JUL 26 2010

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR CENTRAL GWINNETT
COUNTY...

THE RAIN HAS DIMINISHED OVER THE PREVIOUSLY WARNED AREA AND ALL 
STREAMS AND CREEKS ARE RECEDING. THE SWEETWATER CREEK AT CLUB DRIVE 
CRESTED AT 11.2 FEET AT 815 PM EDT...AND CAUSED MINOR FLOODING OF 
THE GOLF COURSE AND WOODED AREAS OF THE FLOOD PLAIN. FLOOD STAGE IS 
11 FEET. AT 1015 PM EDT...THE STAGE WAS 10.5 FEET AND FALLING. THE 
CREEK WILL CONTINUE TO FALL THROUGHOUT THE NIGHT.

LAT...LON 3400 8419 3400 8403 3386 8405 3382 8410
      3387 8418

$$

16

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 26, 2:07 AM EDT	Flash Flood Warning	FFC	Coweta	6 hr
Jul 26, 1:47 PM EDT	Severe Thunderstorm Warning	FFC	Dawson, Gilmer	43 min
Jul 26, 2:11 PM EDT	Flash Flood Warning	FFC	Dawson, Gilmer	3 hr
Jul 26, 3:12 PM EDT	Severe Thunderstorm Warning	FFC	Catoosa, Whitfield	48 min
Jul 26, 4:27 PM EDT	Severe Thunderstorm Warning	FFC	Clarke, Jackson, Madison	48 min
Jul 26, 4:35 PM EDT	Severe Thunderstorm Warning	FFC	Gwinnett	40 min
Jul 26, 4:56 PM EDT	Severe Thunderstorm Warning	FFC	Forsyth, Fulton, Gwinnett	49 min
Jul 26, 5:14 PM EDT	Severe Thunderstorm Warning	FFC	Floyd	46 min
Jul 26, 5:41 PM EDT	Severe Thunderstorm Warning	FFC	Floyd, Polk	49 min
Jul 26, 6:02 PM EDT	Severe Thunderstorm Warning	FFC	Cobb, Fulton	43 min
Jul 26, 6:43 PM EDT	Severe Thunderstorm Warning	FFC	Glascock, Hancock, Jefferson, Warren, Washington	47 min

Nearby

Flash Flood Warnings in Georgia, 2010 Every flash flood warning in 2010

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.