Alert archive / Georgia / Flash Flood Warnings in 2013

Flash Flood Warning 101, NWS Atlanta, GA

October 6, 20134 counties in Georgia

NWS Atlanta, GA issued this flash flood warning at Oct 6, 2013, 9:19 PM EDT for 4 counties in Georgia. It was in force for 6 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
Oct 6, 2013, 9:19 PM EDT (01:19 UTC)
Expired
Oct 7, 2013, 3:15 AM EDT
In force
6 hr
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

Counties DeKalb County, GA, Forsyth County, GA, Fulton County, GA, Gwinnett County, GA

The radar

The Atlanta radar (KFFC), 85 km from the middle of the area, began a volume at 01:23 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
Oct 7, 2:05 AM EDTFLASH FLOOD6 Sw Cumming, GATHE STAGE HEIGHT AT A USGS STREAM GAGE ON THE BIG CREEK AT ATLANTA HIGHWAY 6 MILES SOUTHWEST OF CUMMING REACHED FLOOD STAGE. THE CREEK CREST AROUND 6 FEET. MINOR FLOODING OCCURRED ON LARGE PORTIONS OF THE SIDEWALKS AND BOARDWALKS OF THE BIG CREEK GREENWAY.

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, 1.3 hours before the alert went out and 82 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 2013-10-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 875 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 2013-10-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 146 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
875 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
549 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
146 m²/s²
0-3 km storm-relative helicity
148 m²/s²
Significant tornado parameter
0.9
Supercell composite
4.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

016 
WGUS52 KFFC 070119
FFWFFC
GAC089-117-121-135-070715-
/O.NEW.KFFC.FF.W.0101.131007T0119Z-131007T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
919 PM EDT SUN OCT 6 2013

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHERN DEKALB COUNTY IN NORTH CENTRAL GEORGIA
  SOUTHERN FORSYTH COUNTY IN NORTH CENTRAL GEORGIA
  NORTHEASTERN FULTON COUNTY IN NORTH CENTRAL GEORGIA
  GWINNETT COUNTY IN NORTH CENTRAL GEORGIA

* UNTIL 315 AM EDT

* AT 912 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN POTENTIALLY LEADING TO FLASH FLOODING FROM A    
  SERIES OF THUNDERSTORMS OVER THE WARNED AREA. UP TO 2 INCHES OF
  RAIN HAVE FALLEN ACROSS THE WARNED AREA WITH AN ADDITIONAL INCH
  POSSIBLE THROUGH 11 PM.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SANDY
  SPRINGS...MOUNTAIN PARK...SUWANEE...SUGAR HILL...REST HAVEN...
  NORCROSS...LAWRENCEVILLE...DULUTH...BUFORD...BERKELEY LAKE...
  DUNWOODY...JOHNS CREEK...MILTON...ROSWELL...ALPHARETTA AND CUMMING.
  FLASH FLOODING WILL BE POSSIBLE ON SEVERAL AREA CREEKS AND STREAMS
  SUCH AS CROOKED CREEK...BIG CREEK...NANCY CREEK...PEACHTREE 
  CREEK...SWEETWATER CREEK...AND SUWANEE CREEK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES
AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.

IF YOU SEE SIGNIFICANT FLOODING CALL THE NATIONAL WEATHER SERVICE
TOLL FREE AT 1 8 6 6 7 6 3 4 4 6 6. YOU CAN ALSO TWEET YOUR REPORT
USING HASHTAG GAWX.

&&

LAT...LON 3423 8397 3422 8396 3419 8399 3418 8406
      3416 8406 3412 8392 3380 8397 3374 8403
      3376 8456 3383 8445 3391 8445 3398 8437
      3406 8442 3410 8442 3413 8436 3417 8435
      3419 8426 3424 8425

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 6, 8:56 PM EDTSpecial Weather StatementFFCDeKalb, Fulton, Gwinnett49 min
Oct 7, 12:05 AM EDTRiver Flood WarningFFCForsyth, Fulton22 hr
Oct 7, 3:05 AM EDTRiver Flood WarningFFCForsyth24 hr
Oct 7, 9:27 AM EDTSpecial Weather StatementFFCSumter63 min

Nearby

Flash Flood Warnings in Georgia, 2013Every flash flood warning in 2013

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.