Alert archive / Georgia / Flash Flood Warnings in 2011

Flash Flood Warning 14, NWS Atlanta, GA

December 23, 2011DeKalb County, Georgia

NWS Atlanta, GA issued this flash flood warning at Dec 23, 2011, 12:18 AM EST for DeKalb County, Georgia. It was in force for 10 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Dec 23, 2011, 12:18 AM EST (05:18 UTC)
Expired
Dec 23, 2011, 12:28 AM EST
In force
10 min
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

County DeKalb County, GA

The radar

The Atlanta radar (KFFC), 43 km from the middle of the area, began a volume at 05:18 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

Birmingham, AL (KBMX), launched 00:00Z, 5.3 hours before the alert went out and 237 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, Birmingham, AL at 00:00Z on 2011-12-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Birmingham, AL at 00:00Z on 2011-12-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -188 square meters per square second.1939587897117Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1047 m above ground
0-6 km bulk shear
75 kt
0-1 km storm-relative helicity
-188 m²/s²
0-3 km storm-relative helicity
-284 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.

210 
WGUS52 KFFC 230518
FFWFFC
GAC089-231115-
/O.NEW.KFFC.FF.W.0014.111223T0518Z-111223T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1218 AM EST FRI DEC 23 2011

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHWESTERN DEKALB COUNTY IN NORTH CENTRAL GEORGIA

* UNTIL 615 AM EST

* AT 1211 AM EST...THE RIVER STAGE ON BIG CREEK AT CUMMING HAD
  REACHED 5.96 FEET. FLOOD STAGE IS 6.0 FEET. THE RIVER IS EXPECTED
  TO CREST JUST ABOVE 6.0 FEET WITHIN THE NEXT HOUR...THEN FALL BELOW
  FLOOD STAGE LATER TONIGHT.

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

HEAVY RAIN FELL ACROSS THIS AREA DURING THE PAST TWO DAYS...WITH 
RAINFALL AMOUNTS NEAR 2.0 INCHES SINCE WEDNESDAY. THIS HAS CAUSED 
BIG CREEK TO SWELL TO FLOOD STAGE...IN LESS THAN SIX HOURS. THUS...A 
FLASH FLOOD WARNING IS BEING ISSUED.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING. 
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY. 
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE 
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS 
SWIFTLY FLOWING WATERS...OR WATERS OF UNKNOWN DEPTH...ON FOOT OR IN 
AN AUTOMOBILE.

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 3372 8432 3372 8424 3365 8427 3365 8432
      3365 8433

$$
1 follow-up statement
902 
WGUS72 KFFC 230528
FFSFFC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1228 AM EST FRI DEC 23 2011

GAC089-230536-
/O.CAN.KFFC.FF.W.0014.000000T0000Z-111223T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DEKALB GA-
1228 AM EST FRI DEC 23 2011

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR SOUTHWESTERN DEKALB
COUNTY...

THE FLASH FLOOD WARNING ISSUED FOR SOUTHWEST DEKALB COUNTY WAS 
INTENDED FOR BIG CREEK IN SOUTHWEST FORSYTH COUNTY. THERE IS NO 
FLASH FLOODING OBSERVED ALONG CREEKS OR STREAMS IN DEKALB COUNTY AT 
THIS TIME.

LAT...LON 3372 8432 3372 8424 3365 8427 3365 8432
      3365 8433

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 22, 7:02 PM ESTSpecial Weather StatementFFCDooly, Houston, Macon, Peach, Schley, Taylor58 min
Dec 22, 7:43 PM ESTRiver Flood WarningFFCDade8 hr
Dec 22, 7:54 PM ESTSpecial Weather StatementFFCBleckley, Houston51 min
Dec 22, 8:57 PM ESTRiver Flood WarningFFCMurray, Whitfield26 hr
Dec 22, 9:06 PM ESTRiver Flood WarningFFCForsyth, Fulton10 hr
Dec 23, 12:25 AM ESTFlash Flood WarningFFCForsyth76 min
Dec 23, 2:57 AM ESTRiver Flood WarningFFCWhitfield37 hr

Nearby

Flash Flood Warnings in Georgia, 2011Every flash flood warning in 2011

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.