Alert archive / Georgia / Flash Flood Warnings in 2012

Flash Flood Warning 21, NWS Atlanta, GA

October 1, 20124 counties in Georgia

NWS Atlanta, GA issued this flash flood warning at Oct 1, 2012, 10:17 PM EDT for 4 counties in Georgia. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Oct 1, 2012, 10:17 PM EDT (02:17 UTC)
Expired
Oct 2, 2012, 1:14 AM EDT
In force
3 hr
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

Counties Meriwether County, GA, Pike County, GA, Spalding County, GA, Upson County, GA

The radar

The Atlanta radar (KFFC), 44 km from the middle of the area, began a volume at 02:19 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

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 2.3 hours before the alert went out and 43 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 2012-10-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 988 joules per kilogram.LCLEL10008507005003002001001 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 2012-10-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 263 square meters per square second.19395878Sfc1 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
988 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
481 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
263 m²/s²
0-3 km storm-relative helicity
292 m²/s²
Significant tornado parameter
1.8
Supercell composite
6.7

Open this sounding in Storm Lab

The text

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

712 
WGUS52 KFFC 020217
FFWFFC
GAC199-231-255-293-020815-
/O.NEW.KFFC.FF.W.0021.121002T0217Z-121002T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1017 PM EDT MON OCT 1 2012

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN MERIWETHER COUNTY IN WEST CENTRAL GEORGIA
  PIKE COUNTY IN WEST CENTRAL GEORGIA
  CENTRAL SPALDING COUNTY IN WEST CENTRAL GEORGIA
  NORTHWESTERN UPSON COUNTY IN WEST CENTRAL GEORGIA

* UNTIL 415 AM EDT TUESDAY

* AT 1009 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED 
FLASH FLOODING FROM HEAVY RAINFALL OVER THE WARNED AREA. DOPPLER 
RADAR HAS INDICATED THAT 1 TO 2 INCHES HAVE FALLEN IN THE LAST THREE 
HOURS...IN ADDITION TO 1 TO 2 INCHES THAT HAD ALREADY FALLEN EARLIER 
TODAY.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO WILLIAMSON
  AND GRIFFIN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE POSSIBLE IN THE
WARNED AREA.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

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 3307 8450 3333 8436 3333 8420 3283 8445
      3285 8447 3286 8449 3287 8447 3288 8449
      3285 8456 3285 8459

$$
1 follow-up statement
245 
WGUS72 KFFC 020514
FFSFFC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
114 AM EDT TUE OCT 2 2012

GAC199-231-255-293-020523-
/O.CAN.KFFC.FF.W.0021.000000T0000Z-121002T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SPALDING GA-PIKE GA-MERIWETHER GA-UPSON GA-
114 AM EDT TUE OCT 2 2012

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR NORTHWESTERN
UPSON...SOUTHEASTERN MERIWETHER...PIKE AND CENTRAL SPALDING
COUNTIES...

RUNOFF FROM THE HEAVY RAIN THAT FELL MONDAY EVENING HAS SUBSIDED AND 
NO LONGER POSES A THREAT OF PRODUCING FLASH FLOODING.

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 3307 8450 3333 8436 3333 8420 3283 8445
      3285 8447 3286 8449 3287 8447 3288 8449
      3285 8456 3285 8459

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 1, 9:23 PM EDTFlash Flood WarningFFCHall6 hr
Oct 1, 10:45 PM EDTSpecial Weather StatementFFCDeKalb, Gwinnett60 min
Oct 1, 10:54 PM EDTSpecial Weather StatementFFCDade36 min
Oct 1, 10:56 PM EDTFlash Flood WarningFFCDeKalb, Gwinnett6 hr
Oct 2, 1:18 AM EDTRiver Flood WarningFFCGwinnett3 hr
Oct 2, 1:18 AM EDTRiver Flood WarningFFCGwinnett6 hr
Oct 2, 2:49 AM EDTFlash Flood WarningFFCWhite5 hr
Oct 2, 4:10 AM EDTRiver Flood WarningFFCGwinnett, Walton6 hr
Oct 2, 6:41 AM EDTRiver Flood WarningFFCGwinnett18 hr
Oct 2, 11:26 AM EDTRiver Flood WarningFFCDeKalb, Rockdale8 hr

Nearby

Flash Flood Warnings in Georgia, 2012Every flash flood warning in 2012

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.