Alert archive / Georgia / Flash Flood Warnings in 2009

Flash Flood Warning 32, NWS Atlanta, GA

September 20, 2009Catoosa County, Walker County, Georgia

NWS Atlanta, GA issued this flash flood warning at Sep 20, 2009, 6:32 PM EDT for Catoosa County, Walker County, Georgia. It was in force for 6 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
Sep 20, 2009, 6:32 PM EDT (22:32 UTC)
Expired
Sep 21, 2009, 12:30 AM EDT
In force
6 hr
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

Counties Catoosa County, GA, Walker County, GA

The radar

The Northeast Alabama radar (KHTX), 74 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.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 10.5 hours before the alert went out and 178 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 2009-09-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 977 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 2009-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 52 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
977 J/kg
Mixed-layer CIN
-26 J/kg
Mixed-layer LCL
520 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
52 m²/s²
0-3 km storm-relative helicity
132 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.

000 
WGUS52 KFFC 202232
FFWFFC
GAC047-295-210430-
/O.NEW.KFFC.FF.W.0032.090920T2232Z-090921T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
632 PM EDT SUN SEP 20 2009

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WESTERN CATOOSA COUNTY IN NORTHWEST GEORGIA
  WALKER COUNTY IN NORTHWEST GEORGIA

* UNTIL 1230 AM EDT

* AT 626 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
  VERY HEAVY RAIN FROM THUNDERSTORMS ALONG A LINE FROM CHICKAMAUGA
  TO NEAR CENTER POST..MOVING NORTH AT 10 MPH. RAINFALL AMOUNTS OF 
  TWO  TO THREE INCHES IN THE PAST THREE HOURS...HAVE OCCURRED IN 
  THE ACROSS PORTIONS OF WALKER AND WESTERN CATOOSA COUNTIES.
  ADDITIONAL SHOWERS WILL BE MOVING OVER THE SAME AREAS WITHIN THE 
  NEXT FEW HOURS...AND AN ADDITIONAL TWO TO THREE INCHES OF RAIN CAN 
  BE EXPECTED.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO FORT
  OGLETHORPE...CHICKAMAUGA...ROSSVILLE AND LOOKOUT MOUNTAIN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...AS WELL AS HIGHWAYS AND UNDERPASSES.
ADDITIONALLY...COUNTRY ROADS AND FARMLANDS ALONG THE BANKS OF
CREEKS...STREAMS AND OTHER LOW LYING AREAS ARE SUBJECT TO 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.

&&

LAT...LON 3500 8516 3459 8523 3459 8549 3500 8535

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 20, 5:37 AM EDTFlash Flood WarningFFCLumpkin6 hr
Sep 20, 6:34 AM EDTFlash Flood WarningFFCUnion6 hr
Sep 20, 6:43 AM EDTFlash Flood WarningFFCWhite6 hr
Sep 20, 7:40 AM EDTFlash Flood WarningFFCTowns6 hr
Sep 20, 11:23 AM EDTAreal Flood WarningFFCLumpkin112 min
Sep 20, 11:59 AM EDTRiver Flood WarningFFCClarke, Greene, Oconee5 days
Sep 20, 12:23 PM EDTAreal Flood WarningFFCUnion, White52 min
Sep 20, 1:17 PM EDTAreal Flood WarningFFCLumpkin, Towns, Union, White6 hr
Sep 20, 1:51 PM EDTAreal Flood WarningFFCCobb6 hr
Sep 20, 2:45 PM EDTFlash Flood WarningFFCCherokee6 hr
Sep 20, 5:35 PM EDTRiver Flood WarningFFCDawson, Forsyth38 hr
Sep 20, 6:56 PM EDTFlash Flood WarningFFCPaulding4 hr
Sep 20, 7:14 PM EDTFlash Flood WarningFFCCobb4 hr

Nearby

Flash Flood Warnings in Georgia, 2009Every flash flood warning in 2009

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.