Alert archive / Georgia / Flash Flood Warnings in 2009

Flash Flood Warning 29, NWS Atlanta, GA

September 20, 2009White County, Georgia

NWS Atlanta, GA issued this flash flood warning at Sep 20, 2009, 6:43 AM EDT for White 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, 6:43 AM EDT (10:43 UTC)
Expired
Sep 20, 2009, 12:45 PM EDT
In force
6 hr
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

County White County, GA

The radar

The Greer radar (KGSP), 142 km from the middle of the area, began a volume at 10:46 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, 10.7 hours before the alert went out and 159 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 2009-09-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1577 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 2009-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 70 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
1577 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
548 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
177 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 201043
FFWFFC
GAC311-201645-
/O.NEW.KFFC.FF.W.0029.090920T1043Z-090920T1645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WHITE COUNTY IN NORTHEAST GEORGIA

* UNTIL 1245 PM EDT

* AT 642 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN FROM HEAVY SHOWERS AND THUNDERSTORMS...NORTHEAST 
  AT 10 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  UNICOI STATE PARK.

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 3476 8362 3471 8362 3464 8366 3454 8362
      3451 8367 3450 8384 3453 8383 3455 8386
      3462 8388 3471 8385 3474 8382 3476 8383
      3479 8379 3479 8367

$$
1 follow-up statement
000 
WGUS72 KFFC 201301
FFSFFC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
901 AM EDT SUN SEP 20 2009

GAC311-201645-
/O.CON.KFFC.FF.W.0029.000000T0000Z-090920T1645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WHITE GA-
901 AM EDT SUN SEP 20 2009

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1245 PM EDT FOR
WHITE COUNTY...

AT 857 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE SHOWERS PRODUCING HEAVY RAIN OVER THE WARNED AREA. FLOODING 
IS OCCURRING OR IS IMMINENT. WHILE MOST OF THE HEAVIEST RAIN HAS 
MOVED OUT OF THE AREA...RUNOFF WILL CONTINUE...AND ADDITIONAL STORMS 
ARE EXPECTED THROUGH THE DAY.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO UNICOI STATE
PARK AND HELEN

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLOODING IS OCCURRING OR IS IMMINENT. IT IS IMPORTANT TO KNOW WHERE
YOU ARE RELATIVE TO STREAMS...RIVERS...OR CREEKS WHICH CAN BECOME
KILLERS IN HEAVY RAINS. CAMPERS AND HIKERS SHOULD AVOID STREAMS OR
CREEKS.

IN HILLY TERRAIN THERE ARE LOW WATER CROSSINGS WHICH ARE POTENTIALLY
DANGEROUS IN HEAVY RAIN. DO NOT ATTEMPT TO TRAVEL ACROSS FLOODED
ROADS...FIND ALTERNATE ROUTES. IT ONLY TAKES A FEW INCHES OF SWIFTLY
FLOWING WATER TO CARRY VEHICLES AWAY.

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 3476 8362 3471 8362 3464 8366 3454 8362
      3451 8367 3450 8384 3453 8383 3455 8386
      3462 8388 3471 8385 3474 8382 3476 8383
      3479 8379 3479 8367

$$

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, 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, 6:32 PM EDTFlash Flood WarningFFCCatoosa, Walker6 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.