Alert archive / Georgia / Flash Flood Warnings in 2008

Flash Flood Warning 6, NWS Atlanta, GA

July 8, 2008Forsyth County, Georgia

NWS Atlanta, GA issued this flash flood warning at Jul 8, 2008, 11:56 PM EDT for Forsyth 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: Jul 8, 2008, 11:56 PM EDT (03:56 UTC)
Expired: Jul 9, 2008, 6:00 AM EDT
In force: 6 hr
Issued by: NWS Atlanta, GA
Area: Storm-based polygon
Flood severity: None

County Forsyth County, GA

The radar

The Atlanta radar (KFFC), 110 km from the middle of the area, began a volume at 03:58 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, 3.9 hours before the alert went out and 108 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1306 J/kg
Mixed-layer CIN: -15 J/kg
Mixed-layer LCL: 1363 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 34 m²/s²
0-3 km storm-relative helicity: 74 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 090357
FFWFFC
GAC117-091000-
/O.NEW.KFFC.FF.W.0006.080709T0356Z-080709T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1156 PM EDT TUE JUL 8 2008

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  FORSYTH COUNTY IN NORTH CENTRAL GEORGIA

* UNTIL 600 AM EDT WEDNESDAY

* AT 1154 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR
  INDICATED VERY HEAVY RAIN FROM A THUNDERSTORM OVER CENTRAL FORSYTH
  COUNTY...IN THE THALLEY CREEK BASIN.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO COAL
  MOUNTAIN AND ALONG THALLEY CREEK.

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 3432 8415 3432 8404 3423 8406 3422 8416

$$

1 follow-up statement

000 
WGUS72 KFFC 090658
FFSFFC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
255 AM EDT WED JUL 9 2008

GAC117-091000-
/O.CON.KFFC.FF.W.0006.000000T0000Z-080709T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FORSYTH GA-
255 AM EDT WED JUL 9 2008

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 600 AM EDT FOR
FORSYTH COUNTY...

AT 255 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS PRODUCING VERY HEAVY RAIN HAD MOVED OUT OF THE WARNED 
AREA.  PORTIONS OF THE WARNED AREA HAS RECEIVED 3 TO 4 INCHES OF 
RAINFALL BETWEEN TUESDAY EVENING AND EARLY WEDNESDAY MORNING.  

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO COAL MOUNTAIN

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.

LAT...LON 3432 8415 3432 8404 3423 8406 3422 8416

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 8, 8:00 PM EDT	Severe Thunderstorm Warning	FFC	Barrow, Gwinnett	29 min
Jul 8, 9:30 PM EDT	Severe Thunderstorm Warning	FFC	Banks, Hall, Jackson	49 min
Jul 9, 1:54 AM EDT	Flash Flood Warning	FFC	Dawson, Lumpkin	4 hr
Jul 9, 5:29 PM EDT	Severe Thunderstorm Warning	FFC	Bartow, Cherokee, Cobb	34 min

Nearby

Flash Flood Warnings in Georgia, 2008 Every flash flood warning in 2008

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.