Alert archive / Georgia / Flash Flood Warnings in 2015

Flash Flood Warning 50, NWS Atlanta, GA

December 28, 2015DeKalb County, Georgia

NWS Atlanta, GA issued this flash flood warning at Dec 28, 2015, 9:45 PM EST for DeKalb 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: Dec 28, 2015, 9:45 PM EST (02:45 UTC)
Expired: Dec 29, 2015, 3:45 AM EST
In force: 6 hr
Issued by: NWS Atlanta, GA
Area: Storm-based polygon
Flood severity: None

County DeKalb County, GA

The radar

The Atlanta radar (KFFC), 44 km from the middle of the area, began a volume at 02:49 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, 2.8 hours before the alert went out and 40 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: 9 J/kg
Mixed-layer CIN: -89 J/kg
Mixed-layer LCL: 520 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 560 m²/s²
0-3 km storm-relative helicity: 604 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

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

199 
WGUS52 KFFC 290245
FFWFFC
GAC089-290845-
/O.NEW.KFFC.FF.W.0050.151229T0245Z-151229T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
945 PM EST MON DEC 28 2015

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

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

* UNTIL 345 AM EST TUESDAY

* AT 940 PM EST...GAUGE REPORTS INDICATED HEAVY RAIN FALLING ACROSS
  THE WARNED AREA. FLASH FLOODING IS ALREADY OCCURING.

THIS INCLUDES THE FOLLOWING STREAMS AND DRAINAGES...COBBS CREEK...
INTRENCHMENT CREEK...SUGAR CREEK AND SOUTH RIVER.

FLOOD WATERS ARE MOVING DOWN INTRENCHMENT CREEK FROM NEAR THE I-285 
AND I675 MERGE SOUTHWEST OF GRESHAM PARK. FLOODING MAY EXPAND INTO THE
WOODLANDS UPSTREAM AND DOWNSTREAM FROM THE GAGE AT CONSTITUTION
ROAD. THE WATER LEVEL WILL BE CLOSE TO THE BOTTOM OF THE BRIDGE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF 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 OR TWEET US YOUR WARNING AT
NWSATLANTA.

&&

LAT...LON 3368 8434 3370 8434 3370 8425 3368 8425

$$

1 follow-up statement

547 
WGUS72 KFFC 290354
FFSFFC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1054 PM EST MON DEC 28 2015

GAC089-290404-
/O.CAN.KFFC.FF.W.0050.000000T0000Z-151229T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DEKALB GA-
1054 PM EST MON DEC 28 2015

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN DEKALB COUNTY IS
CANCELLED...

FLOOD WATERS HAVE RECEDED...AND ARE NO LONGER EXPECTED TO POSE A
THREAT TO LIFE OR PROPERTY. 

LAT...LON 3368 8434 3370 8434 3370 8425 3368 8425

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Dec 28, 7:45 PM EST	Special Weather Statement	FFC	Talbot	30 min
Dec 28, 8:48 PM EST	Special Weather Statement	FFC	Talbot, Upson	27 min
Dec 28, 9:19 PM EST	Special Weather Statement	FFC	Upson	26 min
Dec 28, 9:20 PM EST	Special Weather Statement	FFC	Schley	25 min
Dec 28, 9:26 PM EST	River Flood Warning	FFC	DeKalb	24 hr
Dec 28, 9:32 PM EST	River Flood Warning	FFC	Towns	11 hr
Dec 28, 10:01 PM EST	Areal Flood Warning	FFC	Lamar, Pike, Talbot, Upson	6 hr
Dec 28, 11:45 PM EST	River Flood Warning	FFC	Towns	24 hr
Dec 29, 1:06 AM EST	River Flood Warning	FFC	Forsyth	24 hr
Dec 29, 1:06 AM EST	River Flood Warning	FFC	Gwinnett, Walton	24 hr
Dec 29, 12:29 PM EST	River Flood Warning	FFC	Chattooga	11 hr
Dec 29, 12:29 PM EST	River Flood Warning	FFC	Gwinnett	11 hr
Dec 29, 4:23 PM EST	River Flood Warning	FFC	Gordon, Murray	5 days
Dec 29, 5:06 PM EST	River Flood Warning	FFC	Gordon	4 days
Dec 29, 5:06 PM EST	River Flood Warning	FFC	Gordon	4 days

Nearby

Flash Flood Warnings in Georgia, 2015 Every flash flood warning in 2015

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.