Alert archive / Georgia / Flash Flood Warnings in 2018

Flash Flood Warning 24, NWS Atlanta, GA

July 13, 2018Cobb County, DeKalb County, Fulton County, Georgia

NWS Atlanta, GA issued this flash flood warning at Jul 13, 2018, 9:30 PM EDT for Cobb County, DeKalb County, Fulton County, Georgia. It was in force for 4 hr. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 13, 2018, 9:30 PM EDT (01:30 UTC)
Expired
Jul 14, 2018, 1:28 AM EDT
In force
4 hr
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

Counties Cobb County, GA, DeKalb County, GA, Fulton County, GA

The radar

The Atlanta radar (KFFC), 75 km from the middle of the area, began a volume at 01:31 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.

What was reported inside it

TimeReportWhereRemark
Jul 13, 9:30 PM EDTFLASH FLOOD1 N Roswell, GAMINOR STREET FLOODING WAS REPORTED ALONG CRABAPPLE ROAD IN ROSWELL.
Jul 13, 9:45 PM EDTFLASH FLOOD2 Ne Roswell, GAROAD FLOODED ON HOUZE RD BETWEEN HWY 9 AND MANSELL RD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 1.5 hours before the alert went out and 72 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 2018-07-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1421 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 2018-07-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -8 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
1421 J/kg
Mixed-layer CIN
-42 J/kg
Mixed-layer LCL
977 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
-8 m²/s²
0-3 km storm-relative helicity
-15 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

556 
WGUS52 KFFC 140130
FFWFFC
GAC067-089-121-140730-
/O.NEW.KFFC.FF.W.0024.180714T0130Z-180714T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Peachtree City GA
930 PM EDT FRI JUL 13 2018

The National Weather Service in Peachtree City has issued a

* Flash Flood Warning for...
  Northwestern DeKalb County in north central Georgia...
  East central Cobb County in north central Georgia...
  Northeastern Fulton County in north central Georgia...

* Until 330 AM EDT.

* At 930 PM EDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Flash flooding is expected to
  begin shortly.

* Some locations that will experience flooding include...
  Sandy Springs, Roswell, Alpharetta, Dunwoody, Chamblee and Mount
  Bethel.

LAT...LON 3404 8423 3389 8431 3395 8448 3410 8438

$$
1 follow-up statement
588 
WGUS72 KFFC 140528
FFSFFC

Flash Flood Statement
National Weather Service Peachtree City GA
128 AM EDT SAT JUL 14 2018

GAC067-089-121-140536-
/O.CAN.KFFC.FF.W.0024.000000T0000Z-180714T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DeKalb GA-Cobb GA-Fulton GA-
128 AM EDT SAT JUL 14 2018

...THE FLASH FLOOD WARNING FOR NORTHWESTERN DEKALB...EAST CENTRAL
COBB AND NORTHEASTERN FULTON COUNTIES IS CANCELLED...

The heavy rain across this area has ended and gauges on small 
streams indicate that water levels on creeks and streams in the area 
are receding. Flooding is no longer expected to pose a threat. 
Please continue to heed any remaining road closures.

LAT...LON 3404 8423 3389 8431 3395 8448 3410 8438

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 13, 8:13 PM EDTSpecial Weather StatementFFCGwinnett32 min
Jul 13, 8:40 PM EDTFlash Flood WarningFFCGwinnett5 hr
Jul 13, 8:43 PM EDTSpecial Weather StatementFFCGwinnett32 min
Jul 13, 9:13 PM EDTSpecial Weather StatementFFCCobb32 min
Jul 13, 9:59 PM EDTSpecial Weather StatementFFCSumter46 min
Jul 14, 2:26 AM EDTSpecial Weather StatementFFCDawson64 min
Jul 14, 6:36 AM EDTSpecial Weather StatementFFCForsyth54 min
Jul 14, 7:30 AM EDTSpecial Weather StatementFFCForsyth30 min
Jul 14, 12:45 PM EDTSpecial Weather StatementFFCWebster30 min
Jul 14, 1:11 PM EDTSpecial Weather StatementFFCWebster34 min
Jul 14, 2:05 PM EDTSpecial Weather StatementFFCMarion25 min
Jul 14, 3:06 PM EDTSpecial Weather StatementFFCSchley24 min
Jul 14, 3:07 PM EDTSpecial Weather StatementFFCTaylor38 min
Jul 14, 3:28 PM EDTSpecial Weather StatementFFCSchley32 min
Jul 14, 3:43 PM EDTSpecial Weather StatementFFCTaylor32 min
Jul 14, 4:16 PM EDTSpecial Weather StatementFFCOglethorpe29 min
Jul 14, 4:18 PM EDTSpecial Weather StatementFFCTalbot27 min
Jul 14, 4:34 PM EDTSpecial Weather StatementFFCJasper26 min
Jul 14, 4:57 PM EDTSpecial Weather StatementFFCJasper33 min
Jul 14, 5:19 PM EDTSpecial Weather StatementFFCBaldwin26 min
Jul 14, 5:26 PM EDTSpecial Weather StatementFFCClayton, Fulton34 min
Jul 14, 5:29 PM EDTSpecial Weather StatementFFCJasper31 min
Jul 14, 5:33 PM EDTSpecial Weather StatementFFCWilcox42 min
Jul 14, 5:57 PM EDTSpecial Weather StatementFFCClayton, Cobb, Fulton33 min
Jul 14, 6:13 PM EDTSpecial Weather StatementFFCTelfair, Wilcox47 min
Jul 14, 6:28 PM EDTSpecial Weather StatementFFCClayton, Coweta, Fayette32 min
Jul 14, 6:29 PM EDTSpecial Weather StatementFFCCobb31 min
Jul 14, 6:55 PM EDTSpecial Weather StatementFFCCoweta35 min
Jul 14, 6:56 PM EDTSpecial Weather StatementFFCDodge, Telfair, Wilcox34 min
Jul 14, 6:59 PM EDTSpecial Weather StatementFFCBibb31 min
Jul 14, 7:06 PM EDTSpecial Weather StatementFFCCatoosa24 min
Jul 14, 7:27 PM EDTSpecial Weather StatementFFCCoweta33 min
Jul 14, 7:28 PM EDTSpecial Weather StatementFFCCatoosa, Walker32 min
Jul 14, 7:30 PM EDTSpecial Weather StatementFFCBibb, Bleckley, Dodge30 min
Jul 14, 7:32 PM EDTSpecial Weather StatementFFCTelfair28 min
Jul 14, 7:34 PM EDTSpecial Weather StatementFFCDooly26 min
Jul 14, 7:57 PM EDTSpecial Weather StatementFFCMeriwether33 min

Nearby

Flash Flood Warnings in Georgia, 2018Every flash flood warning in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.