Alert archive / Georgia / Flash Flood Warnings in 2017

Flash Flood Warning 48, NWS Atlanta, GA

September 11, 20175 counties in Georgia

NWS Atlanta, GA issued this flash flood warning at Sep 11, 2017, 9:05 PM EDT for 5 counties in 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 11, 2017, 9:05 PM EDT (01:05 UTC)
Expired
Sep 12, 2017, 3:00 AM EDT
In force
6 hr
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

Counties Catoosa County, GA, Fannin County, GA, Gilmer County, GA, Murray County, GA, Whitfield County, GA

The radar

The Northeast Alabama radar (KHTX), 122 km from the middle of the area, began a volume at 01:08 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

Nashville Metro, TN (KBNA), launched 00:00Z, 1.1 hours before the alert went out and 229 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, Nashville Metro, TN at 00:00Z on 2017-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Nashville Metro, TN at 00:00Z on 2017-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 179 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1058 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
179 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.

932 
WGUS52 KFFC 120105
FFWFFC
GAC047-111-123-213-313-120700-
/O.NEW.KFFC.FF.W.0048.170912T0105Z-170912T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Peachtree City GA
905 PM EDT MON SEP 11 2017

The National Weather Service in Peachtree City has issued a

* Flash Flood Warning for...
  Catoosa County in northwestern Georgia...
  Murray County in northwestern Georgia...
  Gilmer County in north central Georgia...
  Whitfield County in northwestern Georgia...
  Northwestern Fannin County in north central Georgia...

* Until 300 AM EDT

* At 904 PM EDT, Doppler radar indicated heavy rain across the 
  warned area. Rainfall amounts of 2 to 3 inches have occurred over 
  the last several hours. Isolated flash flooding is expected to 
  begin shortly.

* Some locations that will experience flooding include...
  Dalton, Chatsworth, Ringgold, Ellijay, Blue Ridge, Fort Oglethorpe,
  Varnell, Eton, Tunnel Hill, Cohutta, East Ellijay, Crandall, Sumac,
  Jones Mill, Higdon, Gregory, Blue Spring, Cohutta Wilderness,
  Epworth and Conasauga Lake.

Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.

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 report at
NWSATLANTA.

&&

LAT...LON 3499 8431 3484 8427 3455 8446 3456 8447
      3455 8449 3457 8450 3455 8452 3455 8464
      3458 8465 3460 8473 3462 8472 3461 8480
      3470 8505 3472 8505 3474 8516 3477 8515
      3478 8520 3485 8520 3486 8525 3499 8526

$$
1 follow-up statement
790 
WGUS72 KFFC 120236
FFSFFC

Flash Flood Statement
National Weather Service Peachtree City GA
1036 PM EDT MON SEP 11 2017

GAC047-111-123-213-313-120245-
/O.CAN.KFFC.FF.W.0048.000000T0000Z-170912T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Catoosa GA-Murray GA-Gilmer GA-Whitfield GA-Fannin GA-
1036 PM EDT MON SEP 11 2017

...THE FLASH FLOOD WARNING FOR CATOOSA...MURRAY...GILMER...WHITFIELD
AND NORTHWESTERN FANNIN COUNTIES IS CANCELLED...

The heavy rain has ended. Light rain continues over the area, and 
additional rainfall amounts of up to 0.5 inches are still possible. 
Flash flooding is no longer expected to pose a threat. Please 
continue to heed any remaining road closures.

LAT...LON 3499 8431 3484 8427 3455 8446 3456 8447
      3455 8449 3457 8450 3455 8452 3455 8464
      3458 8465 3460 8473 3462 8472 3461 8480
      3470 8505 3472 8505 3474 8516 3477 8515
      3478 8520 3485 8520 3486 8525 3499 8526

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 11, 8:06 PM EDTSpecial Weather StatementFFCLamar, Monroe24 min
Sep 11, 8:15 PM EDTSpecial Weather StatementFFCJones, Monroe30 min
Sep 11, 8:21 PM EDTSpecial Weather StatementFFCPutnam24 min
Sep 11, 8:41 PM EDTSpecial Weather StatementFFCButts34 min
Sep 11, 9:04 PM EDTSpecial Weather StatementFFCHancock26 min
Sep 11, 9:08 PM EDTSpecial Weather StatementFFCWilkes37 min
Sep 11, 9:38 PM EDTSpecial Weather StatementFFCJasper37 min
Sep 11, 10:56 PM EDTWind AdvisoryFFCBaldwin, Banks, Barrow, Bartow, Butts, Carroll and 59 more4 hr
Sep 12, 4:02 AM EDTRiver Flood WarningFFCCarroll, Coweta, Heard34 hr
Sep 12, 4:18 AM EDTRiver Flood WarningFFCCobb, Douglas44 hr
Sep 12, 4:23 AM EDTRiver Flood WarningFFCBibb, Houston, Jones, Monroe, Twiggs3 days
Sep 12, 4:23 AM EDTRiver Flood WarningFFCJohnson, Washington, Wilkinson24 hr
Sep 12, 8:41 AM EDTRiver Flood WarningFFCGwinnett12 hr

Nearby

Flash Flood Warnings in Georgia, 2017Every flash flood warning in 2017

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.