Alert archive / Georgia / Flash Flood Warnings in 2020

Flash Flood Warning 70, NWS Atlanta, GA

November 12, 2020Towns County, White County, Georgia

NWS Atlanta, GA issued this flash flood warning at Nov 12, 2020, 1:37 AM EST for Towns County, White County, Georgia. It was in force for 5 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
Nov 12, 2020, 1:37 AM EST (06:37 UTC)
Expired
Nov 12, 2020, 6:24 AM EST
In force
5 hr
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

Counties Towns County, GA, White County, GA

The radar

The Greer radar (KGSP), 133 km from the middle of the area, began a volume at 06:38 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, 6.6 hours before the alert went out and 181 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 2020-11-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 410 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 2020-11-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 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
410 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
759 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
127 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

318 
WGUS52 KFFC 120637
FFWFFC
GAC281-311-121245-
/O.NEW.KFFC.FF.W.0070.201112T0637Z-201112T1245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Peachtree City GA
137 AM EST Thu Nov 12 2020

The National Weather Service in Peachtree City has issued a

* Flash Flood Warning for...
  Southeastern Towns County in northeastern Georgia...
  North Central White County in northeastern Georgia...

* Until 745 AM EST Thursday.

* At 137 AM EST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Mountain Scene and Blue Mountain Shelter.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

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

&&

LAT...LON 3479 8378 3482 8378 3482 8379 3494 8367
      3495 8359 3494 8359 3493 8360 3492 8359
      3490 8363 3489 8363 3489 8364 3488 8366
      3485 8366 3482 8365 3479 8368 3479 8367
      3478 8365 3477 8375 3479 8379

FLASH FLOOD...RADAR INDICATED

$$
1 follow-up statement
960 
WGUS72 KFFC 121124
FFSFFC

Flash Flood Statement
National Weather Service Peachtree City GA
624 AM EST Thu Nov 12 2020

GAC281-311-121134-
/O.CAN.KFFC.FF.W.0070.000000T0000Z-201112T1245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Towns GA-White GA-
624 AM EST Thu Nov 12 2020

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN TOWNS AND NORTH 
CENTRAL WHITE COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3479 8378 3482 8378 3482 8379 3494 8367
      3495 8359 3494 8359 3493 8360 3492 8359
      3490 8363 3489 8363 3489 8364 3488 8366
      3485 8366 3482 8365 3479 8368 3479 8367
      3478 8365 3477 8375 3479 8379

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Nov 11, 10:35 PM ESTFlash Flood WarningFFCDeKalb, Fulton, Gwinnett6 hr
Nov 12, 12:05 AM ESTRiver Flood WarningFFCForsyth, Fulton6 hr
Nov 12, 12:20 AM ESTSpecial Weather StatementFFCTowns, Union, White40 min
Nov 12, 3:49 AM ESTSpecial Weather StatementFFCHouston, Twiggs41 min
Nov 12, 4:13 AM ESTFlash Flood WarningFFCGreene, Oglethorpe, Putnam6 hr
Nov 12, 4:16 AM ESTFlash Flood WarningFFCHouston6 hr
Nov 12, 4:27 AM ESTRiver Flood WarningFFCForsyth7 hr
Nov 12, 5:24 AM ESTFlash Flood WarningFFCBaldwin, Hancock6 hr
Nov 12, 6:01 AM ESTFlash Flood WarningFFCTaliaferro, Warren, Wilkes6 hr
Nov 12, 6:03 AM ESTFlash Flood WatchFFCBaldwin, Glascock, Hancock, Jefferson, Taliaferro, Warren and 3 more5 hr
Nov 12, 6:40 AM ESTRiver Flood WarningFFCForsyth, Fulton30 hr

Nearby

Flash Flood Warnings in Georgia, 2020Every flash flood warning in 2020

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.