Alert archive / Georgia / Flash Flood Warnings in 2020

Flash Flood Warning 71, NWS Atlanta, GA

November 12, 2020Greene County, Oglethorpe County, Putnam County, Georgia

NWS Atlanta, GA issued this flash flood warning at Nov 12, 2020, 4:13 AM EST for Greene County, Oglethorpe County, Putnam 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
Nov 12, 2020, 4:13 AM EST (09:13 UTC)
Expired
Nov 12, 2020, 10:15 AM EST
In force
6 hr
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

Counties Greene County, GA, Oglethorpe County, GA, Putnam County, GA

The radar

The Robins AFB radar (KJGX), 105 km from the middle of the area, began a volume at 09:12 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, 9.2 hours before the alert went out and 130 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.

625 
WGUS52 KFFC 120913
FFWFFC
GAC133-221-237-121515-
/O.NEW.KFFC.FF.W.0071.201112T0913Z-201112T1515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Peachtree City has issued a

* Flash Flood Warning for...
  Northeastern Putnam County in central Georgia...
  Greene County in east central Georgia...
  South Central Oglethorpe County in northeastern Georgia...

* Until 1015 AM EST Thursday.

* At 413 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...
  Greensboro, Union Point, Woodville, White Plains, Siloam, Maxeys, 
  Reynolds at Lake Oconee, Phoenix, Liberty, Penfield, Veazey, 
  Philomath and Rockville.

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 3354 8326 3358 8325 3360 8323 3371 8319
      3386 8309 3388 8301 3382 8296 3378 8299
      3375 8296 3372 8297 3369 8300 3368 8298
      3347 8306 3340 8312 3335 8318 3332 8324
      3334 8328 3344 8329

FLASH FLOOD...RADAR INDICATED

$$
1 follow-up statement
516 
WGUS72 KFFC 121514 RRA
FFSFFC

Flash Flood Statement
National Weather Service Peachtree City GA
1014 AM EST Thu Nov 12 2020

GAC133-221-237-121524-
/O.EXP.KFFC.FF.W.0071.000000T0000Z-201112T1515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Greene GA-Oglethorpe GA-Putnam GA-
1014 AM EST Thu Nov 12 2020

...FLASH FLOOD WARNING WILL EXPIRE AT 1015 AM EST THIS MORNING FOR 
NORTHEASTERN PUTNAM, GREENE AND SOUTH CENTRAL OGLETHORPE COUNTIES...

The heavy rain has ended. Flash Flooding is no longer expected to 
pose a threat. However, areas that are slow to drain may continue to 
have standing water for the next few hours and some creeks and 
streams will remain high. Motorists are cautioned to remain alert 
for water on roads.

A Flash Flood Watch remains in effect until 1100 AM EST for portions 
of central Georgia and east central Georgia.

LAT...LON 3354 8326 3358 8325 3360 8323 3371 8319
      3386 8309 3388 8301 3382 8296 3378 8299
      3375 8296 3372 8297 3369 8300 3368 8298
      3347 8306 3340 8312 3335 8318 3332 8324
      3334 8328 3344 8329

$$

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, 1:37 AM ESTFlash Flood WarningFFCTowns, White5 hr
Nov 12, 3:49 AM ESTSpecial Weather StatementFFCHouston, Twiggs41 min
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.