Alert archive / Georgia / Flash Flood Watches in 2017

Flash Flood Watch 3, NWS Atlanta, GA

May 21, 20174 counties in Georgia

NWS Atlanta, GA issued this flash flood watch at May 21, 2017, 4:03 AM EDT for 4 counties in Georgia. It was in force for 11 hr.

The area

The counties it named.

The facts

Issued
May 21, 2017, 4:03 AM EDT (08:03 UTC)
Expired
May 21, 2017, 3:09 PM EDT
In force
11 hr
Issued by
NWS Atlanta, GA
Flood severity
None

Counties Lumpkin County, GA, Towns County, GA, Union County, GA, White County, GA

The radar

The Greer radar (KGSP), 151 km from the middle of the area, began a volume at 08:05 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, 8.1 hours before the alert went out and 163 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 2017-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 86 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 2017-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 101 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
86 J/kg
Mixed-layer CIN
-265 J/kg
Mixed-layer LCL
1583 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
101 m²/s²
0-3 km storm-relative helicity
91 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

753 
WGUS62 KFFC 210803
FFAFFC

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Peachtree City GA
403 AM EDT Sun May 21 2017

GAZ008-009-015-016-220000-
/O.NEW.KFFC.FF.A.0003.170521T0803Z-170522T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Union-Towns-Lumpkin-White-
Including the cities of Dahlonega and Cleveland
403 AM EDT Sun May 21 2017

...FLASH FLOOD WATCH IN EFFECT THROUGH THIS EVENING...

The National Weather Service in Peachtree City has issued a

* Flash Flood Watch for portions of north central Georgia and 
  northeast Georgia...including the following areas...in north 
  central Georgia...Lumpkin and Union. In northeast Georgia... 
  Towns and White. 

* Through this evening

* Abundant moisture combined with an upper level storm system will
  lead to widespread showers and thunderstorms today. Heavy rain
  will be possible at times over the watch area...especially this
  morning through early afternoon. 1 to 2 inches has already
  fallen over portions of Lumpkin county with around an inch
  elsewhere. Additional rainfall amounts of 1 to 2 inches are
  possible today.

* Flooding in low lying and flood prone areas will be likely,
  especially in urban areas and the Interstate 20 corridor. In 
  addition, creeks, streams and rivers may overflow their banks. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that conditions may develop that lead
to flash flooding. Flash flooding is a very dangerous situation.

You should monitor later forecasts and be prepared to take action
should Flash Flood Warnings be issued.

&&

$$
2 follow-up statements
214 
WGUS62 KFFC 211427
FFAFFC

Flood Watch
National Weather Service Peachtree City GA
1027 AM EDT Sun May 21 2017



GAZ008-009-015-016-212230-
/O.CON.KFFC.FF.A.0003.000000T0000Z-170522T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Union-Towns-Lumpkin-White-
Including the cities of Dahlonega and Cleveland
1027 AM EDT Sun May 21 2017

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 8 PM EDT THIS
EVENING...

The Flash Flood Watch continues for

* Portions of north central Georgia and northeast Georgia... 
  including the following areas...in north central Georgia... 
  Lumpkin and Union. In northeast Georgia...Towns and White. 

* Until 8 PM EDT this evening

* Abundant moisture combined with an upper level storm system 
  will lead to widespread showers and thunderstorms today. Heavy 
  rain will be possible at times over the watch area... 
  especially this morning through early afternoon. 1 to 2 inches 
  has already fallen over portions of Lumpkin county with around 
  an inch elsewhere. Additional rainfall amounts of 1 to 2 
  inches are possible today. 

* Flooding in low lying and flood prone areas will be likely, 
  especially in urban areas and the Interstate 20 corridor. In 
  addition, creeks, streams and rivers may overflow their banks. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that conditions may develop that lead
to flash flooding. Flash flooding is a very dangerous situation.

You should monitor later forecasts and be prepared to take action
should Flash Flood Warnings be issued.

&&

$$
294 
WGUS62 KFFC 211909
FFAFFC

Flood Watch
National Weather Service Peachtree City GA
309 PM EDT Sun May 21 2017


GAZ008-009-015-016-212015-
/O.CAN.KFFC.FF.A.0003.000000T0000Z-170522T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Union-Towns-Lumpkin-White-
Including the cities of Dahlonega and Cleveland
309 PM EDT Sun May 21 2017

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of north central Georgia and
northeast Georgia has been cancelled. Rainfall rates have lessened
considerably and the heaviest activity has moved off to the east. 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 8:15 PM EDTSpecial Weather StatementFFCCatoosa, Walker30 min
May 20, 8:18 PM EDTSpecial Weather StatementFFCGordon27 min
May 20, 8:40 PM EDTSpecial Weather StatementFFCWhitfield35 min
May 20, 9:11 PM EDTAreal Flood WarningFFCWhitfield6 hr
May 21, 12:31 AM EDTSpecial Weather StatementFFCClayton, Cobb, DeKalb, Fayette, Forsyth, Fulton and 1 more44 min
May 21, 1:32 AM EDTSpecial Weather StatementFFCBarrow, DeKalb, Forsyth, Gwinnett, Rockdale43 min
May 21, 2:18 AM EDTSpecial Weather StatementFFCBanks, Barrow, Gwinnett, Hall, Jackson, Newton and 2 more42 min
May 21, 2:19 AM EDTSpecial Weather StatementFFCHeard, Troup26 min
May 21, 2:58 AM EDTSpecial Weather StatementFFCCarroll, Coweta, Heard, Meriwether, Troup47 min
May 21, 3:02 AM EDTSpecial Weather StatementFFCBanks, Barrow, Butts, Clarke, Jackson, Jasper and 4 more58 min

Nearby

Flash Flood Watches in Georgia, 2017Every flash flood watch 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.