A deepening upper-level trough along with a moist and moderately unstable air mass resulted in scattered strong to severe thunderstorms each afternoon and evening, mainly along a stationary frontal boundary across north Georgia. 5 to 5 inches of rain in localized areas, producing flash flooding during the evening of August 20th.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS FFC wrote it up.
A deepening upper-level trough along with a moist and moderately unstable air mass resulted in scattered strong to severe thunderstorms each afternoon and evening, mainly along a stationary frontal boundary across north Georgia. Slow-moving and training storms produced 2.5 to 5 inches of rain in localized areas, producing flash flooding during the evening of August 20th.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Atlanta, GA wrote its last area forecast discussion before the first event at Aug 19, 6:49 AM EST, 5 hours 22 minutes earlier.
Area Forecast Discussion National Weather Service Peachtree City GA 749 AM EDT Wed Aug 19 2020 .UPDATE... 12z Aviation update below. Baker && .PREV DISCUSSION... /Issued 427 AM EDT Wed Aug 19 2020/ SHORT TERM /Today through Thursday/... As upper trough amplifies with axis west of the area today, some enhanced forcing for convection will be in place along with a stalled boundary across some central portions of the CWA and possible influence of another sfc boundary near the NW. The greater deep layer moisture will be in the northern and western majority so have trended likely pops to this part of the area with chance pops elsewhere in the east. Some strong to isolated severe intensity of diurnally aided storms are possible with marginal conditional instability. Progged trough has even more amplification and the axis shifts farther southward into the Gulf, so region has increased SW fetch and moisture advection for Thursday. Have likely to categorical pops accordingly and a bit greater chance for more organized/stronger convection in central or eastern GA as SW flow/shear increases. SPC does have parts of central GA in a Day 2 Marginal Risk for severe potential. For temps, highs today look to be near climo norms in the upper 80s to low 90s for most areas, then limited to about 4-5 degrees below norm (low to mid 80s) for Thursday given aforementioned increased moisture/convective coverage. Baker && .LONG TERM /Thursday Night through Tuesday/... The long term period will begin with the deep upper-level trough centered over the ArkLaMiss, placing Georgia within a region of deep layer southwesterly flow and broad ascent. Ascent will be maximized on Friday and Saturday thanks to a somewhat-abnormal- for-summer 250 mb jet streak across the area. The GFS and ECMWF are progging a 500 mb cutoff low associated with the trough on Friday and Saturday, with vort maxima advecting northward out of the base of the trough as an extra source of lift for showers and thunderstorms both days. Upper-level dynamics and PWATs of 1.5" to 2" across much of the CWA on Friday will be conducive for numerous showers and thunderstorms with locally heavy rainfall and water-loaded downdrafts. The trough will begin to lift on Saturday as it is forced northward by the Bermuda High expanding across the Eastern Seaboard. PWATs across the northern CWA will decrease a bit as a result, but Saturday will still bring numerous showers and thunderstorms. By Sunday, much of the CWA will be under the influence of the Bermuda High, though some moisture advection will continue around its periphery. Models are hinting at some drier air working into the CWA on the backside of the lifting trough on Sunday, so I have chance PoPs across much of north and central Georgia. Moisture will linger into early next week, though upper-level flow looks to be unimpressive, so I have chance PoPs for Monday and Tuesday. Uncertainty remains concerning the impact that Disturbance 1 (currently in the eastern Caribbean Sea) will have on the CWA. The NHC is forecasting the disturbance to become a tropical depression late this week or this weekend, so it will need to be monitored over the coming days. Martin && .AVIATION... 12Z Update... Initial VFR conditions for most sites (MVFR or lower cigs/vsbys possible near KAHN). Otherwise cu field today near 3500-5000 ft and increased SHRA/TSRA chances after 19z (decreasing later in evening). Possible MVFR or lower cigs for Thursday morning and could have MVFR vsbys for sites other than near KATL. Winds mainly east to SE 4-6 kts aside from any VRB gusts with TSRA. //ATL Confidence...12Z Update... Medium on Thursday morning cigs. High on all else. Baker && .PRELIMINARY POINT TEMPS/POPS... Athens 90 69 83 67 / 50 40 80 60 Atlanta 90 69 84 68 / 70 60 80 60 Blairsville 82 63 76 63 / 70 50 80 60 Cartersville 91 68 84 68 / 70 60 80 60 Columbus 93 70 87 69 / 70 50 80 60 Gainesville 87 68 80 66 / 60 50 80 60 Macon 92 69 87 68 / 60 50 80 60 Rome 91 68 85 68 / 70 50 80 60 Peachtree City 90 68 84 67 / 70 60 80 60 Vidalia 90 71 88 70 / 40 40 60 60 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...Baker LONG TERM....Martin AVIATION...Baker
Hazardous Weather Outlook National Weather Service Peachtree City GA 1224 PM EDT Wed Aug 19 2020 GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086- 089>098-102>113-201630- Baldwin-Banks-Barrow-Bartow-Bibb-Bleckley-Butts-Carroll-Catoosa- Chattahoochee-Chattooga-Cherokee-Clarke-Clayton-Cobb-Coweta- Crawford-Crisp-Dade-Dawson-DeKalb-Dodge-Dooly-Douglas-Emanuel- Fannin-Fayette-Floyd-Forsyth-Gilmer-Glascock-Gordon-Greene- Gwinnett-Hall-Hancock-Haralson-Harris-Heard-Henry-Houston-Jackson- Jasper-Jefferson-Johnson-Jones-Lamar-Laurens-Lumpkin-Macon- Madison-Marion-Meriwether-Monroe-Montgomery-Morgan-Murray- Muscogee-Newton-North Fulton-Oconee-Oglethorpe-Paulding-Peach- Pickens-Pike-Polk-Pulaski-Putnam-Rockdale-Schley-South Fulton- Spalding-Stewart-Sumter-Talbot-Taliaferro-Taylor-Telfair-Toombs- Towns-Treutlen-Troup-Twiggs-Union-Upson-Walker-Walton-Warren- Washington-Webster-Wheeler-White-Whitfield-Wilcox-Wilkes- Wilkinson- 1224 PM EDT Wed Aug 19 2020 This Hazardous Weather Outlook is for portions of North and Central Georgia. .DAY ONE...This Afternoon and Tonight... Scattered to numerous thunderstorms are forecast this afternoon and evening across north and central Georgia. Some thunderstorms may linger overnight. A few storms could be strong with an isolated severe storm possible. The main threats will be locally heavy rainfall, strong to damaging winds, and cloud-to-ground lightning. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday... Numerous thunderstorms are expected Thursday through Saturday across much of the forecast area. Scattered thunderstorms are forecast Sunday through Tuesday. A few storms could be strong to severe each day, with strong to damaging winds, frequent lightning, small hail, and locally heavy rainfall. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed through tonight.
Special Weather Statement
National Weather Service Peachtree City GA
744 AM EDT Wed Aug 19 2020
GAZ005>007-191215-
Gilmer GA-Murray GA-Fannin GA-
744 AM EDT Wed Aug 19 2020
...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN GILMER...
NORTHEASTERN MURRAY AND NORTHWESTERN FANNIN COUNTIES UNTIL 815 AM
EDT...
At 743 AM EDT...a strong thunderstorm was over Conasauga Lake, or 10
miles northeast of Chatsworth...moving northeast at 15 mph.
HAZARD...Up to 40 mph wind...frequent cloud to ground lightning
and heavy rain.
IMPACT...Expect minor damage to tree limbs and blowing around of
light...unsecured objects. Heavy rain may cause temporary
street flooding especially in poor drainage areas.
Some locations in the path of this storm include
Cisco, Conasauga Lake, Tennga, Cohutta Wilderness and Jones Mill.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
People outdoors should seek shelter immediately. If you can hear
thunder...you are close enough to be struck by lightning. Motorists
should slow down and be prepared for possible loss of control due to
hydroplaning.
LAT...LON 3485 8446 3479 8467 3499 8477 3499 8450
TIME...MOT...LOC 1143Z 245DEG 11KT 3488 8464
WIND...40MPHSpecial Weather Statement
National Weather Service Peachtree City GA
1255 PM EDT Wed Aug 19 2020
GAZ001-002-011-191730-
Chattooga GA-Walker GA-Dade GA-
1255 PM EDT Wed Aug 19 2020
...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN CHATTOOGA...WESTERN
WALKER AND DADE COUNTIES UNTIL 130 PM EDT...
At 1254 PM EDT...a line of strong thunderstorms was along a line
extending from near Stephensville to near Sulpher Springs...and
moving south at 5 mph.
HAZARD...40 to 50 mph wind...frequent cloud to ground lightning
and heavy rain.
IMPACT...Expect minor damage to tree limbs and blowing around of
light...unsecured objects. Heavy rain may cause temporary
street flooding especially in poor drainage areas.
Some locations in the path of these storms include
Trenton, Stephensville, Rising Fawn, New England, Morganville,
Hooker, Cloudland Canyon State Park, Cooper Heights, Cole City and
Wildwood.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
People outdoors should seek shelter immediately. If you can hear
thunder...you are close enough to be struck by lightning. Motorists
should slow down and be prepared for possible loss of control due to
hydroplaning.
LAT...LON 3498 8538 3454 8535 3458 8553 3486 8559
3498 8560
TIME...MOT...LOC 1654Z 339DEG 4KT 3492 8559 3465 8554
WIND...50MPHThe Northeast Alabama radar (KHTX), 53 km away, was scanning. The volume nearest the first event began at 17:10 UTC.
11 thunderstorm wind, 5 flash flood, 3 hail. Local standard time, as filed.
The Dade County Emergency Manager reported a tree blown down onto power lines in the 600 block of Lake Hills Drive.
The public reported a tree blown down in a yard along Emerald Drive.
The public reported a couple of trees blown down along Retreat Ridge SE.
The Jackson County Emergency Manager reported several trees blown down from Pendergrass to Jefferson and Arcade.
The Cherokee County 911 center reported a tree blown down onto power lines near the intersection of Knox Bridge Highway and Upper Sweetwater Trail.
The public reported hail the size of quarters near the intersection of Sandy Plains Road and Scufflegrit Road.
The public reported hail the size of nickels near Milton High School.
The Cobb County 911 center reported a couple of trees blown down in the northeastern portion of the county.
A report of hail the size of quarters near the intersection of Old Canton Road and Sewell Mill Road was received over social media.
The Jasper County 911 center reported a tree blown down along Post Road.
The Paulding County Emergency Manager reported numerous trees and some power lines blown down across the county.
The public reported several large pecan trees blown down.
The Emergency Manager reported water over Red Hill Road. Radar estimates indicate that 3 to 4 inches of rain quickly fell over the area.
The Emergency Manager reported water over Fire Tower Road. Radar estimates indicate that 3 to 4 inches of rain quickly fell over the area, resulting in the flooding.
The public reported a few trees blown down from Alpharetta to Milton.
The public reported a power line blown down near the intersection of Goodson Cemetery Road and Wilderness Camp Road SE.
A state official reported water over the roadway along Highway 382, Knight Road and Sunlight Road. Radar estimates indicate that 3 to 5 inches of rain quickly fell over the area.
A state official reported water over Bray Road. Radar estimates indicate that 2.5 to 4 inches of rain occurred over the area, causing the flooding.
The Emergency Manager reported flash flooding at the 2500 block of Knight Road. Increased streamflow in Flat Creek caused the erosion of soil under the road surface, requiring repairs. Radar estimates indicate that 2.5 to 4 inches of rain quickly fell over the area, causing the creek to rise.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Georgia in 2020Every state in 2020This day in weather historyWarnings in Georgia, August 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 917208, 917209, 917210, 917211, 917212, 917205, 917206, 917213, 917207, 917214, 917215, 917216, 919030, 919034, 917217, 917218, 919058, 919060, 919061.