Alert archive / Georgia / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 315, NWS Atlanta, GA

August 1, 2012Forsyth County, Gwinnett County, Hall County, Georgia

NWS Atlanta, GA issued this severe thunderstorm warning at Aug 1, 2012, 4:23 PM EDT for Forsyth County, Gwinnett County, Hall County, Georgia. It was in force for 52 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 1, 2012, 4:23 PM EDT (20:23 UTC)
Expired: Aug 1, 2012, 5:15 PM EDT
In force: 52 min
Issued by: NWS Atlanta, GA
Area: Storm-based polygon

Counties Forsyth County, GA, Gwinnett County, GA, Hall County, GA

The radar

The Atlanta radar (KFFC), 96 km from the middle of the area, began a volume at 20:23 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.

What was reported inside it

Time	Report	Where	Remark
Aug 1, 4:37 PM EDT	TSTM WND DMG	Cumming, GA	FORSYTH EMA RELAYED A REPORT OF TREES DOWN ON HOUSES...POWERLINES DOWN...STREET LIGHTS AND STOPLIGHTS DOWNED BY THUNDERSTORM WIND ACROSS THE COUNTY.
Aug 1, 4:47 PM EDT	HAIL 0.75	3 Ssw Cumming, GA

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 8.4 hours before the alert went out and 92 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1144 J/kg
Mixed-layer CIN: -68 J/kg
Mixed-layer LCL: 595 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 97 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

920 
WUUS52 KFFC 012023
SVRFFC
GAC117-135-139-012115-
/O.NEW.KFFC.SV.W.0315.120801T2023Z-120801T2115Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
423 PM EDT WED AUG 1 2012

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  FORSYTH COUNTY IN NORTH CENTRAL GEORGIA
  NORTHERN GWINNETT COUNTY IN NORTH CENTRAL GEORGIA
  SOUTHWESTERN HALL COUNTY IN NORTH CENTRAL GEORGIA

* UNTIL 515 PM EDT

* AT 419 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZED HAIL...AND
  DAMAGING WINDS UP TO 60 MPH.  THIS STORM WAS LOCATED NEAR
  CUMMING...MOVING SOUTH AT 15 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  FLOWERY BRANCH...REST HAVEN...BUFORD...SUGAR HILL...SUWANEE AND
  DULUTH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE
ENOUGH TO BE STRUCK BY LIGHTNING.

IF YOU SEE WIND DAMAGE...HAIL OR FLOODING...WAIT UNTIL THE STORM HAS
PASSED...AND THEN CALL THE NATIONAL WEATHER SERVICE TOLL FREE AT 1 8
6 6 7 6 3 4 4 6 6. YOU CAN ALSO TWEET YOUR REPORT USING HASHTAG GAWX.

&&

LAT...LON 3415 8379 3413 8382 3407 8384 3391 8414
      3403 8417 3403 8416 3403 8414 3405 8410
      3407 8418 3427 8424 3432 8403
TIME...MOT...LOC 2024Z 342DEG 12KT 3420 8410

$$

1 follow-up statement

178 
WWUS52 KFFC 012108
SVSFFC

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
508 PM EDT WED AUG 1 2012

GAC139-012118-
/O.CAN.KFFC.SV.W.0315.000000T0000Z-120801T2115Z/
HALL GA-
508 PM EDT WED AUG 1 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN HALL COUNTY IS
CANCELLED...

THE SEVERE THUNDERSTORM HAS WEAKENED AND MOVED OUT OF THE AREA AND 
NO LONGER POSES A THREAT TO HALL COUNTY.


LAT...LON 3411 8400 3401 8397 3392 8413 3398 8416
      3400 8415 3403 8417 3403 8414 3405 8410
      3407 8418 3419 8422 3420 8412
TIME...MOT...LOC 2108Z 342DEG 12KT 3407 8415

$$

GAC117-135-012115-
/O.CON.KFFC.SV.W.0315.000000T0000Z-120801T2115Z/
FORSYTH GA-GWINNETT GA-
508 PM EDT WED AUG 1 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM EDT
FOR CENTRAL GWINNETT AND SOUTH CENTRAL FORSYTH COUNTIES...

AT 505 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZED
HAIL...AND DAMAGING WINDS UP TO 60 MPH. THIS STORM WAS LOCATED NEAR 
BROOKWOOD...MOVING SOUTH AT 15 MPH. THIS STORM HAS SHOWN A WEAKENING 
TREND AND IF THIS CONTINUES...A NEW WARNING WILL NOT BE ISSUED.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
PLEASANT HILL...SUWANEE AND DULUTH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU SEE WIND DAMAGE...HAIL OR FLOODING...WAIT UNTIL THE STORM HAS
PASSED...AND THEN CALL THE NATIONAL WEATHER SERVICE TOLL FREE AT 1 8
6 6 7 6 3 4 4 6 6. YOU CAN ALSO TWEET YOUR REPORT USING HASHTAG GAWX.

&&

LAT...LON 3411 8400 3401 8397 3392 8413 3398 8416
      3400 8415 3403 8417 3403 8414 3405 8410
      3407 8418 3419 8422 3420 8412
TIME...MOT...LOC 2108Z 342DEG 12KT 3407 8415

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 31, 8:41 PM EDT	Special Weather Statement	FFC	Catoosa, Walker, Whitfield	64 min
Jul 31, 10:51 PM EDT	Special Weather Statement	FFC	Towns, Union	24 min
Jul 31, 11:18 PM EDT	Special Weather Statement	FFC	Lumpkin, Towns, Union, White	27 min
Aug 1, 3:33 PM EDT	Special Weather Statement	FFC	Chattooga	57 min
Aug 1, 3:51 PM EDT	Severe Thunderstorm Warning	FFC	Chattooga, Floyd	39 min
Aug 1, 4:16 PM EDT	Special Weather Statement	FFC	Forsyth	44 min
Aug 1, 4:21 PM EDT	Special Weather Statement	FFC	Catoosa, Whitfield	39 min
Aug 1, 4:28 PM EDT	Special Weather Statement	FFC	Floyd	47 min
Aug 1, 4:48 PM EDT	Severe Thunderstorm Warning	FFC	Floyd	42 min
Aug 1, 4:57 PM EDT	Special Weather Statement	FFC	Gordon, Murray	33 min
Aug 1, 5:10 PM EDT	Special Weather Statement	FFC	Dawson	50 min
Aug 1, 5:13 PM EDT	Severe Thunderstorm Warning	FFC	Gilmer, Gordon, Murray, Pickens	47 min
Aug 1, 6:05 PM EDT	Special Weather Statement	FFC	Gilmer, Pickens	40 min
Aug 1, 6:17 PM EDT	Special Weather Statement	FFC	Dooly	28 min
Aug 1, 6:19 PM EDT	Special Weather Statement	FFC	Dade, Walker	41 min
Aug 1, 6:26 PM EDT	Special Weather Statement	FFC	Henry, Rockdale	49 min
Aug 1, 6:49 PM EDT	Severe Thunderstorm Warning	FFC	Chattooga, Walker	41 min
Aug 1, 7:23 PM EDT	Severe Thunderstorm Warning	FFC	Chattooga, Walker	52 min
Aug 1, 7:39 PM EDT	Special Weather Statement	FFC	Fannin, Towns, Union	51 min

Nearby

Severe Thunderstorm Warnings in Georgia, 2012 Every severe thunderstorm warning in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.