Alert archive / Georgia / Flash Flood Warnings in 2009

Flash Flood Warning 1, NWS Atlanta, GA

March 27, 2009Gwinnett County, Georgia

NWS Atlanta, GA issued this flash flood warning at Mar 27, 2009, 4:45 PM EDT for Gwinnett County, Georgia. It was in force for 4 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
Mar 27, 2009, 4:45 PM EDT (20:45 UTC)
Expired
Mar 27, 2009, 9:00 PM EDT
In force
4 hr
Issued by
NWS Atlanta, GA
Area
Storm-based polygon
Flood severity
None

County Gwinnett County, GA

The radar

The Atlanta radar (KFFC), 85 km from the middle of the area, began a volume at 20:44 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 12:00Z, 8.8 hours before the alert went out and 82 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 12:00Z on 2009-03-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 56 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 12:00Z on 2009-03-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 97 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
56 J/kg
Mixed-layer CIN
-32 J/kg
Mixed-layer LCL
487 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
97 m²/s²
0-3 km storm-relative helicity
212 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
WGUS52 KFFC 272045
FFWFFC
GAC135-280245-
/O.NEW.KFFC.FF.W.0001.090327T2045Z-090328T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
445 PM EDT FRI MAR 27 2009

THE NATIONAL WEATHER SERVICE IN PEACHTREE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  GWINNETT COUNTY IN NORTH CENTRAL GEORGIA

* UNTIL 1045 PM EDT

* AT 441 PM EDT...THE STAGE ON THE ALCOVY RIVER NEAR LAWRENCEVILLE 
WAS 9.2 FEET. FLOOD STAGE IS 9.0 FEET. THE ALCOVY RIVER WILL FALL 
BELOW FLOOD STAGE BY 1045 PM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING. 
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY. 
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE 
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS 
SWIFTLY FLOWING WATERS...OR WATERS OF UNKNOWN DEPTH...ON FOOT OR IN 
AN AUTOMOBILE.

IF YOU SEE SIGNIFICANT FLOODING CALL THE NATIONAL WEATHER SERVICE
TOLL FREE AT 1 8 6 6 7 6 3 4 4 6 6.

&&

LAT...LON 3410 8386 3410 8383 3400 8386 3393 8380
      3375 8403 3375 8404 3393 8427 3397 8427
      3400 8423 3400 8419 3403 8416 3405 8412
      3409 8412 3418 8406

$$
2 follow-up statements
000 
WGUS72 KFFC 272247
FFSFFC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
647 PM EDT FRI MAR 27 2009

GAC135-280245-
/O.CON.KFFC.FF.W.0001.000000T0000Z-090328T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GWINNETT GA-
647 PM EDT FRI MAR 27 2009

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1045 PM EDT FOR
GWINNETT COUNTY...

AT 642 PM EDT...THE STAGE ON THE ALCOVY RIVER NEAR LAWRENCEVILE WAS 
9.5 FEET. FLOOD STAGE IS 9.0 FEET. THE ALCOVY RIVER SHOULD CREST 
NEAR 9.7 FEET AROUND 8 PM AND THEN FALL BELOW FLOOD STAGE BY 1045 PM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS...OR WATERS OF UNKNOWN DEPTH...ON FOOT OR IN
AN AUTOMOBILE.

IF YOU SEE SIGNIFICANT FLOODING CALL THE NATIONAL WEATHER SERVICE
TOLL FREE AT 1 8 6 6 7 6 3 4 4 6 6.

&&

LAT...LON 3410 8386 3410 8383 3400 8386 3393 8380
      3375 8403 3375 8404 3393 8427 3397 8427
      3400 8423 3400 8419 3403 8416 3405 8412
      3409 8412 3418 8406

$$
000 
WGUS72 KFFC 280100
FFSFFC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
800 PM EDT FRI MAR 27 2009

GAC135-280108-
/O.CAN.KFFC.FF.W.0001.000000T0000Z-090328T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GWINNETT GA-
800 PM EDT FRI MAR 27 2009

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR GWINNETT COUNTY...

* AT 845 PM THE STAGE ON THE ALCOVY RIVER NEAR LAWRENCEVILLE WAS 8.8 
FEET. FLOOD STAGE IS 9.0 FEET. THE ALCOVY RIVER WILL CONTINUE TO 
FALL AND REMAIN BELOW FLOOD STAGE.


IF YOU SEE SIGNIFICANT FLOODING CALL THE NATIONAL WEATHER SERVICE
TOLL FREE AT 1 8 6 6 7 6 3 4 4 6 6.

LAT...LON 3410 8386 3410 8383 3400 8386 3393 8380
      3375 8403 3375 8404 3393 8427 3397 8427
      3400 8423 3400 8419 3403 8416 3405 8412
      3409 8412 3418 8406

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 27, 3:54 PM EDTRiver Flood WarningFFCClarke, Greene, Oconee4 days

Nearby

Flash Flood Warnings in Georgia, 2009Every flash flood warning in 2009

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.