Alert archive / Alabama / Flash Flood Warnings in 2011

Flash Flood Warning 38, NWS Birmingham, AL

July 21, 2011Walker County, Alabama

NWS Birmingham, AL issued this flash flood warning at Jul 21, 2011, 8:06 AM CDT for Walker County, Alabama. It was in force for 3 hr. 1 report 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
Jul 21, 2011, 8:06 AM CDT (13:06 UTC)
Expired
Jul 21, 2011, 11:00 AM CDT
In force
3 hr
Issued by
NWS Birmingham, AL
Area
Storm-based polygon
Flood severity
None

County Walker County, AL

The radar

The Birmingham radar (KBMX), 81 km from the middle of the area, began a volume at 13:07 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

TimeReportWhereRemark
Jul 21, 8:30 AM CDTFLASH FLOODOakman, ALSEVERAL ROADWAYS IN AND NEAR OAKMAN WERE TEMPORARILY FLOODED WITH SEVERAL INCHES OF FLOWING WATER OVER THE ROAD.

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

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 1.1 hours before the alert went out and 80 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, Birmingham, AL at 12:00Z on 2011-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 493 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, Birmingham, AL at 12:00Z on 2011-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -8 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
493 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
661 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
-8 m²/s²
0-3 km storm-relative helicity
9 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.

910 
WGUS54 KBMX 211306
FFWBMX
ALC127-211600-
/O.NEW.KBMX.FF.W.0038.110721T1306Z-110721T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BIRMINGHAM AL
806 AM CDT THU JUL 21 2011

THE NATIONAL WEATHER SERVICE IN BIRMINGHAM HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL WALKER COUNTY IN ALABAMA...

* UNTIL 1100 AM CDT

* AT 805 AM CDT...NATIONAL WEATHER SERVICE INDICATED SLOW MOVING     
  THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED AREA.     
  RAINFALL ESTIMATES ARE 2 TO 4 INCHES OVER THE PAST 3 HOURS WITH AN 
  ADDITIONAL 1 TO 2 INCHES OVER THE NEXT 3 HOURS AS ADDITIONAL       
  STORMS MOVE THROUGH THE AREA.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  CORDOVA...JASPER...BELOIT...LYNNS PARK...OAKMAN...PARRISH...ROCKY
  HOLLOW...SIPSEY AND SMITH DAM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

TO REPORT SEVERE WEATHER...
CALL 1-800-856-0758.

LAT...LON 3392 8708 3390 8708 3390 8701 3386 8698
      3386 8696 3384 8696 3380 8696 3363 8741
      3366 8743 3369 8743 3369 8745 3379 8753
      3397 8713

$$
1 follow-up statement
678 
WGUS74 KBMX 211449
FFSBMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
949 AM CDT THU JUL 21 2011

ALC127-211600-
/O.CON.KBMX.FF.W.0038.000000T0000Z-110721T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WALKER AL-
949 AM CDT THU JUL 21 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR CENTRAL WALKER COUNTY
UNTIL 1100 AM CDT...

AT 948 AM CDT...ALTHOUGH MUCH OF THE HEAVY RAIN HAS DIMINISHED 
ACROSS CENTRAL WALKER COUNTY...RUNOFF FROM THE PREVIOUS STORMS WILL 
CONTINUE FOR AN HOUR OR SO. RADAR ESTIMATED A FEW LOCATIONS RECEIVED 
2 TO 4 INCHES OF RAIN IN A SHORT PERIOD THIS MORNING. 

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLASH FLOODING INCLUDE...
CORDOVA...JASPER...BELOIT...LYNNS PARK...OAKMAN...PARRISH...ROCKY
HOLLOW...SIPSEY AND SMITH DAM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 3392 8708 3390 8708 3390 8701 3386 8698
      3386 8696 3384 8696 3380 8696 3363 8741
      3366 8743 3369 8743 3369 8745 3379 8753
      3397 8713

$$

75

The office that day

Everything else NWS Birmingham, AL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 21, 3:17 AM CDTAreal Flood AdvisoryBMXClay, Randolph, St. Clair, Shelby, Talladega118 min
Jul 21, 3:35 AM CDTFlash Flood WarningBMXClay, Talladega3 hr
Jul 21, 4:04 AM CDTAreal Flood AdvisoryBMXJefferson, St. Clair, Walker3 hr
Jul 21, 4:30 AM CDTFlash Flood WarningBMXJefferson4 hr
Jul 21, 5:19 AM CDTAreal Flood AdvisoryBMXCalhoun, Clay, Cleburne, Randolph, Talladega116 min
Jul 21, 7:00 AM CDTAreal Flood AdvisoryBMXFayette, Lamar, Walker3 hr
Jul 21, 7:19 AM CDTFlash Flood WarningBMXSt. Clair3 hr
Jul 21, 8:46 AM CDTFlash Flood WarningBMXWalker3 hr

Nearby

Flash Flood Warnings in Alabama, 2011Every flash flood warning in 2011

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.