Alert archive / Alabama / Flash Flood Warnings in 2011

Flash Flood Warning 37, NWS Birmingham, AL

July 21, 2011St. Clair County, Alabama

NWS Birmingham, AL issued this flash flood warning at Jul 21, 2011, 7:19 AM CDT for St. Clair 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, 7:19 AM CDT (12:19 UTC)
Expired: Jul 21, 2011, 10:30 AM CDT
In force: 3 hr
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Flood severity: None

County St. Clair County, AL

The radar

The Birmingham radar (KBMX), 77 km from the middle of the area, began a volume at 12:22 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
Jul 21, 8:00 AM CDT	FLASH FLOOD	3 S Wattsville, AL	WATER WAS UP OVER A BRIDGE ALONG US HIGHWAY 231 NEAR COAL CITY AND IVY DRIVE.

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, 0.3 hours before the alert went out and 77 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: 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.

021 
WGUS54 KBMX 211219
FFWBMX
ALC115-211530-
/O.NEW.KBMX.FF.W.0037.110721T1219Z-110721T1530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

THE NATIONAL WEATHER SERVICE IN BIRMINGHAM HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL ST. CLAIR COUNTY IN ALABAMA...

* UNTIL 1030 AM CDT

* AT 717 AM CDT...NATIONAL WEATHER SERVICE INDICATED SLOW MOVING     
  THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED AREA.     
  RAINFALL ESTIMATES ARE 1 TO 3 INCHES OVER THE PAST 3 HOURS WITH AN 
  ADDITIONAL 1 TO 2 INCHES OVER THE NEXT 2 HOURS. 

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  ODENVILLE...ARGO...BRANCHVILLE...MARGARET AND RAGLAND.

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 3377 8605 3374 8610 3371 8612 3371 8614
      3367 8615 3370 8618 3369 8621 3365 8617
      3363 8617 3361 8655 3366 8652 3372 8652
      3377 8655 3378 8605

$$

1 follow-up statement

163 
WGUS74 KBMX 211422
FFSBMX

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

ALC115-211530-
/O.CON.KBMX.FF.W.0037.000000T0000Z-110721T1530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ST. CLAIR AL-
922 AM CDT THU JUL 21 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR CENTRAL ST. CLAIR COUNTY
UNTIL 1030 AM CDT...

AT 921 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THAT
SOME FLASH FLOODING WAS OCCURRING NEAR COAL CITY AND US 231. 
ALTHOUGH MUCH OF THE HEAVIER RAIN HAS DIMINISHED...RUNOFF FROM THE 
PREVIOUS STORMS WILL CONTINUE FRO ANOTHER HOUR OR SO.  

SOME LOCATIONS THAT MAY EXPERIENCE FLASH FLOODING 
INCLUDE...ODENVILLE...ARGO...BRANCHVILLE...MARGARET AND RAGLAND.

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 3377 8605 3374 8610 3371 8612 3371 8614
      3367 8615 3370 8618 3369 8621 3365 8617
      3363 8617 3361 8655 3366 8652 3372 8652
      3377 8655 3378 8605

$$

75

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 3:17 AM CDT	Areal Flood Advisory	BMX	Clay, Randolph, St. Clair, Shelby, Talladega	118 min
Jul 21, 3:35 AM CDT	Flash Flood Warning	BMX	Clay, Talladega	3 hr
Jul 21, 4:04 AM CDT	Areal Flood Advisory	BMX	Jefferson, St. Clair, Walker	3 hr
Jul 21, 4:30 AM CDT	Flash Flood Warning	BMX	Jefferson	4 hr
Jul 21, 5:19 AM CDT	Areal Flood Advisory	BMX	Calhoun, Clay, Cleburne, Randolph, Talladega	116 min
Jul 21, 7:00 AM CDT	Areal Flood Advisory	BMX	Fayette, Lamar, Walker	3 hr
Jul 21, 8:06 AM CDT	Flash Flood Warning	BMX	Walker	3 hr
Jul 21, 8:46 AM CDT	Flash Flood Warning	BMX	Walker	3 hr

Nearby

Flash Flood Warnings in Alabama, 2011 Every 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.