Alert archive / Alabama / Flash Flood Warnings in 2012

Flash Flood Warning 15, NWS Birmingham, AL

July 18, 2012Shelby County, Alabama

NWS Birmingham, AL issued this flash flood warning at Jul 18, 2012, 10:41 AM CDT for Shelby County, Alabama. It was in force for 3 hr. 3 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: Jul 18, 2012, 10:41 AM CDT (15:41 UTC)
Expired: Jul 18, 2012, 1:30 PM CDT
In force: 3 hr
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Flood severity: None

County Shelby County, AL

The radar

The Birmingham radar (KBMX), 9 km from the middle of the area, began a volume at 15:41 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 18, 10:41 AM CDT	FLASH FLOOD	Alabaster, AL	MULTIPLE ROAD CLOSURES IN THE CITY OF ALABASTER. WATER CASCADING OVER ROADWAYS. SOME AREAS 4 TO 6 INCHES DEEP ACROSS ROADWAY. WATER IN LOW LYING AREAS UP TO ONE FOOT DEEP. SEVERAL STRANDED VEHICLES.
Jul 18, 10:45 AM CDT	FLASH FLOOD	2 Ssw Alabaster, AL	THERE WERE 8 HOMES AND 5 CARS THAT WERE FLOODED OUT IN THE AREA BETWEEN THOMPSON ROAD...PACIFIC DRIVE AND CARIBBEAN CIRCLE. THE FLOODING WAS GENERALLY 4 TO 6 FEET IN THE BASEMENTS OF THE HOMES AND WAS A RESULT OF A SMALL DRAINAGE DITCH OVERFLOWING FROM THE EXC
Jul 18, 1:00 PM CDT	HEAVY RAIN 4.34	4 Ssw Alabaster, AL	MEASURED THROUGH 1 PM.

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, 3.7 hours before the alert went out and 8 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: 1162 J/kg
Mixed-layer CIN: -115 J/kg
Mixed-layer LCL: 873 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 18 m²/s²
0-3 km storm-relative helicity: 18 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.

889 
WGUS54 KBMX 181541
FFWBMX
ALC117-181830-
/O.NEW.KBMX.FF.W.0015.120718T1541Z-120718T1830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1041 AM CDT WED JUL 18 2012

THE NATIONAL WEATHER SERVICE IN BIRMINGHAM HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WESTERN SHELBY COUNTY IN ALABAMA...

* UNTIL 130 PM CDT

* AT 1039 AM CDT...NATIONAL WEATHER SERVICE RADAR INDICATED SLOW 
MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED 
AREA. TWO TO THREE INCHES OF RAIN HAS FALLEN ACROSS PORTIONS OF THE 
AREA...AND AN ADDITIONAL ONE TO TWO INCHES IS POSSIBLE DURING THE 
NEXT HOUR.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  ALABASTER...CALERA...HELENA...MONTEVALLO...PELHAM...AMERICAN
  VILLAGE...INDIAN SPRINGS VILLAGE...MAYLENE...OAK MOUNTAIN
  AMPITHEATER...OAK MOUNTAIN STATE PARK...SHELBY COUNTY AIRPORT AND
  UNIVERSITY OF MONTEVALLO.

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 OR TWEET YOUR REPORT USING HASHTAG ALWX

LAT...LON 3340 8671 3309 8657 3309 8691 3327 8693

$$

2 follow-up statements

448 
WGUS74 KBMX 181632
FFSBMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1132 AM CDT WED JUL 18 2012

ALC117-181830-
/O.CON.KBMX.FF.W.0015.000000T0000Z-120718T1830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SHELBY AL-
1132 AM CDT WED JUL 18 2012

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR WESTERN SHELBY COUNTY
UNTIL 130 PM CDT...

AT 1128 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS WITH VERY HEAVY RAINFALL CONTINUED.  FLOODING OF SOME 
ROADS AND STREETS HAS BEEN REPORTED IN THE PELHAM AND ALABASTER 
AREAS...AND A FEW ROADS ARE REPORTED TO HAVE BEEN CLOSED.

RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO 
OCCUR DURING THE NEXT COUPLE OF HOURS. LOW LYING AREAS WITH POOR 
DRAINAGE OR NEAR SMALL CREEKS AND STREAMS WILL BE ESPECIALLY 
SUSCEPTIBLE TO FLOODING.

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 3340 8671 3309 8657 3309 8691 3327 8693

$$

815 
WGUS74 KBMX 181759
FFSBMX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1259 PM CDT WED JUL 18 2012

ALC117-181830-
/O.CON.KBMX.FF.W.0015.000000T0000Z-120718T1830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SHELBY AL-
1259 PM CDT WED JUL 18 2012

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR WESTERN SHELBY COUNTY
UNTIL 130 PM CDT...

AT 1253 PM CDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED THAT 
FLOODING OF SOME STREETS AND ROADWAYS...AS WELL AS A FEW 
HOMES...CONTINUES IN ALABASTER IN AREAS NEAR THOMPSON ROAD AND  
HIGHWAY 119 WITH SOME ROADWAYS STILL CLOSED.  FLOODING ALSO 
CONTINUES ALONG PORTIONS OF BUCK CREEK.

THE HEAVIER RAIN HAS MOVED OUT OF THE AREA...BUT RUNOFF WILL 
CONTINUE FOR THE NEXT FEW HOURS.  ALTHOUGH WATERS ARE BEGINNING TO 
RECEDE...SOME FLOODING WILL PERSIST OVER THE AREA FOR THE NEXT FEW 
HOURS.

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 3340 8671 3309 8657 3309 8691 3327 8693

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 7:52 PM CDT	Special Weather Statement	BMX	Montgomery	38 min
Jul 17, 11:12 PM CDT	Areal Flood Advisory	BMX	Greene	2 hr
Jul 17, 11:48 PM CDT	Special Weather Statement	BMX	Cherokee	42 min
Jul 18, 12:37 AM CDT	Special Weather Statement	BMX	Etowah	38 min
Jul 18, 12:45 AM CDT	Special Weather Statement	BMX	Cherokee	30 min
Jul 18, 1:12 AM CDT	Special Weather Statement	BMX	Etowah	48 min
Jul 18, 6:59 AM CDT	Special Weather Statement	BMX	Randolph	46 min
Jul 18, 10:53 AM CDT	Areal Flood Advisory	BMX	Jefferson	112 min
Jul 18, 11:14 AM CDT	Flash Flood Warning	BMX	Jefferson	88 min
Jul 18, 12:29 PM CDT	Special Weather Statement	BMX	Greene, Sumter	46 min
Jul 18, 12:57 PM CDT	Special Weather Statement	BMX	Fayette	48 min
Jul 18, 1:29 PM CDT	Areal Flood Warning	BMX	Shelby	3 hr
Jul 18, 1:43 PM CDT	Areal Flood Advisory	BMX	Walker, Winston	2 hr
Jul 18, 1:45 PM CDT	Special Weather Statement	BMX	Fayette, Greene	45 min
Jul 18, 1:49 PM CDT	Areal Flood Advisory	BMX	Greene, Hale, Pickens, Tuscaloosa	116 min
Jul 18, 2:04 PM CDT	Areal Flood Advisory	BMX	Fayette, Lamar	116 min
Jul 18, 2:14 PM CDT	Areal Flood Advisory	BMX	Etowah	2 hr

Nearby

Flash Flood Warnings in Alabama, 2012 Every flash flood 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.