Alert archive / Alabama / Flash Flood Watches in 2009
Flash Flood Watch 18, NWS Birmingham, AL
NWS Birmingham, AL issued this flash flood watch at Oct 11, 2009, 9:20 PM CDT for 18 counties in Alabama. It took effect at Oct 12, 2009, 4:00 AM CDT. It was in force for 12 hr.
The area
The counties it named.
The facts
- Issued
- Oct 11, 2009, 9:20 PM CDT (02:20 UTC)
- In effect from
- Oct 12, 2009, 4:00 AM CDT
- Expired
- Oct 12, 2009, 4:00 PM CDT
- In force
- 12 hr
- Issued by
- NWS Birmingham, AL
- Flood severity
- None
Counties Blount County, AL, Calhoun County, AL, Cherokee County, AL, Clay County, AL, Cleburne County, AL, Etowah County, AL, Fayette County, AL, Jefferson County, AL, Lamar County, AL, Marion County, AL, Pickens County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL
The radar
The Birmingham radar (KBMX), 57 km from the middle of the area, began a volume at 02:22 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.
The nearest sounding before it
Birmingham, AL (KBMX), launched 00:00Z, 2.3 hours before the alert went out and 56 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.
- Mixed-layer CAPE
- 9 J/kg
- Mixed-layer CIN
- -68 J/kg
- Mixed-layer LCL
- 720 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 82 m²/s²
- 0-3 km storm-relative helicity
- 148 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this flash flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Birmingham, AL wrote its last area forecast discussion before this flash flood watch went out at Oct 11, 6:44 PM CDT, 2 hours 36 minutes earlier.
Area forecast discussion, Oct 11, 6:44 PM CDT, 2 hours 36 minutes before
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</html>Hazardous weather outlook, Oct 11, 7:23 PM CDT, 1 hour 57 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE BIRMINGHAM AL 723 PM CDT SUN OCT 11 2009 ALZ011>015-017>050-130023- AUTAUGA-BARBOUR-BIBB-BLOUNT-BULLOCK-CALHOUN-CHAMBERS-CHEROKEE- CHILTON-CLAY-CLEBURNE-COOSA-DALLAS-ELMORE-ETOWAH-FAYETTE-GREENE-HALE- JEFFERSON-LAMAR-LEE-LOWNDES-MACON-MARENGO-MARION-MONTGOMERY-PERRY- PICKENS-PIKE-RANDOLPH-RUSSELL-SHELBY-ST CLAIR-SUMTER-TALLADEGA- TALLAPOOSA-TUSCALOOSA-WALKER-WINSTON- 723 PM CDT SUN OCT 11 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE COUNTIES SERVED BY THE NATIONAL WEATHER SERVICE OFFICE IN BIRMINGHAM. .DAY ONE...TONIGHT. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE AFTER 3 AM ACROSS THE NORTHWEST SECTIONS AS LOW PRESSURE APPROACHES FROM THE WEST. PONDING OF WATER ON ROADWAYS AND MINOR FLOODING IN POOR DRAINAGE AREAS WILL BE POSSIBLE. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY. A WARM FRONT IS EXPECTED TO LIFT NORTHWARD ACROSS CENTRAL ALABAMA DURING THE EARLY MORNING HOURS ON MONDAY. STRONG TO POSSIBLY SEVERE STORMS COULD DEVELOP ALONG AND SOUTH OF THIS FRONT FROM AROUND 10 AM UNTIL 8 PM. THE MAIN THREATS WITH ANY STORM DEVELOPMENT WILL BE GUSTY WINDS AND LOCALLY HEAVY RAINFALL. HOWEVER...ISOLATED TORNADOES MAY ALSO BE POSSIBLE WITH THIS SYSTEM...PLEASE CONTINUE TO MONITOR FOR UPDATED INFORMATION OF THIS DEVELOPING WEATHER PATTERN. IN ADDITION...LOCALLY HEAVY RAINFALL WILL BE POSSIBLE ALONG AND NORTH OF THE INTERSTATE 20 CORRIDOR WITH RAINFALL AMOUNTS OF 1 TO 2 INCHES POSSIBLE. A STRONG COLD FRONT IS EXPECTED TO MOVE ACROSS CENTRAL ALABAMA THURSDAY INTO EARLY FRIDAY. SEVERE THUNDERSTORMS WILL BE POSSIBLE ALONG AND AHEAD OF THE FRONT. CONTINUE TO MONITOR THIS PRODUCT FOR FURTHER UPDATES TO THE TIMING...STRENGTH...AND FORECAST CONFIDENCE OF THIS DEVELOPING WEATHER SYSTEM. .SPOTTER INFORMATION STATEMENT... ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT MAY BE NEEDED ON MONDAY AND AGAIN ON THURSDAY INTO EARLY FRIDAY. KSL
The office that day
Everything else NWS Birmingham, AL issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 12, 2:30 AM CDT | Areal Flood Advisory | BMX | Jefferson | 2 hr |
| Oct 12, 3:22 AM CDT | Flash Flood Warning | BMX | Lamar | 3 hr |
| Oct 12, 4:43 AM CDT | Areal Flood Advisory | BMX | Walker | 2 hr |
| Oct 12, 5:47 AM CDT | Flash Flood Warning | BMX | Jefferson | 4 hr |
| Oct 12, 8:10 AM CDT | Tornado Warning | BMX | Randolph | 20 min |
| Oct 12, 8:15 AM CDT | Flash Flood Warning | BMX | Etowah | 3 hr |
| Oct 12, 9:43 AM CDT | Flash Flood Warning | BMX | Randolph | 2 hr |
| Oct 12, 10:02 AM CDT | River Flood Warning | BMX | Bibb, Jefferson, Shelby | 13 hr |
| Oct 12, 10:31 AM CDT | River Flood Warning | BMX | Greene, Hale, Marengo, Pickens, Sumter | 6 days |
| Oct 12, 10:44 AM CDT | Flash Flood Warning | BMX | Lamar | 4 hr |
Nearby
Flash Flood Watches in Alabama, 2009Every flash flood watch 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.