Alert archive / Alabama / Flash Flood Warnings in 2017

Flash Flood Warning 18, NWS Birmingham, AL

July 11, 2017Jefferson County, Alabama

NWS Birmingham, AL issued this flash flood warning at Jul 11, 2017, 4:00 PM CDT for Jefferson County, Alabama. It was in force for 2 hr. 2 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 11, 2017, 4:00 PM CDT (21:00 UTC)
Expired: Jul 11, 2017, 6:00 PM CDT
In force: 2 hr
Issued by: NWS Birmingham, AL
Area: Storm-based polygon
Flood severity: None

County Jefferson County, AL

The radar

The Birmingham radar (KBMX), 34 km from the middle of the area, began a volume at 21:01 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 11, 4:10 PM CDT	FLASH FLOOD	Cahaba Heights, AL	CROSSHAVEN DRIVE FLOODED NEAR THE INTERSECTION WITH GREEN VALLEY ROAD. WATER ENTERING SEVERAL BUSINESSES IN THIS AREA.
Jul 11, 4:10 PM CDT	FLASH FLOOD	Cahaba Heights, AL	SEVERAL HOMES FLOODED ON DOLLY RIDGE ROAD BETWEEN GREEN VALLEY ROAD AND CAHABA HEIGHTS 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, 9.0 hours before the alert went out and 33 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: 1383 J/kg
Mixed-layer CIN: -32 J/kg
Mixed-layer LCL: 725 m above ground
0-6 km bulk shear: 7 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: -20 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

930 
WGUS54 KBMX 112100
FFWBMX
ALC073-112300-
/O.NEW.KBMX.FF.W.0018.170711T2100Z-170711T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Birmingham AL
400 PM CDT TUE JUL 11 2017

The National Weather Service in Birmingham has issued a

* Flash Flood Warning for...
  East central Jefferson County in Alabama...

* Until 600 PM CDT

* At 400 PM CDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Flash flooding is expected to
  begin shortly.

* Some locations that will experience flooding include...
  Birmingham, Hoover, Vestavia Hills, Homewood, Mountain Brook,
  Irondale, Cahaba Heights, The Summit, Kingston and Liberty Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

&&

LAT...LON 3352 8670 3350 8668 3346 8669 3342 8675
      3340 8676 3339 8678 3341 8681 3342 8680
      3345 8679 3350 8678 3352 8678 3354 8677
      3354 8675 3353 8672

$$

89^GSatterwhite

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 10, 7:25 PM CDT	Areal Flood Advisory	BMX	Lee	65 min
Jul 10, 7:49 PM CDT	Special Weather Statement	BMX	Lee	56 min
Jul 11, 12:07 PM CDT	Special Weather Statement	BMX	Bullock	23 min
Jul 11, 1:42 PM CDT	Special Weather Statement	BMX	Montgomery	33 min
Jul 11, 1:59 PM CDT	Special Weather Statement	BMX	Montgomery	46 min
Jul 11, 2:39 PM CDT	Areal Flood Advisory	BMX	Montgomery	3 hr
Jul 11, 3:11 PM CDT	Special Weather Statement	BMX	Jefferson	34 min
Jul 11, 3:30 PM CDT	Special Weather Statement	BMX	Jefferson	30 min
Jul 11, 3:42 PM CDT	Areal Flood Advisory	BMX	Jefferson	3 hr
Jul 11, 3:51 PM CDT	Special Weather Statement	BMX	Autauga	24 min
Jul 11, 4:14 PM CDT	Special Weather Statement	BMX	Bibb	31 min
Jul 11, 5:29 PM CDT	Areal Flood Advisory	BMX	Clay, Talladega, Tallapoosa	2 hr

Nearby

Flash Flood Warnings in Alabama, 2017 Every flash flood warning in 2017

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.