Alert archive / Alabama / Special Weather Statements in 2017

Special Weather Statement, NWS Birmingham, AL

August 9, 2017Chilton County, Alabama

NWS Birmingham, AL issued this special weather statement at Aug 9, 2017, 6:21 PM CDT for Chilton County, Alabama. It was in force for 24 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 9, 2017, 6:21 PM CDT (23:21 UTC)
Expired: Aug 9, 2017, 6:45 PM CDT
In force: 24 min
Issued by: NWS Birmingham, AL

County Chilton County, AL

The radar

The Birmingham radar (KBMX), 21 km from the middle of the area, began a volume at 23:25 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 12:00Z, 11.4 hours before the alert went out and 22 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: 324 J/kg
Mixed-layer CIN: -35 J/kg
Mixed-layer LCL: 555 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 80 m²/s²
0-3 km storm-relative helicity: 87 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

255 
WWUS84 KBMX 092321
SPSBMX

Special Weather Statement
National Weather Service Birmingham AL
621 PM CDT WED AUG 9 2017
 
ALZ025-035-092345-
Chilton AL-Shelby AL-
621 PM CDT WED AUG 9 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN CHILTON AND
SOUTHEASTERN SHELBY COUNTIES UNTIL 645 PM CDT...

At 621 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Lay Lake Dam to near Ashby. Movement was
east at 20 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
Calera, Montevallo, Columbiana, Jemison, Wilton, Lay Lake Dam,
Shelby, Minooka Park, Spring Creek At Lay Lake, Beeswax Creek Park,
Waxahatchee At Lay Lake, Alabama 4h Center and AlL145 And CR 46.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3309 8688 3318 8650 3316 8648 3315 8648
      3313 8647 3312 8647 3312 8648 3309 8651
      3307 8651 3306 8652 3300 8652 3299 8651
      3293 8652 3294 8688
TIME...MOT...LOC 2321Z 257DEG 19KT 3304 8655 3298 8684 

$$

89^GSatterwhite

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 5:54 PM CDT	Areal Flood Advisory	BMX	Chambers, Lee	2 hr
Aug 9, 6:09 PM CDT	Special Weather Statement	BMX	Lee	36 min
Aug 9, 6:18 PM CDT	Special Weather Statement	BMX	Bibb	27 min
Aug 9, 6:45 PM CDT	Special Weather Statement	BMX	Russell	30 min

Nearby

Special Weather Statements in Alabama, 2017 Every special weather statement 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.