Alert archive / Alabama / Mesoscale Discussions in 2012

Mesoscale Discussion 1661

July 31, 20129 counties in Alabama; 8 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Jul 31, 2012, 7:47 AM CDT for 9 counties in Alabama; 8 counties in Florida. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued: Jul 31, 2012, 7:47 AM CDT (12:47 UTC)
Expired: Jul 31, 2012, 8:45 AM CDT
In force: 58 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Covington County, AL, Escambia County, AL, Geneva County, AL, Monroe County, AL, Washington County, AL, Wilcox County, AL, Calhoun County, FL, Escambia County, FL, Holmes County, FL, Jackson County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL

The radar

The Eglin Afb radar (KEVX), 108 km from the middle of the area, began a volume at 12:48 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, 0.8 hours before the alert went out and 231 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: 374 J/kg
Mixed-layer CIN: -98 J/kg
Mixed-layer LCL: 636 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 116 m²/s²
0-3 km storm-relative helicity: 271 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 30, 11:21 PM CDT	Mesoscale Discussion	SPC	Fayette, Franklin, Greene, Jefferson, Lamar, Marion and 5 more	114 min
Jul 31, 1:02 AM CDT	Mesoscale Discussion	SPC	Bibb, Blount, Chilton, Cullman, Fayette, Hale and 10 more	88 min
Jul 31, 1:23 AM CDT	Severe Thunderstorm Watch	SPC	Autauga, Bibb, Bullock, Chambers, Chilton, Clay and 19 more	6 hr
Jul 31, 5:48 AM CDT	Mesoscale Discussion	SPC	Autauga, Bibb, Bullock, Chambers, Chilton, Clay and 19 more	57 min
Jul 31, 11:01 AM CDT	Mesoscale Discussion	SPC	Baldwin, Clarke, Mobile, Washington	59 min

Nearby

Mesoscale Discussions in Alabama, 2012 Mesoscale Discussions in Florida, 2012 Every mesoscale discussion 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.