Alert archive / Alabama / Mesoscale Discussions in 2018

Mesoscale Discussion 925

June 28, 201827 counties in Alabama; 5 counties in Florida; 18 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jun 28, 2018, 4:34 PM CDT for 27 counties in Alabama; 5 counties in Florida; 18 counties in Mississippi. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued: Jun 28, 2018, 4:34 PM CDT (21:34 UTC)
Expired: Jun 28, 2018, 6:00 PM CDT
In force: 86 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

All 50 counties

Autauga County, AL, Baldwin County, AL, Butler County, AL, Choctaw County, AL, Clarke County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Dallas County, AL, Escambia County, AL, Geneva County, AL, Greene County, AL, Hale County, AL, Henry County, AL, Houston County, AL, Lowndes County, AL, Marengo County, AL, Mobile County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Pike County, AL, Sumter County, AL, Washington County, AL, Wilcox County, AL, Escambia County, FL, Holmes County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Clarke County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Jasper County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Newton County, MS, Noxubee County, MS, Pearl River County, MS, Perry County, MS, Stone County, MS, Wayne County, MS

The radar

The Mobile radar (KMOB), 89 km from the middle of the area, began a volume at 21:38 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 236Jun 28, 5:00 PM CDT

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 9.6 hours before the alert went out and 224 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: 1996 J/kg
Mixed-layer CIN: -52 J/kg
Mixed-layer LCL: 830 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 0 m²/s²
0-3 km storm-relative helicity: 72 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 28, 10:22 AM CDT	Mesoscale Discussion	SPC	Calhoun, Cherokee, Cleburne, DeKalb, Etowah, Jackson and 6 more	113 min
Jun 28, 10:46 AM CDT	Severe Thunderstorm Watch	SPC	Autauga, Barbour, Blount, Bullock, Calhoun, Chambers and 32 more	8 hr
Jun 28, 1:07 PM CDT	Mesoscale Discussion	SPC	Autauga, Barbour, Bibb, Blount, Bullock, Butler and 44 more	113 min
Jun 28, 4:59 PM CDT	Severe Thunderstorm Watch	SPC	Baldwin, Butler, Choctaw, Clarke, Coffee, Conecuh and 18 more	7 hr
Jun 28, 6:22 PM CDT	Mesoscale Discussion	SPC	Alachua, Baker, Bradford, Clay, Columbia, Dixie and 17 more	83 min

Nearby

Mesoscale Discussions in Alabama, 2018 Mesoscale Discussions in Mississippi, 2018 Mesoscale Discussions in Florida, 2018 Every mesoscale discussion in 2018

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.