Alert archive / Alabama / Mesoscale Discussions in 2017

Mesoscale Discussion 570

April 27, 201717 counties in Alabama; 8 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2017, 1:36 AM CDT for 17 counties in Alabama; 8 counties in Mississippi. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued
Apr 27, 2017, 1:36 AM CDT (06:36 UTC)
Expired
Apr 27, 2017, 3:30 AM CDT
In force
114 min
Issued by
the Storm Prediction Center
All 25 counties

Autauga County, AL, Bibb County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Dallas County, AL, Greene County, AL, Hale County, AL, Lowndes County, AL, Marengo County, AL, Monroe County, AL, Perry County, AL, Shelby County, AL, Sumter County, AL, Tuscaloosa County, AL, Washington County, AL, Wilcox County, AL, Clarke County, MS, Forrest County, MS, Greene County, MS, Jasper County, MS, Jones County, MS, Lauderdale County, MS, Perry County, MS, Wayne County, MS

The radar

The Birmingham radar (KBMX), 154 km from the middle of the area, began a volume at 06:36 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, 6.6 hours before the alert went out and 154 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-pSkew-T log-p diagram, Birmingham, AL at 00:00Z on 2017-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Birmingham, AL at 00:00Z on 2017-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 51 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1641 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
86 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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.

IssuedProductOfficeCountiesLasted
Apr 26, 11:02 PM CDTSevere Thunderstorm WatchSPCAutauga, Bibb, Chilton, Coosa, Dallas, Elmore and 16 more6 hr
Apr 27, 9:42 AM CDTMesoscale DiscussionSPCBarbour, Bullock, Coffee, Covington, Dale, Pike and 1 more2 hr
Apr 27, 12:30 PM CDTMesoscale DiscussionSPCBarbour, Russell90 min
Apr 27, 3:23 PM CDTMesoscale DiscussionSPCBarbour, Henry, Lee, Russell97 min
Apr 27, 6:26 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Crenshaw, Pike, Russell64 min
Apr 26, 7:02 PM CDTMesoscale DiscussionSPCAdams, Attala, Carroll, Claiborne, Copiah, Franklin and 14 more88 min
Apr 26, 7:36 PM CDTMesoscale DiscussionSPCAlcorn, Benton, Calhoun, Chickasaw, Clay, Grenada and 12 more84 min
Apr 26, 9:01 PM CDTSevere Thunderstorm WatchSPCAdams, Attala, Choctaw, Claiborne, Clarke, Clay and 29 more5 hr
Apr 26, 11:57 PM CDTMesoscale DiscussionSPCCovington, Jones93 min

Nearby

Mesoscale Discussions in Alabama, 2017Mesoscale Discussions in Mississippi, 2017Every mesoscale discussion 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.