Alert archive / Mississippi / Mesoscale Discussions in 2017

Mesoscale Discussion 566

April 26, 201716 parishes in Louisiana; 20 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 26, 2017, 7:02 PM CDT for 16 parishes in Louisiana; 20 counties in Mississippi. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued
Apr 26, 2017, 7:02 PM CDT (00:02 UTC)
Expired
Apr 26, 2017, 8:30 PM CDT
In force
88 min
Issued by
the Storm Prediction Center
All 36 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Jefferson Davis Parish, LA, LaSalle Parish, LA, Madison Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Landry Parish, LA, Tensas Parish, LA, West Feliciana Parish, LA, Adams County, MS, Attala County, MS, Carroll County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Leflore County, MS, Madison County, MS, Montgomery County, MS, Rankin County, MS, Sharkey County, MS, Warren County, MS, Wilkinson County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 96 km from the middle of the area, began a volume at 00:06 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.

The nearest sounding before it

Jackson, MS (KJAN), launched 00:00Z, 0.0 hours before the alert went out and 86 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, Jackson, MS at 00:00Z on 2017-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 448 joules per kilogram.LCLLFCEL10008507005003002001001 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, Jackson, MS at 00:00Z on 2017-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 113 square meters per square second.19395878Sfc1 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
448 J/kg
Mixed-layer CIN
-135 J/kg
Mixed-layer LCL
1294 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
113 m²/s²
0-3 km storm-relative helicity
161 m²/s²
Significant tornado parameter
0.1
Supercell composite
2.1

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.

IssuedProductOfficeCountiesLasted
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
Apr 27, 1:36 AM CDTMesoscale DiscussionSPCClarke, Forrest, Greene, Jasper, Jones, Lauderdale and 2 more114 min

Nearby

Mesoscale Discussions in Mississippi, 2017Mesoscale Discussions in Louisiana, 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.