Alert archive / Mississippi / Mesoscale Discussions in 2017

Mesoscale Discussion 407

April 2, 2017Ashley County, Chicot County, Arkansas; 7 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 2, 2017, 3:31 PM CDT for Ashley County, Chicot County, Arkansas; 7 counties in Mississippi. It was in force for 29 min.

The area

The outline as issued.

The facts

Issued: Apr 2, 2017, 3:31 PM CDT (20:31 UTC)
Expired: Apr 2, 2017, 4:00 PM CDT
In force: 29 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

Counties Ashley County, AR, Chicot County, AR, Carroll County, MS, Holmes County, MS, Humphreys County, MS, Leflore County, MS, Montgomery County, MS, Sunflower County, MS, Washington County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 142 km from the middle of the area, began a volume at 20:34 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.

Tornado Watch 111Apr 2, 4:50 PM CDT

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 8.5 hours before the alert went out and 133 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1500 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 106 m²/s²
0-3 km storm-relative helicity: 131 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.

Issued	Product	Office	Counties	Lasted
Apr 2, 1:34 PM CDT	Tornado Watch PDS	SPC	Ashley, Chicot	7 hr
Apr 2, 12:49 PM CDT	Mesoscale Discussion	SPC	Adams, Amite, Claiborne, Copiah, Franklin, Hinds and 7 more	116 min
Apr 2, 3:08 PM CDT	Mesoscale Discussion	SPC	Amite, Pike, Walthall	3 hr
Apr 2, 4:52 PM CDT	Tornado Watch	SPC	Adams, Amite, Attala, Carroll, Choctaw, Claiborne and 39 more	9 hr
Apr 2, 5:06 PM CDT	Mesoscale Discussion	SPC	Bolivar, Calhoun, Chickasaw, Coahoma, Grenada, Itawamba and 9 more	84 min
Apr 2, 5:26 PM CDT	Severe Thunderstorm Watch	SPC	Calhoun, Chickasaw, Coahoma, Itawamba, Lafayette, Lee and 7 more	3 hr

Nearby

Mesoscale Discussions in Mississippi, 2017 Mesoscale Discussions in Arkansas, 2017 Every 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.