Alert archive / Georgia / Mesoscale Discussions in 2017

Mesoscale Discussion 420

April 3, 201730 counties in Georgia; 11 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 3, 2017, 1:42 PM EDT for 30 counties in Georgia; 11 counties in South Carolina. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued: Apr 3, 2017, 1:42 PM EDT (17:42 UTC)
Expired: Apr 3, 2017, 2:45 PM EDT
In force: 63 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 41 counties

Appling County, GA, Bryan County, GA, Bulloch County, GA, Burke County, GA, Candler County, GA, Columbia County, GA, Dodge County, GA, Effingham County, GA, Emanuel County, GA, Evans County, GA, Glascock County, GA, Jeff Davis County, GA, Jefferson County, GA, Jenkins County, GA, Johnson County, GA, Laurens County, GA, Liberty County, GA, Lincoln County, GA, Long County, GA, McDuffie County, GA, Montgomery County, GA, Richmond County, GA, Screven County, GA, Tattnall County, GA, Telfair County, GA, Toombs County, GA, Treutlen County, GA, Warren County, GA, Washington County, GA, Wheeler County, GA, Aiken County, SC, Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Calhoun County, SC, Edgefield County, SC, Hampton County, SC, Lexington County, SC, McCormick County, SC, Orangeburg County, SC, Saluda County, SC

The radar

The Robins AFB radar (KJGX), 102 km from the middle of the area, began a volume at 17:44 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

Charleston AFB, SC (KCHS), launched 12:00Z, 5.7 hours before the alert went out and 213 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: 1059 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 41 m²/s²
0-3 km storm-relative helicity: 47 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 3, 10:07 AM EDT	Mesoscale Discussion	SPC	Baldwin, Banks, Barrow, Bibb, Bleckley, Bulloch and 54 more	83 min
Apr 3, 10:25 AM EDT	Mesoscale Discussion	SPC	Baker, Butts, Calhoun, Carroll, Chattahoochee, Clay and 30 more	65 min
Apr 3, 10:50 AM EDT	Severe Thunderstorm Watch	SPC	Baker, Baldwin, Barrow, Ben Hill, Berrien, Bibb and 92 more	7 hr
Apr 3, 2:07 PM EDT	Tornado Watch	SPC	Appling, Atkinson, Bacon, Baldwin, Bleckley, Bryan and 45 more	6 hr
Apr 3, 6:41 PM EDT	Mesoscale Discussion	SPC	Chatham, McIntosh	64 min
Apr 3, 4:00 PM EDT	Mesoscale Discussion	SPC	Berkeley, Chesterfield, Clarendon, Darlington, Dillon, Dorchester and 8 more	90 min
Apr 3, 4:36 PM EDT	Severe Thunderstorm Watch	SPC	Beaufort, Berkeley, Charleston, Colleton, Darlington, Dillon and 7 more	4 hr

Nearby

Mesoscale Discussions in Georgia, 2017 Mesoscale Discussions in South Carolina, 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.