Alert archive / Georgia / Mesoscale Discussions in 2012

Mesoscale Discussion 1642

July 29, 201253 counties in Georgia; 16 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Jul 29, 2012, 2:35 PM EDT for 53 counties in Georgia; 16 counties in South Carolina. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued
Jul 29, 2012, 2:35 PM EDT (18:35 UTC)
Expired
Jul 29, 2012, 3:30 PM EDT
In force
55 min
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 69 counties

Appling County, GA, Atkinson County, GA, Bacon County, GA, Ben Hill County, GA, Berrien County, GA, Bleckley County, GA, Brantley County, GA, Bryan County, GA, Bulloch County, GA, Burke County, GA, Candler County, GA, Chatham County, GA, Coffee County, GA, Crisp County, GA, Dodge County, GA, Dooly County, GA, Dougherty County, GA, Effingham County, GA, Emanuel County, GA, Evans County, GA, Glascock County, GA, Houston County, GA, Irwin County, GA, Jeff Davis County, GA, Jefferson County, GA, Jenkins County, GA, Johnson County, GA, Laurens County, GA, Lee County, GA, Liberty County, GA, Long County, GA, McIntosh County, GA, Montgomery County, GA, Pierce County, GA, Pulaski County, GA, Richmond County, GA, Screven County, GA, Sumter County, GA, Tattnall County, GA, Telfair County, GA, Terrell County, GA, Tift County, GA, Toombs County, GA, Treutlen County, GA, Turner County, GA, Twiggs County, GA, Ware County, GA, Washington County, GA, Wayne County, GA, Wheeler County, GA, Wilcox County, GA, Wilkinson County, GA, Worth County, GA, Aiken County, SC, Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Beaufort County, SC, Berkeley County, SC, Calhoun County, SC, Clarendon County, SC, Colleton County, SC, Dorchester County, SC, Georgetown County, SC, Hampton County, SC, Jasper County, SC, Orangeburg County, SC, Sumter County, SC, Williamsburg County, SC

The radar

The Charleston,SC radar (KCLX), 76 km from the middle of the area, began a volume at 18:36 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 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, 6.6 hours before the alert went out and 177 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, Charleston AFB, SC at 12:00Z on 2012-07-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2597 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, Charleston AFB, SC at 12:00Z on 2012-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 63 square meters per square second.1939Sfc1 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
2597 J/kg
Mixed-layer CIN
-47 J/kg
Mixed-layer LCL
738 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
63 m²/s²
0-3 km storm-relative helicity
38 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 29, 2:55 PM EDTSevere Thunderstorm WatchSPCAppling, Atkinson, Bacon, Bleckley, Bryan, Bulloch and 25 more5 hr
Jul 29, 6:36 PM EDTMesoscale DiscussionSPCAppling, Bacon, Brantley, Bryan, Bulloch, Camden and 12 more24 min

Nearby

Mesoscale Discussions in Georgia, 2012Mesoscale Discussions in South Carolina, 2012Every mesoscale discussion in 2012

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.