Alert archive / Georgia / Mesoscale Discussions in 2018

Mesoscale Discussion 158

March 20, 2018Nassau County, Florida; 29 counties in Georgia; 12 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Mar 20, 2018, 12:05 PM EDT for Nassau County, Florida; 29 counties in Georgia; 12 counties in South Carolina. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued
Mar 20, 2018, 12:05 PM EDT (16:05 UTC)
Expired
Mar 20, 2018, 1:00 PM EDT
In force
55 min
Issued by
the Storm Prediction Center
Chance of a watch
95%
All 42 counties

Nassau County, FL, Appling County, GA, Atkinson County, GA, Bacon County, GA, Brantley County, GA, Bryan County, GA, Bulloch County, GA, Camden County, GA, Candler County, GA, Charlton County, GA, Chatham County, GA, Clinch County, GA, Coffee County, GA, Echols County, GA, Effingham County, GA, Evans County, GA, Glynn County, GA, Jeff Davis County, GA, Lanier County, GA, Liberty County, GA, Long County, GA, Lowndes County, GA, McIntosh County, GA, Montgomery County, GA, Pierce County, GA, Screven County, GA, Tattnall County, GA, Toombs County, GA, Ware County, GA, Wayne County, GA, Allendale County, SC, Bamberg County, SC, Beaufort County, SC, Berkeley County, SC, Charleston County, SC, Clarendon County, SC, Colleton County, SC, Dorchester County, SC, Georgetown County, SC, Hampton County, SC, Jasper County, SC, Williamsburg County, SC

The radar

The Charleston,SC radar (KCLX), 70 km from the middle of the area, began a volume at 16:07 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, 4.1 hours before the alert went out and 151 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 2018-03-20Temperature 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, Charleston AFB, SC at 12:00Z on 2018-03-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 270 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1495 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
270 m²/s²
0-3 km storm-relative helicity
356 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
Mar 20, 9:50 AM EDTMesoscale DiscussionSPCAlachua, Baker, Bradford, Citrus, Clay, Columbia and 21 more55 min
Mar 20, 10:24 AM EDTTornado WatchSPCAlachua, Baker, Bradford, Brevard, Citrus, Clay and 34 more9 hr
Mar 20, 1:00 PM EDTMesoscale DiscussionSPCAlachua, Baker, Bradford, Citrus, Clay, Columbia and 28 more60 min
Mar 20, 4:16 PM EDTMesoscale DiscussionSPCAlachua, Baker, Bradford, Citrus, Clay, Columbia and 28 more89 min
Mar 19, 8:45 PM EDTMesoscale DiscussionSPCBaldwin, Bartow, Bibb, Butts, Carroll, Chattooga and 40 more60 min
Mar 19, 9:08 PM EDTTornado WatchSPCBaldwin, Barrow, Bartow, Bibb, Butts, Carroll and 48 more7 hr
Mar 19, 9:51 PM EDTMesoscale DiscussionSPCCarroll, Douglas, Haralson, Paulding, Polk84 min
Mar 20, 12:32 AM EDTMesoscale DiscussionSPCBulloch, Burke, Candler, Columbia, Effingham, Jenkins and 2 more88 min
Mar 20, 1:51 AM EDTSevere Thunderstorm WatchSPCBryan, Bulloch, Burke, Candler, Chatham, Columbia and 16 more4 hr
Mar 20, 2:36 AM EDTMesoscale DiscussionSPCBaldwin, Bibb, Crawford, Glascock, Harris, Jefferson and 12 more84 min
Mar 20, 4:54 AM EDTMesoscale DiscussionSPCBryan, Bulloch, Candler, Chatham, Effingham, Emanuel and 12 more96 min
Mar 20, 12:43 PM EDTTornado WatchSPCAppling, Bacon, Brantley, Bryan, Bulloch, Charlton and 13 more7 hr
Mar 20, 2:48 PM EDTMesoscale DiscussionSPCBrantley, Bryan, Camden, Charlton, Chatham, Clinch and 9 more87 min
Mar 20, 6:10 PM EDTMesoscale DiscussionSPCChatham, Glynn, McIntosh65 min

Nearby

Mesoscale Discussions in Georgia, 2018Mesoscale Discussions in South Carolina, 2018Mesoscale Discussions in Florida, 2018Every mesoscale discussion in 2018

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.