Alert archive / Georgia / Mesoscale Discussions in 2017

Mesoscale Discussion 646

May 4, 2017Duval County, Nassau County, Florida; 35 counties in Georgia; Allendale County, Hampton County, Jasper County, South Carolina

The Storm Prediction Center issued this mesoscale discussion at May 4, 2017, 12:48 PM EDT for Duval County, Nassau County, Florida; 35 counties in Georgia; Allendale County, Hampton County, Jasper County, South Carolina. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 4, 2017, 12:48 PM EDT (16:48 UTC)
Expired
May 4, 2017, 3:15 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 40 counties

Duval County, FL, Nassau County, FL, Appling County, GA, Atkinson County, GA, Bacon County, GA, Ben Hill County, GA, Berrien 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, Emanuel County, GA, Evans County, GA, Glynn County, GA, Jeff Davis County, GA, Jenkins County, GA, Lanier County, GA, Liberty County, GA, Long County, GA, McIntosh County, GA, Montgomery County, GA, Pierce County, GA, Screven County, GA, Tattnall County, GA, Telfair County, GA, Toombs County, GA, Treutlen County, GA, Ware County, GA, Wayne County, GA, Wheeler County, GA, Allendale County, SC, Hampton County, SC, Jasper County, SC

The radar

The Jacksonville radar (KJAX), 123 km from the middle of the area, began a volume at 16:48 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 nearest sounding before it

Jacksonville, FL (KJAX), launched 12:00Z, 4.8 hours before the alert went out and 121 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, Jacksonville, FL at 12:00Z on 2017-05-04Temperature 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, Jacksonville, FL at 12:00Z on 2017-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 131 square meters per square second.193958Sfc1 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
1390 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
131 m²/s²
0-3 km storm-relative helicity
119 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
May 4, 8:27 AM EDTMesoscale DiscussionSPCCalhoun, Franklin, Gadsden, Gulf, Jefferson, Leon and 4 more3 hr
May 4, 3:15 PM EDTMesoscale DiscussionSPCCitrus, Dixie, Gilchrist, Hernando, Hillsborough, Levy and 4 more3 hr
May 4, 7:16 PM EDTMesoscale DiscussionSPCBeaufort, Berkeley, Charleston, Colleton, Dorchester, Jasper89 min

Nearby

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