Alert archive / Georgia / Mesoscale Discussions in 2018

Mesoscale Discussion 265

April 15, 201810 counties in Florida; 23 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2018, 9:34 AM EDT for 10 counties in Florida; 23 counties in Georgia. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
Apr 15, 2018, 9:34 AM EDT (13:34 UTC)
Expired
Apr 15, 2018, 11:00 AM EDT
In force
86 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 33 counties

Alachua County, FL, Baker County, FL, Bradford County, FL, Columbia County, FL, Gilchrist County, FL, Hamilton County, FL, Lafayette County, FL, Nassau County, FL, Suwannee County, FL, Union County, FL, Appling County, GA, Atkinson County, GA, Bacon County, GA, Ben Hill County, GA, Brantley County, GA, Camden County, GA, Charlton County, GA, Clinch County, GA, Coffee County, GA, Echols County, GA, Evans County, GA, Jeff Davis County, GA, Lanier County, GA, Long County, GA, Montgomery County, GA, Pierce County, GA, Tattnall County, GA, Telfair County, GA, Toombs County, GA, Treutlen County, GA, Ware County, GA, Wayne County, GA, Wheeler County, GA

The radar

The Moody AFB radar (KVAX), 48 km from the middle of the area, began a volume at 13:37 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

Jacksonville, FL (KJAX), launched 12:00Z, 1.6 hours before the alert went out and 89 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 2018-04-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 651 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, Jacksonville, FL at 12:00Z on 2018-04-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 147 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
651 J/kg
Mixed-layer CIN
-59 J/kg
Mixed-layer LCL
809 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
147 m²/s²
0-3 km storm-relative helicity
145 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.1

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
Apr 14, 10:27 PM EDTMesoscale DiscussionSPCEscambia, Santa Rosa93 min
Apr 14, 11:58 PM EDTTornado WatchSPCBay, Calhoun, Gulf, Holmes, Jackson, Walton and 1 more8 hr
Apr 15, 2:45 AM EDTMesoscale DiscussionSPCBay, Calhoun, Gulf, Holmes, Jackson, Walton and 1 more2 hr
Apr 15, 6:42 AM EDTMesoscale DiscussionSPCBay, Calhoun, Gulf, Jackson93 min
Apr 15, 10:12 AM EDTTornado WatchSPCAlachua, Baker, Bradford, Citrus, Clay, Columbia and 22 more8 hr
Apr 15, 12:18 PM EDTMesoscale DiscussionSPCHardee, Hillsborough, Manatee, Polk57 min
Apr 15, 2:30 PM EDTMesoscale DiscussionSPCClay, Duval, Lake, Manatee, Polk, Putnam and 1 more90 min
Apr 15, 4:42 PM EDTMesoscale DiscussionSPCBroward, Collier, DeSoto, Glades, Hardee, Hendry and 4 more63 min
Apr 15, 12:13 PM EDTTornado WatchSPCBurke, Columbia, Lincoln, McDuffie, Richmond9 hr

Nearby

Mesoscale Discussions in Georgia, 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.