Alert archive / Florida / Mesoscale Discussions in 2018

Mesoscale Discussion 928

June 28, 201823 counties in Florida; 11 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Jun 28, 2018, 7:22 PM EDT for 23 counties in Florida; 11 counties in Georgia. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
Jun 28, 2018, 7:22 PM EDT (23:22 UTC)
Expired
Jun 28, 2018, 8:45 PM EDT
In force
83 min
Issued by
the Storm Prediction Center
Chance of a watch
5%
All 34 counties

Alachua County, FL, Baker County, FL, Bradford County, FL, Clay County, FL, Columbia County, FL, Dixie County, FL, Duval County, FL, Gadsden County, FL, Gilchrist County, FL, Hamilton County, FL, Jefferson County, FL, Lafayette County, FL, Leon County, FL, Levy County, FL, Madison County, FL, Marion County, FL, Nassau County, FL, Putnam County, FL, Saint Johns County, FL, Suwannee County, FL, Taylor County, FL, Union County, FL, Wakulla County, FL, Brooks County, GA, Camden County, GA, Charlton County, GA, Clinch County, GA, Decatur County, GA, Echols County, GA, Grady County, GA, Lanier County, GA, Lowndes County, GA, Thomas County, GA, Ware County, GA

The radar

The Moody AFB radar (KVAX), 80 km from the middle of the area, began a volume at 23:24 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

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 11.4 hours before the alert went out and 115 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, Tallahassee Rgnl, FL at 12:00Z on 2018-06-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1691 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, Tallahassee Rgnl, FL at 12:00Z on 2018-06-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 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
1691 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
734 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
11 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
Jun 28, 5:34 PM EDTMesoscale DiscussionSPCEscambia, Holmes, Okaloosa, Santa Rosa, Walton86 min
Jun 28, 5:59 PM EDTSevere Thunderstorm WatchSPCBay, Calhoun, Escambia, Gulf, Holmes, Jackson and 4 more7 hr
Jun 28, 11:22 AM EDTMesoscale DiscussionSPCBartow, Carroll, Catoosa, Chattooga, Cherokee, Cobb and 14 more113 min
Jun 28, 11:46 AM EDTSevere Thunderstorm WatchSPCBaldwin, Bartow, Bibb, Butts, Carroll, Chattooga and 49 more8 hr
Jun 28, 2:07 PM EDTMesoscale DiscussionSPCCarroll, Chattahoochee, Coweta, Crawford, Crisp, Dooly and 21 more113 min

Nearby

Mesoscale Discussions in Florida, 2018Mesoscale Discussions in Georgia, 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.