Alert archive / Florida / Mesoscale Discussions in 2017

Mesoscale Discussion 822

May 24, 20179 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at May 24, 2017, 3:45 AM EDT for 9 counties in Florida. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 24, 2017, 3:45 AM EDT (07:45 UTC)
Expired: May 24, 2017, 5:45 AM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Alachua County, FL, Bradford County, FL, Clay County, FL, Duval County, FL, Gilchrist County, FL, Levy County, FL, Marion County, FL, Putnam County, FL, Saint Johns County, FL

The radar

The Jacksonville radar (KJAX), 89 km from the middle of the area, began a volume at 07:46 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.

Tornado Watch 261May 24, 6:55 AM EDT

The nearest sounding before it

Jacksonville, FL (KJAX), launched 00:00Z, 7.8 hours before the alert went out and 91 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 924 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 1107 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 260 m²/s²
0-3 km storm-relative helicity: 303 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 10.7

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.

Issued	Product	Office	Counties	Lasted
May 24, 6:30 AM EDT	Mesoscale Discussion	SPC	Alachua, Baker, Bradford, Brevard, Citrus, Clay and 33 more	2 hr
May 24, 6:56 AM EDT	Tornado Watch	SPC	Alachua, Baker, Bay, Bradford, Calhoun, Citrus and 30 more	8 hr
May 24, 10:26 AM EDT	Mesoscale Discussion	SPC	Alachua, Baker, Bay, Bradford, Calhoun, Citrus and 32 more	94 min
May 24, 11:03 AM EDT	Tornado Watch	SPC	Baker, Columbia, Duval, Hamilton, Nassau, Suwannee	10 hr
May 24, 12:54 PM EDT	Mesoscale Discussion	SPC	Alachua, Bradford, Brevard, Broward, Charlotte, Citrus and 30 more	2 hr
May 24, 2:10 PM EDT	Mesoscale Discussion	SPC	Baker, Columbia, Duval, Hamilton, Madison, Nassau and 1 more	95 min
May 24, 2:49 PM EDT	Severe Thunderstorm Watch	SPC	Brevard, Broward, Charlotte, Clay, Collier, DeSoto and 23 more	7 hr
May 24, 5:25 PM EDT	Mesoscale Discussion	SPC	Baker, Columbia, Duval, Hamilton, Madison, Nassau and 2 more	65 min

Nearby

Mesoscale Discussions in Florida, 2017 Every 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.