Alert archive / Florida / Mesoscale Discussions in 2020

Mesoscale Discussion 419

April 20, 20208 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2020, 8:18 AM EDT for 8 counties in Florida. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Apr 20, 2020, 8:18 AM EDT (12:18 UTC)
Expired: Apr 20, 2020, 9:45 AM EDT
In force: 87 min
Issued by: the Storm Prediction Center

Counties Alachua County, FL, Citrus County, FL, Flagler County, FL, Levy County, FL, Marion County, FL, Putnam County, FL, Saint Johns County, FL, Sumter County, FL

The radar

The Jacksonville radar (KJAX), 143 km from the middle of the area, began a volume at 12:19 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, 0.3 hours before the alert went out and 145 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: 72 J/kg
Mixed-layer CIN: -210 J/kg
Mixed-layer LCL: 1009 m above ground
0-6 km bulk shear: 73 kt
0-1 km storm-relative helicity: 521 m²/s²
0-3 km storm-relative helicity: 806 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

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
Apr 19, 10:39 PM EDT	Tornado Watch	SPC	Escambia, Okaloosa, Santa Rosa	5 hr
Apr 19, 10:53 PM EDT	Mesoscale Discussion	SPC	Gadsden, Holmes, Jackson, Walton, Washington	67 min
Apr 19, 11:13 PM EDT	Tornado Watch	SPC	Bay, Calhoun, Dixie, Franklin, Gadsden, Gulf and 11 more	10 hr
Apr 20, 1:52 AM EDT	Mesoscale Discussion	SPC	Alachua, Baker, Bradford, Clay, Columbia, Duval and 6 more	83 min
Apr 20, 2:19 AM EDT	Tornado Watch	SPC	Alachua, Baker, Bradford, Clay, Columbia, Duval and 9 more	9 hr
Apr 20, 6:19 AM EDT	Mesoscale Discussion	SPC	Alachua, Baker, Bradford, Citrus, Clay, Columbia and 16 more	86 min
Apr 20, 7:02 AM EDT	Severe Thunderstorm Watch	SPC	Brevard, Citrus, Hardee, Hernando, Hillsborough, Lake and 11 more	8 hr
Apr 20, 11:06 AM EDT	Mesoscale Discussion	SPC	Brevard, Hardee, Hernando, Hillsborough, Indian River, Lake and 10 more	114 min
Apr 20, 2:00 PM EDT	Mesoscale Discussion	SPC	DeSoto, Hardee, Highlands, Indian River, Manatee, Okeechobee and 4 more	90 min

Nearby

Mesoscale Discussions in Florida, 2020 Every mesoscale discussion in 2020

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.