Alert archive / Florida / Mesoscale Discussions in 2017

Mesoscale Discussion 453

April 5, 201714 counties in Florida; Charlton County, Echols County, Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 5, 2017, 11:15 PM EDT for 14 counties in Florida; Charlton County, Echols County, Georgia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 5, 2017, 11:15 PM EDT (03:15 UTC)
Expired: Apr 6, 2017, 1:15 AM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 60%

Counties Alachua County, FL, Baker County, FL, Bradford County, FL, Clay County, FL, Columbia County, FL, Duval County, FL, Gilchrist County, FL, Hamilton County, FL, Lafayette County, FL, Madison County, FL, Nassau County, FL, Putnam County, FL, Suwannee County, FL, Union County, FL, Charlton County, GA, Echols County, GA

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 131Apr 6, 12:10 AM EDT

The nearest sounding before it

Jacksonville, FL (KJAX), launched 00:00Z, 3.3 hours before the alert went out and 105 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: 1177 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 1408 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 122 m²/s²
0-3 km storm-relative helicity: 132 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 3.8

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 6, 12:15 AM EDT	Tornado Watch	SPC	Alachua, Baker, Bradford, Citrus, Clay, Columbia and 22 more	6 hr
Apr 6, 3:12 AM EDT	Mesoscale Discussion	SPC	Alachua, Baker, Bradford, Citrus, Clay, Columbia and 25 more	2 hr
Apr 6, 6:10 AM EDT	Mesoscale Discussion	SPC	Hardee, Hillsborough, Lake, Manatee, Orange, Osceola and 4 more	2 hr
Apr 5, 9:58 PM EDT	Tornado Watch	SPC	Bibb, Butts, Chattahoochee, Clayton, Coweta, Crawford and 27 more	3 hr
Apr 5, 11:34 PM EDT	Mesoscale Discussion	SPC	Elbert, Lincoln, Wilkes	56 min
Apr 5, 11:50 PM EDT	Severe Thunderstorm Watch	SPC	Baldwin, Bleckley, Burke, Clarke, Columbia, Elbert and 24 more	6 hr
Apr 6, 2:54 AM EDT	Mesoscale Discussion	SPC	Burke, Columbia, Dodge, Emanuel, Jefferson, Jenkins and 4 more	96 min

Nearby

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