Alert archive / Florida / Mesoscale Discussions in 2018

Mesoscale Discussion 271

April 15, 201810 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2018, 4:42 PM EDT for 10 counties in Florida. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued: Apr 15, 2018, 4:42 PM EDT (20:42 UTC)
Expired: Apr 15, 2018, 5:45 PM EDT
In force: 63 min
Issued by: the Storm Prediction Center

Counties Broward County, FL, Collier County, FL, DeSoto County, FL, Glades County, FL, Hardee County, FL, Hendry County, FL, Highlands County, FL, Monroe County, FL, Okeechobee County, FL, Palm Beach County, FL

The radar

The Miami radar (KAMX), 126 km from the middle of the area, began a volume at 20:45 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

Miami, FL (KMFL), launched 12:00Z, 8.7 hours before the alert went out and 116 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: 698 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 889 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 75 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 14, 10:27 PM EDT	Mesoscale Discussion	SPC	Escambia, Santa Rosa	93 min
Apr 14, 11:58 PM EDT	Tornado Watch	SPC	Bay, Calhoun, Gulf, Holmes, Jackson, Walton and 1 more	8 hr
Apr 15, 2:45 AM EDT	Mesoscale Discussion	SPC	Bay, Calhoun, Gulf, Holmes, Jackson, Walton and 1 more	2 hr
Apr 15, 6:42 AM EDT	Mesoscale Discussion	SPC	Bay, Calhoun, Gulf, Jackson	93 min
Apr 15, 9:34 AM EDT	Mesoscale Discussion	SPC	Alachua, Baker, Bradford, Columbia, Gilchrist, Hamilton and 4 more	86 min
Apr 15, 10:12 AM EDT	Tornado Watch	SPC	Alachua, Baker, Bradford, Citrus, Clay, Columbia and 22 more	8 hr
Apr 15, 12:18 PM EDT	Mesoscale Discussion	SPC	Hardee, Hillsborough, Manatee, Polk	57 min
Apr 15, 2:30 PM EDT	Mesoscale Discussion	SPC	Clay, Duval, Lake, Manatee, Polk, Putnam and 1 more	90 min

Nearby

Mesoscale Discussions in Florida, 2018 Every 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.