Alert archive / Florida / Mesoscale Discussions in 2024

Mesoscale Discussion 421

April 11, 20249 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2024, 12:45 PM EDT for 9 counties in Florida. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 11, 2024, 12:45 PM EDT (16:45 UTC)
Expired: Apr 11, 2024, 2:45 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Tornado watch 104

Counties Flagler County, FL, Hillsborough County, FL, Lake County, FL, Orange County, FL, Pasco County, FL, Pinellas County, FL, Seminole County, FL, Sumter County, FL, Volusia County, FL

The radar

The Tampa radar (KTBW), 94 km from the middle of the area, began a volume at 16:49 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

Tampa Bay, FL (KTBW), launched 12:00Z, 4.8 hours before the alert went out and 94 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: 111 J/kg
Mixed-layer CIN: -62 J/kg
Mixed-layer LCL: 691 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 39 m²/s²
0-3 km storm-relative helicity: 120 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.

Issued	Product	Office	Counties	Lasted
Apr 11, 1:58 AM EDT	Mesoscale Discussion	SPC	Bay, Calhoun, Franklin, Gadsden, Gulf, Jefferson and 3 more	2 hr
Apr 11, 6:54 AM EDT	Mesoscale Discussion	SPC	Baker, Bradford, Columbia, Dixie, Gilchrist, Hamilton and 5 more	2 hr
Apr 11, 7:32 AM EDT	Tornado Watch	SPC	Alachua, Baker, Bradford, Citrus, Clay, Columbia and 24 more	7 hr
Apr 11, 10:33 AM EDT	Mesoscale Discussion	SPC	Alachua, Bradford, Citrus, Clay, Duval, Flagler and 13 more	117 min
Apr 11, 1:54 PM EDT	Mesoscale Discussion	SPC	Flagler, Lake, Orange, Polk, Seminole, Volusia	96 min

Nearby

Mesoscale Discussions in Florida, 2024 Every mesoscale discussion in 2024

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.