Alert archive / Florida / Mesoscale Discussions in 2020

Mesoscale Discussion 1874

December 24, 20207 counties in Florida; 7 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Dec 24, 2020, 1:11 PM EST for 7 counties in Florida; 7 counties in Georgia. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Dec 24, 2020, 1:11 PM EST (18:11 UTC)
Expired: Dec 24, 2020, 2:45 PM EST
In force: 94 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 20%

Counties Gadsden County, FL, Jefferson County, FL, Leon County, FL, Liberty County, FL, Madison County, FL, Taylor County, FL, Wakulla County, FL, Brooks County, GA, Colquitt County, GA, Cook County, GA, Grady County, GA, Lanier County, GA, Lowndes County, GA, Thomas County, GA

The radar

The Tallahassee radar (KTLH), 26 km from the middle of the area, began a volume at 18:15 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

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 6.2 hours before the alert went out and 23 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 944 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: 346 m²/s²
0-3 km storm-relative helicity: 416 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
Dec 24, 2:02 AM EST	Mesoscale Discussion	SPC	Escambia, Okaloosa, Santa Rosa	58 min
Dec 24, 2:42 AM EST	Tornado Watch	SPC	Escambia, Okaloosa, Santa Rosa	7 hr
Dec 24, 6:23 AM EST	Mesoscale Discussion	SPC	Bay, Gulf, Walton, Washington	2 hr
Dec 24, 4:28 PM EST	Mesoscale Discussion	SPC	Baker, Bradford, Clay, Columbia, Duval, Gilchrist and 5 more	92 min

Nearby

Mesoscale Discussions in Florida, 2020 Mesoscale Discussions in Georgia, 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.