Alert archive / Florida / Mesoscale Discussions in 2018

Mesoscale Discussion 1680

December 1, 201810 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Dec 1, 2018, 10:45 AM CST for 10 counties in Florida. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Dec 1, 2018, 10:45 AM CST (16:45 UTC)
Expired: Dec 1, 2018, 12:45 PM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Bay County, FL, Calhoun County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Jackson County, FL, Liberty County, FL, Okaloosa County, FL, Walton County, FL, Washington County, FL

The radar

The Eglin Afb radar (KEVX), 73 km from the middle of the area, began a volume at 16:45 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 watches that followed

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

Tornado Watch 433Dec 1, 11:15 AM CST

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 4.8 hours before the alert went out and 204 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: 976 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 259 m²/s²
0-3 km storm-relative helicity: 531 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 1, 4:31 AM CST	Mesoscale Discussion	SPC	Escambia, Okaloosa, Santa Rosa	59 min
Dec 1, 11:16 AM CST	Tornado Watch	SPC	Bay, Calhoun, Escambia, Franklin, Gadsden, Gulf and 9 more	7 hr
Dec 1, 1:35 PM CST	Mesoscale Discussion	SPC	Bay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 7 more	85 min
Dec 1, 3:38 PM CST	Mesoscale Discussion	SPC	Bay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 7 more	97 min
Dec 1, 5:53 PM CST	Tornado Watch	SPC	Bay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 11 more	9 hr

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.