Alert archive / Florida / Mesoscale Discussions in 2018

Mesoscale Discussion 1639

November 12, 20186 counties in Alabama; 9 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Nov 12, 2018, 3:51 PM CST for 6 counties in Alabama; 9 counties in Florida. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Nov 12, 2018, 3:51 PM CST (21:51 UTC)
Expired: Nov 12, 2018, 5:45 PM CST
In force: 114 min
Issued by: the Storm Prediction Center

Counties Coffee County, AL, Covington County, AL, Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Bay County, FL, Calhoun County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL

The radar

The Eglin Afb radar (KEVX), 20 km from the middle of the area, began a volume at 21:50 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, 9.9 hours before the alert went out and 139 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: 665 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 395 m²/s²
0-3 km storm-relative helicity: 411 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
Nov 12, 4:34 AM CST	Tornado Watch	SPC	Baldwin, Mobile	7 hr
Nov 12, 7:54 AM CST	Mesoscale Discussion	SPC	Baldwin, Mobile	2 hr
Nov 12, 11:25 AM CST	Mesoscale Discussion	SPC	Baldwin, Covington, Escambia, Geneva, Mobile	95 min
Nov 12, 11:46 AM CST	Tornado Watch	SPC	Baldwin, Coffee, Covington, Dale, Escambia, Geneva and 3 more	7 hr

Nearby

Mesoscale Discussions in Florida, 2018 Mesoscale Discussions in Alabama, 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.