Alert archive / Alabama / Mesoscale Discussions in 2015

Mesoscale Discussion 1912

October 31, 201515 counties in Alabama; 5 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Oct 31, 2015, 4:35 PM CDT for 15 counties in Alabama; 5 counties in Florida. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: Oct 31, 2015, 4:35 PM CDT (21:35 UTC)
Expired: Oct 31, 2015, 6:30 PM CDT
In force: 115 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Baldwin County, AL, Butler County, AL, Clarke County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Escambia County, AL, Geneva County, AL, Lowndes County, AL, Mobile County, AL, Monroe County, AL, Pike County, AL, Washington County, AL, Wilcox County, AL, Escambia County, FL, Holmes County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL

The radar

The Mobile radar (KMOB), 112 km from the middle of the area, began a volume at 21:38 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 529Oct 31, 5:00 PM CDT

The nearest sounding before it

Birmingham, AL (KBMX), launched 12:00Z, 9.6 hours before the alert went out and 226 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: 1903 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 205 m²/s²
0-3 km storm-relative helicity: 332 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 31, 4:57 PM CDT	Tornado Watch	SPC	Baldwin, Choctaw, Clarke, Conecuh, Escambia, Mobile and 3 more	4 hr

Nearby

Mesoscale Discussions in Alabama, 2015 Mesoscale Discussions in Florida, 2015 Every mesoscale discussion in 2015

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.