Alert archive / Alabama / Mesoscale Discussions in 2015

Mesoscale Discussion 2055

December 24, 201525 counties in Alabama; Holmes County, Florida; 15 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Dec 24, 2015, 3:10 AM CST for 25 counties in Alabama; Holmes County, Florida; 15 counties in Georgia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Dec 24, 2015, 3:10 AM CST (09:10 UTC)
Expired
Dec 24, 2015, 5:15 AM CST
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 41 counties

Autauga County, AL, Barbour County, AL, Bullock County, AL, Butler County, AL, Chambers County, AL, Coffee County, AL, Conecuh County, AL, Covington County, AL, Crenshaw County, AL, Dale County, AL, Dallas County, AL, Elmore County, AL, Escambia County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Monroe County, AL, Montgomery County, AL, Pike County, AL, Russell County, AL, Tallapoosa County, AL, Wilcox County, AL, Holmes County, FL, Calhoun County, GA, Chattahoochee County, GA, Clay County, GA, Early County, GA, Harris County, GA, Marion County, GA, Miller County, GA, Muscogee County, GA, Quitman County, GA, Randolph County, GA, Schley County, GA, Stewart County, GA, Talbot County, GA, Terrell County, GA, Webster County, GA

The radar

The Maxwell AFB radar (KMXX), 66 km from the middle of the area, began a volume at 09:13 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.

The nearest sounding before it

Birmingham, AL (KBMX), launched 00:00Z, 9.2 hours before the alert went out and 161 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-pSkew-T log-p diagram, Birmingham, AL at 00:00Z on 2015-12-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 309 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Birmingham, AL at 00:00Z on 2015-12-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 328 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
309 J/kg
Mixed-layer CIN
-104 J/kg
Mixed-layer LCL
738 m above ground
0-6 km bulk shear
67 kt
0-1 km storm-relative helicity
328 m²/s²
0-3 km storm-relative helicity
466 m²/s²
Significant tornado parameter
0.0
Supercell composite
6.6

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.

IssuedProductOfficeCountiesLasted
Dec 23, 6:35 PM CSTMesoscale DiscussionSPCColbert, Franklin, Lauderdale, Lawrence, Limestone, Madison and 1 more55 min
Dec 23, 7:41 PM CSTMesoscale DiscussionSPCBibb, Fayette, Greene, Hale, Jefferson, Lamar and 8 more2 hr
Dec 23, 8:20 PM CSTTornado WatchSPCBibb, Fayette, Greene, Hale, Jefferson, Lamar and 7 more8 hr
Dec 23, 10:11 PM CSTMesoscale DiscussionSPCBlount, Calhoun, Cherokee, Cullman, DeKalb, Etowah and 12 more2 hr
Dec 23, 10:33 PM CSTTornado WatchSPCCullman, DeKalb, Jackson, Lawrence, Limestone, Madison and 2 more5 hr
Dec 24, 3:27 AM CSTMesoscale DiscussionSPCBibb, Blount, Calhoun, Chambers, Cherokee, Chilton and 16 more93 min
Dec 24, 4:09 AM CSTTornado WatchSPCBarbour, Bullock, Coffee, Dale, Geneva, Henry and 5 more7 hr
Dec 24, 7:07 AM CSTMesoscale DiscussionSPCBarbour, Bullock, Coffee, Covington, Dale, Henry and 2 more83 min

Nearby

Mesoscale Discussions in Alabama, 2015Mesoscale Discussions in Georgia, 2015Mesoscale Discussions in Florida, 2015Every 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.