Alert archive / Georgia / Mesoscale Discussions in 2012

Mesoscale Discussion 2169

December 17, 2012Houston County, Alabama; 8 counties in Florida; 37 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Dec 17, 2012, 10:49 AM CST for Houston County, Alabama; 8 counties in Florida; 37 counties in Georgia. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued
Dec 17, 2012, 10:49 AM CST (16:49 UTC)
Expired
Dec 17, 2012, 12:45 PM CST
In force
116 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 46 counties

Houston County, AL, Bay County, FL, Calhoun County, FL, Gadsden County, FL, Jackson County, FL, Jefferson County, FL, Leon County, FL, Liberty County, FL, Washington County, FL, Appling County, GA, Atkinson County, GA, Bacon County, GA, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Brooks County, GA, Bulloch County, GA, Calhoun County, GA, Candler County, GA, Coffee County, GA, Colquitt County, GA, Cook County, GA, Crisp County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Effingham County, GA, Evans County, GA, Grady County, GA, Irwin County, GA, Jeff Davis County, GA, Lanier County, GA, Lowndes County, GA, Miller County, GA, Mitchell County, GA, Montgomery County, GA, Seminole County, GA, Tattnall County, GA, Telfair County, GA, Thomas County, GA, Tift County, GA, Toombs County, GA, Turner County, GA, Wheeler County, GA, Wilcox County, GA, Worth County, GA

The watches that followed

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

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 4.8 hours before the alert went out and 105 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, Tallahassee Rgnl, FL at 12:00Z on 2012-12-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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, Tallahassee Rgnl, FL at 12:00Z on 2012-12-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 186 square meters per square second.1939587897117Sfc1 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
4 J/kg
Mixed-layer CIN
-279 J/kg
Mixed-layer LCL
587 m above ground
0-6 km bulk shear
77 kt
0-1 km storm-relative helicity
186 m²/s²
0-3 km storm-relative helicity
390 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.

IssuedProductOfficeCountiesLasted
Dec 17, 4:16 AM CSTMesoscale DiscussionSPCBaldwin, Escambia, Mobile119 min
Dec 17, 1:24 PM CSTMesoscale DiscussionSPCLauderdale2 hr
Dec 17, 12:30 PM CSTTornado WatchSPCBaker, Columbia, Franklin, Gadsden, Gulf, Hamilton and 8 more5 hr
Dec 17, 1:28 PM CSTMesoscale DiscussionSPCEffingham, Screven92 min

Nearby

Mesoscale Discussions in Georgia, 2012Mesoscale Discussions in Florida, 2012Mesoscale Discussions in Alabama, 2012Every mesoscale discussion in 2012

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.