Alert archive / Georgia / Mesoscale Discussions in 2008

Mesoscale Discussion 2449

December 11, 2008Orange County, Seminole County, Volusia County, Florida; 5 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Dec 11, 2008, 11:21 AM EST for Orange County, Seminole County, Volusia County, Florida; 5 counties in Georgia. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued: Dec 11, 2008, 11:21 AM EST (16:21 UTC)
Expired: Dec 11, 2008, 12:15 PM EST
In force: 54 min
Issued by: the Storm Prediction Center

Counties Orange County, FL, Seminole County, FL, Volusia County, FL, Bryan County, GA, Bulloch County, GA, Glynn County, GA, Liberty County, GA, McIntosh County, GA

The radar

The Jacksonville radar (KJAX), 84 km from the middle of the area, began a volume at 16:20 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

Jacksonville, FL (KJAX), launched 12:00Z, 4.4 hours before the alert went out and 86 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: 286 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 567 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 205 m²/s²
0-3 km storm-relative helicity: 241 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.8

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
Dec 11, 5:27 AM EST	Mesoscale Discussion	SPC	Alachua, Baker, Bradford, Citrus, Clay, Columbia and 29 more	33 min
Dec 11, 5:48 AM EST	Tornado Watch	SPC	Alachua, Baker, Bradford, Citrus, Clay, Columbia and 31 more	6 hr
Dec 11, 8:24 AM EST	Mesoscale Discussion	SPC	Alachua, Baker, Bradford, Brevard, Citrus, Clay and 20 more	66 min
Dec 11, 10:01 AM EST	Mesoscale Discussion	SPC	Banks, Burke, Clarke, Columbia, Elbert, Franklin and 16 more	119 min
Dec 11, 10:15 AM EST	Severe Thunderstorm Watch	SPC	Banks, Barrow, Burke, Clarke, Columbia, Elbert and 18 more	4 hr

Nearby

Mesoscale Discussions in Georgia, 2008 Mesoscale Discussions in Florida, 2008 Every mesoscale discussion in 2008

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.