Super Tuesday 2008 Tornado Outbreak

February 6th, 2008 |

GOES-12 10.7µm IR images (Animated GIF)

The Super Tuesday 2008 Tornado Outbreak has been one of the deadliest tornado outbreaks in the US — with 59 fatalities reported so far, it ranks in the top 15 deadly tornado outbreaks (and the highest number of tornado deaths since 1985). According to the SPC Storm Reports, there were over 300 reports of tornadoes, large hail (up to 4.25 inches in diameter in Texas, Arkansas, and Missouri), and damaging wind gusts from Texas to Ohio and West Virginia. The outbreak produced at least 64 tornadoes, some producing EF-3 and EF-4 damage.

AWIPS images of the GOES-12 10.7µm IR channel (above) and the GOES-12 6.5µm “water vapor channel” (below) show the development of widespread severe convection along and ahead of an advancing cold frontal boundary during the 05 February06 February 2008 period.

GOES-12 6.5µm water vapor images (Animated GIF)

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GOES-12 sounder total precipitalbe water (Animated GIF)

Hourly images of the GOES sounder total precipitable water (above) showed that moisture was increasing ahead of the cold front, with PW values of 30-40 mm (1.2-1.6 inches) ahead of the front; the air mass ahead of the cold front was also marginally unstable, with GOES sounder CAPE values (below) of 1000-2000 J/kg.

GOES-12 sounder CAPE (Animated GIF)

AWIPS images of the 1-km resolution MODIS 11.0µm IR channel (below) show closer views of the severe convection around 03:39 UTC and 07:50 UTC — tornadoes and large hail were being reported in parts of Tennessee around those 2 times. As is often the case with winter season severe convection, no classic “enhanced-V” signatures were evident on the IR imagery.

MODIS 11.0µm IR image

MODIS 11.0µm IR image

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GOES-12 6.5µm water vapor images (Animated GIF)

Farther to the north, in the cold air, parts of southern Wisconsin received as much as 21 inches of snowfall, accompanied by strong winds that created near-blizzard conditions with significant blowing and drifting snow. The 13.3 inches that fell in Madison was the city’s second largest 24-hour snowfall amount on record, and about 800 vehicles became stranded on Interstate 90 between Madison and Janesville in southern Wisconsin. GOES-12 6.5µm water vapor channel images (above) revealed several important signatures during the long-duration winter storm event: a dry slot (which helped to release convective instability along the Illinois/Wisconsin border region), a well-defined deformation zone that set up across Iowa/Wisconsin, and a Trough of Warm Air Aloft (TROWAL) that developed westward from southern Michigan into Wisconsin/Illinois. A vertical cross section of equivalent potential temperature (GEMPAK wizardry courtesy of J. Gerth, CIMSS) oriented north-to-south from Iron Mountain, Wisconsin (IMT) to Paducah, Kentucky (PAH) (below) showed the TROWAL structure very well.

Cross Section of theta-e