Super Tuesday 2008 Tornado Outbreak

February 6th, 2008 |
GOES-12 10.7 µm IR images (Animated GIF)

GOES-12 10.7 µm IR images

The Super Tuesday 2008 Tornado Outbreak has been one of the deadliest tornado outbreaks on record 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 a total of 87 tornadoes, some producing EF-3 and EF-4 damage.

AWIPS images of GOES-12 10.7 µm IR channel (above) and GOES-12 6.5 µm “water vapor channel” data (below) showed 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)

GOES-12 6.5 µm water vapor images

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GOES-12 sounder total precipitalbe water (Animated GIF)

GOES-12 sounder Total Precipitalbe Water

Hourly images of GOES sounder Total Precipitable Water (above) showed that moisture was increasing ahead of the cold front, with TPW 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)

GOES-12 sounder CAPE

AWIPS images of 1-km resolution MODIS 11.0 µm IR channel data (below) showed 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 11.0 µm IR image

MODIS 11.0 µm IR image

MODIS 11.0 µm IR image

MODIS 11.0 µm IR image

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

GOES-12 6.5 µm water vapor images

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 2000 vehicles became stranded on Interstate 90 in southern Wisconsin (between Madison and Janesville). GOES-12 6.5 µm 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) showed the TROWAL structure very well (below).

Cross Section of theta-e

Cross Section of theta-e

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