Severe thunderstorms developed over northwestern Kansas on 19 June 2007. An AWIPS image of the MODIS 11.0µm InfraRed (IR) channel (above) revealed an “enhanced-v” and a “warm trench” IR signature on adjacent storm tops. The coldest cloud top brightness temperature values were -77º C on both signatures; the warmest IR temperature associated with the “enhanced-v” was -58º C, while the warmest IR temperature in the “warm trench” was –61º C. You can get a sense that such a “trench” can surround an overshooting top by examining astronaut photography of thunderstorms taken from the space shuttle (image courtesy of Earth Sciences and Image Analysis Laboratory, NASA Johnson Space Center).

A closer view of the MODIS IR image with a different color enhancement (above) shows that both IR signatures were surrounded by clusters of negative (yellow) and positive (red) cloud-to-ground (CG) lightning strikes. SPC storm reports listed hail (up to 1.75 inches in diameter) within 1 hour of the MODIS image in the region of both IR signatures, but only the southernmost enhanced-v storm produced a tornado; however, higher radar reflectivity values (65-70 dBz) were seen with the northernmost “warm trench” storm.

A comparison of the GOES-12 and MODIS IR images (above) demonstrates the better detection capability of these types of IR signatures using 1-km resolution MODIS IR imagery (vs 4-km resolution GOES IR imagery). The IR channels on the next-generation GOES-R Advanced Baseline Imager (ABI) will have a 2-km resolution.

GOES-12 10.7µm IR imagery (above; 100-image QuickTime animation) showed that these severe thunderstorms in Kansas persisted into the nighttime hours, and eventually became part of a very large Mesoscale Convective Complex (MCC) farther to the south over Oklahoma and Texas. Note the large number of IR pixels exhibiting brightness temperatures of -80º C or colder (violet enhancement) after 02:02 UTC; IR brightness temperatures were as cold as -93º C on a 23:22 UTC NOAA-12 AVHRR IR image, and as cold as -84º C on 05:10/05:13 UTC GOES / MODIS IR images (with 4159 negative and 334 positive CG lightning strikes at that time). Later SPC storm reports included hail up to 4.25 inches in diameter in Kansas (at around 00:05 UTC), and wind gusts to 94 mph in Texas (at around 07:09 UTC).

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Severe thunderstorms developed across parts of Montana on 16 June 2007, producing heavy rainfall (2-6 inches), large hail (up to 3 inches in diameter), damaging winds (gusting to 89 mph), and isolated tornadoes (SPC storm reports). GOES-11 10.7µm InfraRed (IR) imagery (above; Java animation) indicated cloud top brightness temperature values were as cold as -68º C (dark red enhancement) with these storms.

A closer view using GOES-11 visible channel imagery (above; Java animation) shows the storms in the Billings (KBIL) and Glasgow (KGGW) regions. Of particular interest was the northernmost Glasgow storm, whose northwest-to-southeast track deviated from that of the other eastward or northeastward-moving areas of convection over eastern Montana that day. Also note that the southernmost Billings storm exhibited a well-defined anvil plume after about 00:00 UTC on 17 June — this anvil plume was quite apparent in the visible imagery, but did not seem to exhibit much of a signal in the IR imagery (below).

The large hail (driven by strong winds) from the northernmost Glasgow storm produced extensive damage to the wheat, alfalfa, and corn crops in that region — Tanja Fransen (WCM, NWS Glasgow) alerted us to the fact that the northwest-to-southeast oriented hail damage swath was clearly evident on Aqua MODIS true color imagery on 20 June, 4 days following the storm (below). A Java image fader applet allows a comparison between the MODIS images on 10 June (before the storm) and 20 June (after the storm), further highlighting hail damage swath. NWS Glasgow measured the damage swath to be about 285 miles long, and up to 12 miles wide (NWS public information statement).

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A series of low-level convective outflow boundaries was seen moving off the coast of Cuba on 08 June 2007. GOES-12 visible imagery (above; Java animation) shows the narrow convex cloud bands as they propagated across the offshore waters; note how new convection was seen to develop where adjacent outflow boundaries intersected.

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An outbreak of severe thunderstorms developed across the Upper Midwest states on 07 June 2007 — SPC storm reports showed widespread tornadoes (including the EF-3 Langlade WI tornado), large hail, and damaging winds over much of the region. GOES-12 Visible (0.65 µm) images (above; click to play animation) revealed a large area of boundary layer wave clouds that developed during the morning hours over a good deal of western Wisconsin and extreme northeastern Iowa and southeastern Minnesota.

GOES-12 Infrared (10.7 µm) images (below; click to play animation) depicted cloud top brightness temperatures as cold as -69º C / -92º F (dark red enhancement) as the storms intensified during the afternoon. The dynamics associated with this severe weather outbreak were quite strong, with very fast jet stream winds at the 500 hPa and 250 hPa pressure levels. The 1-km resolution MODIS 6.7 µm water vapor imagery indicated a broad area of potential clear air turbulence downwind of the Rocky Mountains, with the characteristic “herringbone signature” extending as far eastward as western Kansas.

CIMSS employee Derrick Herndon was chasing these storms in central Wisconsin, and took a photo of some very large hail near Wisconsin Rapids (below). The largest hail listed on the SPC storm reports for that day was 4.25 inches in diameter at Wisconsin Rapids.

An interesting feature seen on MODIS false-color imagery (below) was the southwest-to-northeast oriented swaths of wet ground left in the wake of rainfall from storms moving across portions of northeastern Iowa and southeastern Minnesota. Note the cooler temperatures (60s and 70s F) at locations within the rainfall swaths. The larger rain swath was still evident on the following day, with surface temperature at Preston, Minnesota (station identifier KFKA) remaining 2-3 degrees cooler than surrounding sites.

2 days later (on 09 June), the long-track tornado damage path across northeastern Wisconsin was very evident on a Terra MODIS true-color image (below), courtesy of the Environmental Remote Sensing Center.

===== 07 June 2017 Update =====

On the 10-year anniversary of this event, a storm summary was published by NWS Green Bay. The tornado damage path was still evident on monthly Aqua MODIS true-color Red/Green/Blue (RGB) images from 06 January to 07 June 2017 (below). Previous blog posts had shown this tornado damage path on 15 July 2015 and 03 December 2007.

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