Suomi NPP VIIRS 0.64 um visible image and 11.45 um IR channel image (with overlay of METAR surface reports)

A tornado touched down just east of the Denver International Airport concourses at 20:21 UTC on 18 June 2013, producing a peak wind gust of 97 mph (before the wind instrumentation stopped transmitting data).  AWIPS images of Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel data at 20:03 UTC (above) showed the storm about 20 minutes before it produced the tornado. The minimum cloud-top IR brightness temperature was -68º C (darker red color enhancement), which was significantly colder that the tropopause temperature of -56º C on the 12 UTC Denver rawinsonde data.

The corresponding Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image (viewed using the SSEC Web Map Server) is shown below.

Suomi NPP VIIRS true-color Red/Green/Blue (RGB) image

The series of METAR surface reports from Denver (KDEN) during the period from 20:20 to 20:37 UTC:

KDEN 182037Z 09026KT 9SM -TSRA FEW050 BKN080CB BKN180 24/04 A3002 RMK FUNNEL CLOUD B18 FUNNEL CLOUD E20 TORNADO B21 TORNADO E36 AO2 LTG DSNT NE-S RAB03 TORNADO 2 SE MOV N P0005
KDEN 182032Z 09026KT 7SM +FC -TSRA FEW050 BKN080CB BKN180 22/08 A3001 RMK FUNNEL CLOUD B18 FUNNEL CLOUD E20 TORNADO B21 AO2 LTG DSNT NE-S RAB03 TORNADO 2 SE MOV N P0005
KDEN 182022Z 06021G28KT 5SM +FC TSRA FEW050 BKN080CB BKN180 21/07 A3002 RMK FUNNEL CLOUD B18 FUNNEL CLOUD E20 TORNADO B21 AO2 PK WND 07028/2020 LTG DSNT E-S RAB03 OCNL LTGICCG VC E TS OHD MOV E VIRGA SW P0005
KDEN 182021Z 06022G28KT 5SM +FC TSRA FEW050 BKN080CB BKN180 21/06 A3003 RMK FUNNEL CLOUD B18 FUNNEL CLOUD E20 TORNADO B21 AO2 PK WND 07028/2020 LTG DSNT E-S RAB03 OCNL LTGICCG VC E TS OHD MOV E VIRGA SW P0005
KDEN 182020Z 07020G28KT 5SM FC +TSRA FEW050 BKN080CB BKN180 21/07 A3003 RMK FUNNEL CLOUD B18 AO2 PK WND 07028/2020 LTG DSNT E-S RAB03 OCNL LTGICCG VC E TS OHD MOV E VIRGA SW P000

McIDAS images of GOES-13 0.63 µm visible channel data (below; click image to play animation) showed the development of the thunderstorms over the region

GOES-15 0.63 µm visible channel images (click image to play animation)

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GOES-15 0.63 µm visible channel images (click image to play animation)

McIDAS images of GOES-15 0.63 µm visible channel data (above; click image to play animation) revealed an uncharacteristically cloud-free view of most of the interior of Alaska on 17 June 2013. A large blocking ridge of high pressure had been building across the region, which helped to set the stage for record high temperatures at a number of locations — on 16 June many sites reported daily maximum temperatures in the middle to upper 80s F, with a few sites hitting the 90º F mark (regional temperatures and precipitation). In south-central Alaska, several locations set all-time record highs on 17 June.

On the previous day, a comparison of AWIPS images of Suomi NPP VIIRS 0.64 µm visible channel and 3.74 µm shortwave IR data (below) showed that the Alaska fire season was well underway, with a number of fire “hot spots” (black to yellow to red color enhancement) appearing on the shortwave IR image; some of these larger fires were producing smoke plumes that could be seen on the visible image. Again, note the unusually warm tempertures at many of the reporting sites. Smoke plumes from a couple of the larger fires could also be seen in southwestern and southeastern Alaska on the animation of GOES-15 visible images above. Closer views of pyrocumulonimbus clouds associated with the largest fires can be seen here.

Suomi NPP VIIRS 0.64 µm visible channel and 3.74 µm shortwave IR channel images

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GOES-13 visible channel and 3.9 µm shortwave IR images (click image to play animation)

GOES-13 (GOES-East) 0.63 µm visible channel and 3.9 µm shortwave IR channel images (above; click image to play animation) showed signals of a brief eruption (video 1 | video 2) of the Popocatépetl volcano in Mexico on 17 June 2013. A volcanic ash plume can be seen drifting southwestward on the visible images, and a warm thermal anomaly (black to red color enhancement) appear on the shortwave IR images. According to an advisory issued by the Washington Volcanic Ash Advisory Center, the maximum height of the ash was expected to be around 28,000 feet.

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GOES-14 0.63 µm visible channel images (click image to play animation)

For the second consecutive day, the GOES-14 satellite was placed into Super Rapid Scan Operations for GOES-R (SRSOR) mode to monitor the ongoing severe bow echo/low-end derecho event that was moving across the eastern US on 13 June 2013. GOES-14 0.63 µm visible channel images at 1-minute intervals (above; click image to play animation; also available as a QuickTime movie) revealed the emergence of a well-defined shelf cloud across Virginia and North Carolina, which marked the leading edge of the gust front moving out ahead of the line of severe thunderstorms. According to the SPC storm reports, these storms produced a wide swath of damaging winds (with gusts as high as 78 mph in Virginia), along with some large hail (up to 2.75 inches in diameter in Maryland).

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