POES AVHRR 12.0 µm IR channel and 0.86 µm visible channel (with surface data)

Tropical Storm Karen formed in the far southern Gulf of Mexico early in the day on 03 October 2013. About 2 hours after formation, AWIPS images of 1-km resolution POES AVHRR 12.0 µm IR channel and 0.86 µm visible channel data at 15:44 UTC (above) showed that areas of organized deep convection were displaced well to the east and north of the center of Karen.

A few hours later at 18:17 UTC, 375-meter resolution (projected onto a 1-km AWIPS grid) Suomi NPP VIIRS 11.45 µm IR data (below) revealed that a small convective burst had formed just to the northwest of the low-level circulation center (LLCC).

Suomi NPP VIIRS 11.45 µm IR channel and 0.64 µm visible channel images (with surface data)

McIDAS images of 1-km resolution 0.63 µm GOES-13 visible channel data (below; click image to play animation) showed the exposed LLCC as it migrated slowly northwestward. Additional convective bursts near the LLCC werer seen to develop at the end of the animation. Another feature of interest was the well-defined low-level arcing convective outflow boundary moving northward away from the convective activity that was dissipating along the northern fringe of the Karen. Note that the GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-10 minutes.

GOES-13 0.63 µm visible channel images (click image to play animation)

From the CIMSS Tropical Cyclones site, an animation of 4-km resolution GOES-13 10.7 µm IR channel imagery with an ovelay of the deep-layer wind shear (below) depicted about 20 knots of wind shear, which was acting to keep the most of the main convection away from the exposed LLCC.

GOES-13 10.7 µm IR channel images with Deep layer wind shear

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Suomi NPP VIIRS 0.7 µm Day/Night Band image

An AWIPS image of Suomi NPP VIIRS 0.7 µm Day/Night Band data (above) revealed a bright band of the aurora borealis that stretched from northern North Dakota and Minnesota into Quebec at 07:12 UTC (2:12 AM Central time) on 02 October 2013. This aurora display was caused by a coronal mass ejection from the Sun on 30 September.

The aurora borealis was faintly visible on a YouTube video (below; courtesy of Pete Pokrandt, UW-AOS) created using 10-second black and white images from the north-facing UW-SSEC/AOS rooftop camera.

YouTube video of UW-SSEC/AOS rooftop camera images

A higher-quality digital camera photo taken from the roof of the UW-SSEC/AOS building (below) showed some of the green color of the aurora display (in spite of the high level of urban light pollution from the Madison area). Brighter green colors were seen on images taken further away from Madison, in Verona and Dodgeville in southern Wisconsin.

Photo from top of UW-SSEC/AOS building (courtesy of John Lalande, SSEC)

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Suomi NPP VIIRS 0.7 µm Day/Night Band image

An AWIPS image of Suomi NPP VIIRS 0.7 µm Day/Night Band (DNB) data at 06:10 UTC or 2:10 AM local time on 30 September 2013 (above) revealed multiple signatures of mesospheric airglow waves over portions of the western Atlantic Ocean. There are three distinct packets of waves seen on the DNB image — two of which were likely generated by intense mesoscale convective systems associated with a strong occluding mid-latitude cyclone centered several hundred miles north-northwest of Bermuda. The impressive length of the third (southernmost) wave packet located southeast of Bermuda can better be seen in the full DNB swath image (courtesy of Kathy Strabala, SSEC); this feature is likely a high-altitude undular bore.

A comparison of the VIIRS DNB image (and cloud-to-ground lightning strike data) with the corresponding VIIRS 11.45 µm IR image (below) showed that there was no signature of these mesospheric airglow waves on the IR image.

Suomi NPP VIIRS 11.45 µm IR channel and 0.7 µm Day/Night Band images, with cloud-to-ground lightning strikes

A magnified comparison of VIIRS DNB and IR images (below) showed the difference between the short wavelength of cloud-top gravity waves propagating southwestward away from an overshooting top (located between the two lightning streaks) and the longer-wavelength mesospheric airglow waves seen along and south of the southernmost lightning streak. The DNB image lightning streaks are an artifact of sensor saturation by very bright cloud-top illumination resulting from intense lightning activity.

Suomi NPP VIIRS 11.45 µm IR and 0.7 µm Day/Night Band images

Other examples of mesospheric airglow waves were seen on 15 September 2013 and 05 April 2013.

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GOES-13 0.63 µm visible channel images (click image to play animation)

McIDAS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) showed a large area of fog and stratus that persisted for the entire day over the northwestern portion of Lake Superior on 25 September 2013. Morning fog over adjacent parts of Ontario, Michigan, Wisconsin, and Minnesota quickly dissipated as daytime heating and boundary layer mixing increased, but the fog and stratus cloud mass remained over the relatively cool waters of Lake Superior; MODIS Sea Surface Temperature values from the previous day (below) were generally in the lower to middle 50s F (green to yellow color enhancement) over that portion of the lake.

Additional details of the fog/stratus features can be seen in AWIPS images of 375-meter resolution (projected onto a 1-km AWIPS grid) Suomi NPP VIIRS 0.64 µm visible channel data at 19:06 UTC, along with a 250-meter resolution Aqua MODIS true-color Red/Green/Blue (RGB) image at 19:43 UTC (below).

Suomi NPP VIIRS 0.64 µm visible channel image, with MODIS true-color image (upper left corner)

A closer look at the 250-meter resolution Aqua MODIS true-color RGB image from the SSEC MODIS Today site (below) revealed two additional features of interest: (1) a signature of the burn scar that remained from the Pagami Creek Fire that occurred in September 2011, and (2) the first indications of Autumn tree colors over parts of far northern Wisconsin and the western Upper Peninsula of Michigan.

Aqua MODIS true-color image

Note that Isle Royale could be seen protruding through the fog/stratus features during much of the day; with the maximum elevation of the island being 1394 feet, this indicates that the fog/stratus depth was less than that value. The GOES-R Cloud Thickness algorithm (applied to GOES-13 data) shortly after sunset depicted values that were generally 1200 feet (cyan color enhancement) or less (below).

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