A mid-latitude cyclone intensified as it moved northeastward across Nebraska, the eastern Dakotas and northern Minnesota (3-hourly surface analyses) during 25 December – 26 December 2016. GOES-13 (GOES-East) Water Vapor (6.5 µm) images (above) showed distinct banding within the warm conveyor belt, a well-defined dry slot, and a large comma head that formed from the cold conveyor belt. The storm produced blizzard conditions across much of the Northern Plains and Upper Midwest, with heavy snowfall (as much as 22.0 inches in western North Dakota), freezing rain (ice accretion as thick as 0.5 inch in Minnesota and North Dakota) , sleet (up to 2.0 inches deep in Minnesota) and heavy rainfall; in Kansas there were also a few tornadoes (SPC storm reports).

A noteworthy characteristic of the storm was very strong winds — a closer view of GOES-13 Water Vapor imagery with hourly plots of surface wind gusts (in knots) is shown below.

Note the swath of wind gusts in the 50-60 knot range which progressed across central and northeastern Nebraska into northwestern Iowa and finally southwestern Minnesota during the 02 UTC to 12 UTC period on 26 December — this was pointed out in a tweet by Anthony Sagliani as a “sting jet” feature:

Beautiful example of a bent-back occlusion/sting jet tonight in the Northern Plains, complete with a "false" warm sector. pic.twitter.com/36ChcoGFqS

— Anthony Sagliani (@anthonywx) December 26, 2016

As observed in previous sting jet cases (03 Jan 2012 | 28 Oct 2013), the strongest winds occurred near the curved “scorpion tail” signature seen in the water vapor imagery (which marked the leading edge of the cold conveyor belt as it advanced into the rear edge of the dry slot of the cyclone circulation).

A comparison of Aqua MODIS Visible (0.65 µm), Infrared Window (11.0 µm) and Water Vapor (6.7 µm) images at 2001 UTC on 25 December is shown below.

A closer view with Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1952 UTC on 25 December (below) showed a detailed view of the banded cloud structures from Kansas into South Dakota, as well as small overshooting tops associated with thunderstorms in southeastern South Dakota and southwestern Minnesota. This storm produced the first Christmas Day thunderstorms on record in both Sioux Falls and Rapid City, South Dakota; thundersnow was also observed in Bismarck, North Dakota.

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Rapid-scan (2.5-minute interval) 2-km resolution Himawari-8 Infrared Window (11.45 µm) images (above; also available as a 173 Mbyte animated GIF) showed Category 4 Super Typhoon Nock-Ten making landfall in the Philippines on 25 December 2016. Nock-Ten became the strongest typhoon on record (SATCON | ADT | source) in the Philippines so late in the year:

Supertyphoon #Nockten is the strongest typhoon on record (since 1945) to make landfall in the #Philippines this late in the calendar year. pic.twitter.com/jUzIUOg8hk

— Philip Klotzbach (@philklotzbach) December 25, 2016

A 375-meter resolution Suomi NPP VIIRS Infrared Window (11.45 µm) image at 1724 UTC on 24 December (below; courtesy of William Straka, SSEC) was acquired just before the beginning of the Himawari-8 animations above; note the presence of cloud-top gravity waves propagating southeastward away from the eye of Nock-Ten, in addition to prominent larger-scale transverse banding farther out within the eastern semicircle of the storm.

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Following a short-lived eruption on 21 December, the Bogoslof volcano in the eastern Aleutian Island chain of Alaska erupted again at about 0110 UTC on 22 December 2016. The volcanic cloud could be seen moving north/northeastward away from Bogoslof (denoted by the yellow * symbol) on Himawari-8 and GOES-15 Visible images (above). The higher spatial and temporal resolution from Himawari-8 (0.5 km at nadir, with images every 10 minutes) provided a more detailed view of the cloud feature compared to GOES-15 (with 1.0 km resolution at nadir, and images every 15 minutes); however, the ABI instrument on the GOES-R series will have an identical 0.5 km resolution Visible band. Another Himawari-8 Visible image animation is available from RAMMB.

Multispectral Red/Green/Blue (RGB) images from the NOAA/CIMSS Volcanic Cloud Monitoring site (below) displayed a signal of the volcanic cloud during the ~2.5 hours following the onset of the eruption — since this particular RGB combination uses the 3.9 µm Shortwave Infrared band, the volcanic cloud feature appeared as darker shades of magenta during the first few images while reflected solar illumination was present before sunset.

Another variant of RGB images (below) uses the 8.5 µm “cloud top phase” band, which is also sensitive to SO2 absorption; in this case, the appearance of the volcanic cloud feature was dominated by shades of yellow, indicating high levels of SO2.

A comparison of the 3 Himawari-8 water vapor bands (below) showed that a strong signature of the volcanic cloud was seen on the lower-tropospheric 7.3 µm band; this was due to the fact that the 7.3 µm band is also sensitive to elevated levels of SO2 loading in the atmosphere (which was also noted at the bottom of this Mount Pavlof eruption blog post). These same 3 water vapor bands (Upper-level, Mid-level and Lower-level) will be available from the GOES-R series ABI instrument.

A closer view using Himawari-8 false-color images (below) includes a magenta polygon surrounding the volcanic cloud soon after the onset of the eruption — this is an example of an experimental automated volcanic eruption alerting system. According to Michael Pavolonis (NOAA/NESDIS), “Using our automated cloud object tracking algorithm, the eruption produced a cloud at 01:30 UTC that was about 19 deg C colder than the background imaged by Himawari-8 at 01:20 UTC.  Taking into account the pixel size, background cloud cover, and time interval between successive images, the 19 deg C change is about an 11 standard deviation outlier relative to a very large database of meteorological clouds.  The vertical growth anomaly calculation is the basis of one the components of our experimental automated volcanic eruption alerting system”.

The creation of RGB images such as those shown above will be possible from the GOES-R series of satellites (beginning with GOES-16), since the ABI instrument has the 8.4 µm and 12.3 µm bands that are not available from the current generation of GOES imager instruments.

Additional satellite images of this event are available from NWS Anchorage.

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The 2016 Northern Hemisphere winter / Southern Hemisphere summer solstice occurred at 1044 UTC on 21 December. EUMETSAT Meteosat-10 Visible (0.635 µm) images (above; source) showed the westward progression of the solar terminator (which separates daylight from darkness) at 3-hour intervals.

Nearly the entire continent of Antarctica was illuminated by 24 hours of daylight, as seen on JMA Himawari-8 Visible (0.64 µm) images (below; also available as a 60 Mbyte animated GIF). Full-disk images are routinely available at 10-minute intervals from Himawari-8 (and can be available as frequently as every 5 minutes from the GOES-R series).

With the continuous daylight, Antarctic surface air temperatures from AMRC Automated Weather Stations (below; source) were seen to warm above 40ºF along the coast, and above -30ºF in the interior.

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