GOES-15 6.5 µm water vapor images + Water vapor winds (click image to play animation)

McIDAS images of GOES-15 6.5 µm water vapor channel data with overlays of hourly water vapor atmospheric motion vectors (above; click image to play animation) revealed the large cyclonic circulation of an upper-level low that was moving westward toward the Hawaiian Islands on 21 May – 22 May 2012. The warm water vapor brightness temperatures (yellow color enhancement) exhibited within the core of the low indicated that the air in the middle to upper troposphere was rather dry.

AWIPS images of the MIMIC Total Precipitable Water product (below; click image to play animation) showed that the upper-level low was not effectively tapping into the band of high moisture along the Inter-Tropical Convergence Zone (ITCZ). Since there was no surface feature associated with this upper-level low, the only significant impacts to Hawaii were strong winds at the higher elevations — a wind advisory was issued for the summits above 6000-8000 feet.

MIMIC Total Precipitable Water product (click image to play animation)

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MTSAT 0.73 µm visible channel images (click image to play animation)

An annular eclipse of the sun took place on May 21, 2012, and its shadow was visible from satellite imagery (A previous example from this blog is here). The loop above shows MTSAT imagery; the shadow of the eclipse emerges shortly after sunrise and tracks northeastward into the Pacific Ocean. The loop below shows GOES-West imagery, tracking the shadow from the north Pacific Ocean to the coast of North America around sunset.

GOES-15 0.62 µm visible channel images (click image to play animation)

A portion of the eclipse shadow could also be seen on an AWIPS image of POES AVHRR 0.86 µm visible channel data (below), extending from the far northern Pacific Ocean across the Aleutian Islands and into the southern Bering Sea.

POES AVHRR 0.86 µm visible channel image

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GOES-13 0.63 µm visible and 3.9 µm shortwave IR images (click image to play animation)

A few large wildfires flared up during the afternoon hours on 20 May 2012 across parts of far eastern Ontario and far western Quebec. In a comparison of GOES-13 0.63 µm visible channel and 3.9 µm shortwave IR channel images (above; click image to play animation; also available as a QuickTime movie), large smoke plumes could be seen emanating from the larger fires, as the fire “hot spots” (black pixels on the shortwave IR imagery) grew in size. The GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-10 minutes (compared to the routine operational 15-minute image interval).

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AVHRR 10.8 µm, MODIS 11.0 µm, and VIIRS 11.45 µm IR images

The 2012 Atlantic Basin tropical cyclone season began with the formation of Tropical Storm Alberto off the coast of South Carolina on 19 May 2012. A sequence of AWIPS images of 1-km resolution POES AVHRR 10.8 µm, Terra/Aqua MODIS 11.0 µm, and Suomi NPP VIIRS 11.45 µm IR images (above) showed the growth of deep convecion associated with Alberto as the system moved southwestward — cloud top IR brightness temperatures were as cold as -72º C on the MODIS image at 16:03 UTC.

A comparison of the 18:27 UTC 1-km resolution Suomi NPP VIIRS 11.45 µm IR image with the 18:15 UTC 4-km resolution GOES-13 10.7 µm IR image (below) demonstrated the improvement in cloud top feature identification with higher spatial resolution, as well as showed the effect of parallax due to the large satellite viewing angle from GOES-13.

GOES-13 10.7 µm IR + Suomi NPP VIIRS 11.45 µm IR image

An animation of GOES-13 0.63 µm visible channel images from the CIMSS Tropical Cyclones site (below) showed the development of a more organized cloud structure during the day. In addition, a 21 UTC ship report near the center of Alberto noted wind gusts to 65 knots, which promted NHC to issue an update to note an increase in intensity.

GOES-13 0.63 µm visible channel images + Ship reports

An AWIPS night-time image of the Suomi NPP VIIRS 0.7 µm “Day/Night Band” (below) revealed some of the cloud structure associated with Tropical Storm Alberto at 06:45 UTC (2:45 am local time). Given that there was a “New Moon” phase at this time, not a great deal of reflected light was avaiable to allow the Day/Night Band imagery to show more cloud detail.

Lights from cities and towns across the far southeastern US could also be seen in the Day/Night Band image (although some of the urban area light signatures were attenuated somewhat by overhead cloud cover).

Suomi NPP VIIRS 0.7 µm Day/Night Band image

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