Suomi NPP VIIRS 11.45 µm IR image with surface analysis

The National Weather Service forecast office at Juneau, Alaska mentioned their use of Suomi NPP VIIRS imagery:

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
553 AM AKST WED NOV 21 2012

.SHORT TERM…SOMEWHAT COMPLICATED PATTERN IN THE GULF AND NORTHEAST PACIFIC THIS MORNING. THERE ARE AROUND 4 SEPARATE
CIRCULATION CENTERS VISIBLE ON IR AND VIIRS NIGHTTIME VISIBLE IMAGES. THE STRONGEST IS WEST OF DIXON ENTRANCE CURRENTLY AND IS SLOWLY WEAKENING AS IT REMAINS NEARLY STATIONARY. A SECOND LOW IS JUST SE OF KODIAK ISLAND, A THIRD IS AROUND 50N 140W, AND THE FOURTH IS A VERY WEAK ONE OVER HAIDA GWAII.

AWIPS images of Suomi NPP VIIRS 11.45 µm IR channel (above) and 0.7 µm Day/Night Band data (below) at 12:14 UTC or 3:14 AM local time on 21 November 2012 showed the cloud features associated with the complex pattern over the Gulf of Alaska at that particular time (comparison of IR and Day/Night Band images).

Items of interest to note on the VIIRS IR image: (1) wave clouds well downwind (to the south of) the Aleutian Islands, where northerly winds were as strong as gale force, and (2) large patches of fog and stratus clouds (VIIRS IR brightness temperature difference “Fog/stratus product”) across parts of the Yukon, east-central Alaska, and the North Slope region of Alaska.

Interesting features to point out on the Day/Night Band image include: (1) the bright city lights of populated areas such as Anchorage and Fairbanks, (2) bright northwest-to-southeast oriented swaths of the Aurora Borealis across parts of Alaska and the Yukon, as well as just off the Arctic Ocean coastline, and (3) the cluster of bright lights associated with drilling activity in the Prudhoe Bay oil field area along the northern coast of Alaska.

Suomi NPP VIIRS 0.7 µm Day/Night Band image with surface analysis

A comparison of GOES-15 10.7 µm IR and Suomi NPP VIIRS 11.45 µm IR images (below) shows that in far northern latitudes the superior spatial resolution of imagery from polar-orbiter satellites provides much clearer view of many of the the various cloud features.

Suomi NPP VIIRS 11.45 µm IR and GOES-15 10.7 µm IR images

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MTSAT-1R 0.7 µm visible channel images

The shadow from a total solar eclipse could be seen moving east-southeastward across northeastern Australia and the adjacent waters of the South Pacific Ocean on Japanese MTSAT-1R 0.7 µm visible channel images (above).

The solar eclipse shadow was also evident on a visible image from the Korean COMS-1 satellite (below).

COMS-1 visible channel image

As the eclipse shadow continued to move eastward, it was seen on a US NOAA GOES-15 0.63 µm visible channel image (below).

GOES-15 0.63 µm visible channel image

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GOES-15 (left) and GOES-13 (right) 0.63 µm visible images (click image to play animation

Cold air flowing southeastward across the Great Salt Lake in Utah had enough of a fetch over the warm waters to help set up a well-defined lake-effect snow (LES) band that produced several inches of snowfall downwind of the lake at Salt Lake City on 11 November 2012. The LES band could be seen in McIDAS images of GOES-15 (GOES-West) and GOES-13 (GOES-East) 0.63 µm visible channel data (above; click image to play animation).

AWIPS images of POES AVHRR 0.63 µm visible channel and 10.8 µm IR channel data (below) showed that IR cloud top brightness temperatures within the LES band were as cold as -27º C (darker blue color enhancement).

POES AVHRR 0.63 µm visible channel and 10.8 µm IR channel images

On the previous day, the MODIS Sea Surface Temperature (SST) product (below) indicated that mid-lake SST values were as warm as 51.5º F (light green color enhancement) — so the cold air flowing over the warm waters created a very unstable lower-tropospheric thermal profile that aided the development of the lake-effect snow band. For more discussion on this particular case, see a write-up on The Weather Channel site.

MODIS Sea Surface Temperature product

Meanwhile, farther to the east in South Dakota, cold arctic air was flowing southeastward across the still-unfrozen waters of the Missouri River (whose flow is controlled by several dams that create large reservoirs such as Lake Oahe and Lake Sharpe). Even though the fetch of the cold air across the water was relatively small, there were still a number of “lake-effect” or “river-effect” cloud bands seen on GOES-13 0.63 µm visible channel images (below; click image to play animation) — in particular, a long and well-defined cloud band extending downwind of the large horseshoe-shaped oxbow bend in Lake Sharpe. Such lake-effect clouds were also described in 2009 and 2008 on this blog.

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

A comparison of AWIPS images of MODIS 0.65 µm visible channel and a false-color Red/Green/Blue (RGB) composite (below) demonstrated the value of using RGB imagery to help discriminate between snow cover (enhanced in darker shades of red) and supercooled water droplet clouds (which appear as varying shades of white).

MODIS 0.64 µm visible channel and false-color Red/Green/Blue (RGB) images

A closer view using 250-meter resolution MODIS true-color and false-color RGB images from the SSEC MODIS Today site (below) showed even greater detail in the structure of these cloud bands downwind of the Missouri River in South Dakota. In this RGB image, snow cover appeared as shades of cyan.

MODIS true-color and false-color Red/Green/Blue (RGB) images

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MODIS 11-12 µm IR brightnes temperature difference with surface METAR reports and frontal analysis

Strong southwesterly winds (gusting as high as 86 mph in New Mexico and 73 mph in Texas) ahead of an advancing cold front were causing dense plumes of blowing dust that restricted surface visibility to 0.5 mile at El Paso, Texas (station identifier KELP) on 10 November 2012. An AWIPS image of the 1-km resolution MODIS 11-12 µm IR brightness temperature difference (BTD) product (above) showed the areal coverage of the blowing dust (cyan to yellow color enhancement) at 20:17 UTC (3:17 PM local time).

The blowing dust plumes could also be seen on a 250-meter resolution MODIS true-color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (below).

MODIS true-color Red/Green/Blue (RGB) image (displayed using Google Earth)

MODIS 0.65 µm visible channel and 11.0 µm IR channel images

AWIPS comparisons of 1-km resolution MODIS (above) and Suomi NPP VIIRS (below) visible channel and IR channel images revealed that the airborne dust exhibited a cooler signature (lighter gray enhancement) on the IR imagery.

Suomi NPP VIIRS 0.64 µm visible channel and 11.45 µm IR channel images

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