Suomi NPP VIIRS 11.45 µm IR image (with METAR surface reports)

The coldest temperature in the United States (including Alaska) was -33 F (-36 C) at Alamosa, Colorado on 03 January 2013. AWIPS images of 375-meter resolution (projected onto a 1-km AWIPS grid) Suomi NPP VIIRS 11.45 µm IR data with METAR surface reports (above) showed a few areas in parts of the higher elevations of central Colorado which exhibited IR brightness temperatures as cold as -44 C or -47 F (white color enhancement). In the lower left portion of the image, the warmer signature (red color enhancement) of the Colorado River basin could be seen running southwestward across Utah and into the Grand Canyon region of Arizona.

Alamosa (station identifier KALS) is located in south-central Colorado, and is situated in the eastern portion of the broad high-altitude basin of the San Luis Valley. The Suomi NPP VIIRS 0.7 µm Day/Night Band image (below) showed the brighter white signature of the moonlit snow-covered San Luis Valley at night (08:49 UTC = 1:49 AM local time). Much of the western (high-elevation) half of Colorado had substantial snow cover, and there were a few other sites that recorded minimum temperatures of -30 F or colder.

Suomi NPP VIIRS 0.7 µm Day/Night Band image (with METAR surface reports)

A comparison of the Suomi NPP VIIRS IR brightness temperature difference “fog/stratus product” and the corresponding GOES-13 Cloud Thickness and IFR Probability products (below) indicated that most of the higher elevations of central Colorado were generally cloud-free, which allowed for strong radiational cooling to reach such cold surface temperatures.

Suomi NPP VIIRS “fog/stratus product” + GOES-13 Cloud Thickness and IFR Probability products

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Suomi NPP VIIRS 0.7 µm Day/Night Band image

The Suomi/NPP Day/Night Band “nightime visible” image early on 2 January captured a rope cloud extending over the central Gulf of Mexico southwestward from the northwest Florida panhandle. Rope Clouds are handy features because they accurately place the location of the cold front at the leading edge of the rope structure. METARS overlain above the Suomi/NPP image (below) over the north-central Gulf Coast demonstrate how the Rope Cloud is a Cold Front.

Suomi NPP VIIRS 0.7 µm Day/Night Band image

Visible imagery during the day on 2 January, from GOES-East, below, shows that the Rope Cloud maintained its structure as it continued pushing eastward towards the Florida Peninsula.

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

(Added: Portions of the Rope Cloud persisted into the early morning hours of 3 January 2013, as shown by the Day/Night Band image from Suomi/NPP VIIRS, below)

Suomi NPP VIIRS 0.7 µm Day/Night Band image

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GOES-15 6.5 µm water vapor channel images (click image to play animation)

McIDAS images of GOES-15 6.5 µm water vapor channel data (above; click image to play animation) showed the intensification of a deep low pressure system that was moving northward in the western Gulf of Alaska during the 31 December 2012 – 01 January 2013 period. Strong storm-force winds and high seas associated with this storm played a role in the grounding of the Royal Dutch Shell Kulluk oil drilling rig around 9 PM local time on 31 December (or 06 UTC on 01 January), just off Sitkalidak Island close to Kodiak Island’s southeast shore. PADQ denotes the location of the Kodiak Airport on the northeastern part of Kodiak Island.

POES AVHRR 12.0 µm IR images

A sequence of three AWIPS images of POES AVHRR 12.0 µm InfraRed (IR) data (above) showed the storm as its center was just south-southwest of Kodiak Island. In addition, a comparison of the 01 January 2013 00:16 UTC 0.86 µm visible channel and the corresponding 12.0 µm IR channel images is also shown (below). Surface reports were plotted on the satellite images — the peak wind gust at buoy 46077 located just northwest of Kodiak Island in the Shelikof Strait was 51 knots or 59 mph at 00:16 UTC (3:16 PM local time on 31 December), and ship NZPO located just southeast of Kodiak Island reported a sustained wind speed of 55 knots or 63 mph at 00:00 UTC (3:00 PM local time on 31 December).

POES AVHRR 0.86 µm visible channel image + 12.0 µm IR channel image

A time series of surface report data from Kodiak Airport PADQ (below) indicated that a peak wind gust of 47 knots or 54 mph occurred at 04 UTC and 09 UTC on 01 January (or 7 PM and Midnight local time on the night of 31 December).

Surface observations at Kodiak (PADQ)

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

A comparison of 250-meter resolution MODIS true-color and false-color Red/Green/Blue (RGB) images from the SSEC MODIS Today site (above) revealed an interesting snow cover feature (snow appears as white on the true-color image, and cyan on the false-color image) surrounding a small body of water in northern Illinois (just north of the cursor) on 30 December 2012.

A closer view of that area using Google Earth (below) indicated that the small body of water was the cooling pond of the LaSalle County Nuclear Generating Station.

MODIS true-color image (displayed using Google Earth)

An AWIPS image of the MODIS Sea Surface Temperature (SST) product (below) showed that SST values were as warm as 55.8 F in the cooling pond — so the flow of colder air (which was generally in the 20s to 30s F) from a variety of directions produced “cooling pond effect snowfall” immediately downwind of the pond.

MODIS Sea Surface Temperature product

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