MODIS 0.65 µm visible image + MODIS false-color Red/Green/Blue (RGB) image

A comparison of AWIPS images of MODIS 0.65 µm visible channel data and a MODIS false-color Red/Green/Blue (RGB) image (created using the MODIS 0.65 µm visible and the 2.1 µm snow/ice channel images) revealed a swath of snow cover from southwestern Virginia all the way to extreme eastern North Carolina on the morning of 05 December 2010 (above).

Storm total snowfall amounts were as high as 3.0 inches with this event, which occurred on 04 December. While only two first-order stations (Greensboro KGSO and Raleigh KRDU) reported 1 inch of snow on the ground at 12 UTC on the morning of 05 December, the MODIS imagery showed that snow cover (which appeared as shades of red on the false-color RGB image) still remained across a number of counties to the east and southeast.

Better detail of the swath of snow cover across North Carolina can be seen using a 250-meter resolution MODIS true-color RGB image from the SSEC MODIS Today site (below; viewed using Google Earth).

250-meter resolution MODIS true-color Red/Green/Blue (RGB) image

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GOES-13 (left) and GOES-12 (right) 3.9 µm shortwave IR images

McIDAS images of GOES-13 and GOES-12 3.9 µm shortwave IR (IR channel 2) data (above) revealed the “hot spot” (yellow to red color enhancement) due to the eruption of the Tungurahua volcano in the South American country of Ecuador on 04 December 2010. The summit of the volcano is located south-southeast of the city of Latacunga (station identifier SELT). According to an ash advisory issued by the Washington DC Volcanic Ash Advisory Center (VAAC), ash was estimated to be extending upward to altitudes about 26,000 feet around this time.

Note that at times there are sight differences in the size and intensity of the volcano hot spot, due to the different viewing angles from the GOES-13 satellite (located at 75º West longitude) and the GOES-12 satellite (located at 60º West longitude). Also note the improved image navigation and registration (INR) with GOES-13, which keeps the volcano hot spot centered at the same location during the image animation.

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NOAA-15 AVHRR 10.8 µm IR image (with surface air temperatures)

The first -40º F (-40º C) or colder surface air temperatures of the 2010-2011 winter season occurred on 30 November 2010 (the last day of the 2010 Atlantic Ocean Tropical Cyclone Season). A McIDAS image of NOAA-15 AVHRR 10.8 µm IR channel data (above) shows a signal of the coldest air (darker blue color enhancement) draining into the lower elevations of the river valleys and the Yukon Flats region. At Fort Yukon (station identifier PFYU), the daily maximum and minimum temperatures were -36º F (-38º C) and -42º F (-41º C), respectively. In contrast to the areas of very cold surface temperatures, cloud features exhibited much warmer IR brightness temperatures (green to yellow color enhancement).

Note the significantly warmer surface air temperatures at a few sites along the arctic coast of both Alaska and the Yukon Territory of Canada — this was due to a low cloud deck that was preventing the strong radiational cooling that was occurring farther inland. AWIPS images of the POES AVHRR Cloud Top Temperature (CTT) product and the POES AVHRR Cloud Top Height (CTH) product (below) showed that CTT values associated with this feature were in the -20º to -25º C range  (yellow to cyan color enhancement), with CTH values of 1-2 km (violet color enhancement).

POES AVHRR Cloud Top Temperature product

POES AVHRR Cloud Top Height product

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GOES-13 0.63 µm visible channel images

McIDAS images of GOES-13 0.63 µm visible channel data (above) revealed several plumes of blowing dust originating in northern Mexico, which then drifted northeastward across parts of Texas and New Mexico during the afternoon hours on 28 November 2010. At El Paso, Texas (located at the center of the image), winds gusted to 52 mph, and surface visibility was reduced to 2.5 miles due to  blowing dust. Farther to the east, winds gusted to 64 mph at Guadalupe National Park.

A comparison of the MODIS 0.65 µm visible channel image and the corresponding 11.0 µm – 12.0 µm IR brightness temperature difference image (below) showed a signal where the airborne blowing dust was the most concentrated (yellow enhancement).

MODIS 0.65 µm visible image + MODIS 11.0-12.0 µm IR difference image

AWIPS images of MODIS 0.65 µm visible channel data and MODIS 11.0 µm IR channel data (below) showed that many of the larger plumes exhibited a slightly cooler (lighter gray) appearance on the IR image.

MODIS 0.65 µm visible image + MODIS 11.0 µm IR image

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