GOES-13 6.5 µm "water vapor channel" images

A large and intense cyclone produced widespread heavy snowfall and blizzard conditions across much of the Upper Midwest region on 11 December – 12 December 2010. AWIPS images of 4-km resolution GOES-3 6.5 µm “water vapor channel” data (above) showed the evolution of several important storm features, including a well defined dry slot, deformation zone, and Trough of Warm Air Aloft (TROWAL). The highest snowfall totals with this storm included 26.0 inches at Winona Dam, Minnesota and 23.0 inches at Osceola, Wisconsin.

A closer view using AWIPS images of 1-km resolution MODIS 11.0 µm IR and POES AVHRR 10.8 µm IR data (below) revealed the presence of widespread convective elements are various points in the storm’s life, with many exhibiting cloud top IR brightness temperatures as cold as -65º C (darker red color enhancement).

MODIS 11.0 µm IR and POES AVHRR 10.8 µm IR images

As part of the CIMSS involvement in GOES-R Proving Ground activities, MODIS and POES AVHRR satellite images and products are currently being made available in an AWIPS format for interested NWS forecast offices to add to their local AWIPS workstations (via LDM subscription). For more information, see the MODIS Imagery in D-2D and AVHRR Imagery and Products in D-2D sites. VISIT training lessons are also available for these MODIS and AVHRR images and products.

During the afternoon hours on 12 December, 1-km resolution MODIS false-color Red/Green/Blue (RGB) images created using the 0.65 µm “visible channel” and the 2.1 µm near-IR “snow/ice channel” (below) displayed the extent of some of the resulting snow cover — snow on the ground showed up as varying shades of darker red, in contrast to supercooled water droplet clouds which were the brighter features on the image.

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

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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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