A persistent ridge of high pressure aloft was keeping the interior of Alaska unusually cloud-free, as was evident on McIDAS images of GOES-11 0.65 Âµm visible channel data on 19 September 2010 (above). Temperatures at many stations across the region had been averaging about 10 degrees F above normal during the previous week, with many daily high temperatures in the 60s and 70s F. On this particular day, the high temperatures ranged from 70Âº F (21Âº C) at Holy Cross (in the clear skies of the interior of southwestern Alaska) to only 37Âº F (+3Âº C) at Barter Island (beneath the stratus clouds along the northeast Arctic Coast).
The visible images showed that low stratus clouds and fog were attempting to work their way inland (southward) across the Arctic Slope region of northern Alaska. Widespread stratus clouds also covered much of the Gulf of Alaska, and was affecting some of the coastal regions in the far southern portions of the state. In addition, a smoke plume from a wildfire could also be seen drifting southwestward across the interior of Alaska later in the day.
AWIPS images of the 1-km resolution POES AVHRR visible channel data along with the corresponding Cloud Type, Cloud Top Temperature, and Cloud Top Height products (above) demonstrated how the various cloud features could be further characterized according to their type (for example, fog vs. supercooled clouds vs. cirrus clouds) along with the temperature and height of their tops.