04 October 1999 | Lake Effect Rain Band | GOES-8 Sounder IR Difference Product

RAM name="controls" value="step,startstop,looprock,speed,zoom,toggle">

This is a loop of GOES-8 Sounder IR difference product during the development of a lake effect cloud band over Lake Michigan on 04 October 1999. Calculating the difference between Sounder channel 8 (longwave IR window channel, 11.0 micrometer wavelength) and Sounder channel 5 (longwave IR, 13.4 micrometer wavelength) brightness temperatures generates an estimate of the "Delta-T" over cloud-free regions of the Great Lakes. A higher Delta-T implies greater instability within the lowest 1-2 km of the troposphere, which is more conducive to lake effect cloud band development.

The Eta model analyzed 850 hPa temperatures warmer than -5 C over most of Lake Michigan at at both 00:00 and 12:00 UTC. However, the 00:00 and 12:00 UTC Green Bay WI rawinsondes reported 850 hPa temperatures of -3.7 C and -4.5 C respectively, indicating that the colder air aloft was located farther to the south over Lake Michigan. With lake water temperatures near 15-17 C, the Delta-T was 20 C or greater. Higher temperature differences were indicated over the northern and central portions of Lake Michigan, where the lake effect cloud band initially formed.

Back to the 04 October 1999 Lake Effect Rain Band page