Since I’ve talked about the winter 2009-2010 forecast a few times already (most recently in NOAA Winter 2009-2010 Winter Forecast), I thought that it might be appropriate to an early-season snow report–a rare lake-effect snow event in western Nevada (Lake Effect Snow Comes to Nevada).
Lake-Effect Snow, Nevada Style
It’s always a gamble (ha!) to forecast lake-effect snow in western Nevada because it doesn’t happen often. It seems as if it would be a natural location for lake-effect snow, with cold air crossing the lake with frequency. Two factors limit the number of instances that lake-effect snow occurs–the size of the lake and the temperature of the lake, and of the two, I believe it’s the water temperature that’s the greater limiting factor.
I haven’t studied the specifics of Lake Tahoe, but it’s a deep, cold mountain lake, so it’s generally too cold to provide the needed contrast for lake-effect snow. A USGS site indicates that the lake temperature ranges from 65-70 degrees (F) during August and September to 40-50 degrees (F) in February and March.
This, logically, would limit the time in which lake-effect snow is possible to a small window in fall, as in the current example highlighted above by Steve on wxtalk.wordpress.com.
This doesn’t mean that the moisture and lack of friction doesn’t result in greater snow in western Nevada in other situations when snow is occurring; that would be snow-enhancement, not lake-effect snow.
NOTE: If you want to read more on Lake Tahoe lake-effect snow, please see the following link, which is from an AMS (American Meteorological Society) conference: http://ams.confex.com/ams/WAF-NWP-MESO/techprogram/paper_22957.htm
–Paul Yeager
