Tuesday, November 8, 2016

Fetch of the Lake

I've commented on the lake-effects light recently.  So I checked out the Weather Network to find out more.  Our headline includes a phrase that is new to me - fetch of the lake.  Here's the November warning about storms because the average surface water temperature is at least 3 C above normal. 

"Lake-effect snow is particularly common throughout the months of November and December because it is normally the time of year when the temperature difference between the air over the Great Lakes and the air over land is greatest. Empirical evidence shows us that a difference in temperature between these two locations must be at or exceed 13 C in order for lake-effect snow to become a real concern.

Given this, if the lakes are a few degrees warmer than they usually are this time of year, it will be that much easier for the temperature difference to attain or exceed that important 13 C threshold when a cold airmass eventually moves in, which it invariably will.

Once that threshold is attained, if the prevailing winds blow consistently along the greatest fetch of the lake, you’ve got yourself a perfect set-up for particularly impactful lake-effect snow event for those downwind."

The historic snowfall in Buffalo was at the end of November, and dropped 6 feet of snow two years ago. It received the name 'November.'

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