Sunday, September 23, 2012

A New Meteorological Phenomenon - Lake Effect Rain

For more than 24 hours now, it's been raining on and off.  I think it stopped and started 18 times yesterday, all of course while I was wanting to get outside and do some work.  It rained overnight, and it's raining this morning, though the dog and I managed a 4 minute break to get outside briefly.

I watch the radar regularly on rainy days, as you can watch the rain approach and later disappear.  You can judge quite accurately when to get outside, and how long you have til the next rain, or whether it's going to rain.  Most rains appear as a line of clouds passing over, or individual storms; they come; it rains, and then they're gone.  But for the last two days the clouds simply keep emerging out over the lake, and come onward in an endless stream all day long.  I've been referring to it as 'emergent rain', 'cause I can actually see the clouds emerging out of nothing on the radar.

So I started googling this morning, and discovered that 'lake effect rain' is just as common as 'lake effect snow', which we get all winter.  And it peaks in late Sept, through Oct, into Nov, in other words, right now.  At this time of year the water in Lake Huron (and the other Great Lakes) is still relatively warm, but we're feeling the first blast of cold arctic air from the north (4 degrees this morning).  The cold air passes over the warm water, and just sucks it up, dropping it again once it passes over the land - lake effect rain, just what I should expect at this time of year.

You learn something new every day.

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