Thursday, November 12, 2015

Seiche Alert!

By: Lee Grenci , 6:30PM,GMT on November 12,2015






Strong southwesterly winds associated with a deep low-pressure system moving across the northern Great Lakes region this morning (15Z surface analysis) will produce a seiche across Lake Erie later today and tonight. By definition, a seiche is a standing wave that oscillates back and forth across large lakes and harbors.

I always used my childhood antics to describe a seiche to my students. As a child, I would move back and forth in the bath tub until I got a nice standing wave. Of course, there was sometimes spillover, and, one time, enough water leaked into the ceiling of the living room below. Yes, while my parents were watching television! And, yes, I got the belt strap for that little stunt!

Below is the animation of the model analysis and 12 hourly forecasts of 10-meter streamlines and 10-meter isotachs (in knots) from the 16 UTC run of the Rapid Refresh.


The Rapid Refresh model analysis and hourly forecasts (for 12 hours) of 10-meter streamlines and 10-meter isotachs (in knots) from the 16 UTC run of the Rapid Refresh. Courtesy of Penn State.

Note how the streamlines parallel the long axis of Lake Erie. In a nutshell, strong winds associated with the deep low and strong, gusty winds behind the associated cold front will push water away from the western shores of Lake Erie. At the same time, water levels will rise on the eastern end of Lake Erie near Buffalo, NY.

Below is the forecast for water levels on Lake Erie from the NOAA Great Lakes Forecasting System. Note the very low water mark predicted at Toledo, Ohio, this evening (down a whopping six feet) and a concomitant rise of nearly four feet at Buffalo. Look out for flooding along the eastern shores of Lake Erie!


Forecasts for water levels at Toledo, OH, Cleveland, OH, and Buffalo, NY (in feet) from 12Z model data this morning. Courtesy of the NOAA Great Lakes Forecasting System.

The initial "slosh" will dampen with time into "smaller sloshes" as winds start to diminish.

My infamous bathtub seiche as a young boy stopped when my dad yelled as water dripped into the living room from the ceiling. :-)

Lee

P.S. The loop of 10-meter streamlines and isotachs across Lake Erie (and the other Great Lakes, for that matter) can be an effective way to teach students about the difference in surface friction between land and water.

P.P.S. Thanks to former student, Mark Thornton, for pointing this out to me.

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