Record March Lake Michigan water temperature? (updated 10 pm 3/20)

Updated 10 pm 3/20

The recent record warmth over the Great Lakes area has resulted in a faster than normal warm up of the cold waters of southern Lake Michigan.  The image below shows the analysis of Lake Michigan surface water temperatures courtesy of NOAA GLERL (Great Lakes Environmental Research Laboratory).   The black star shows the approximately location of the south Lake Michigan Buoy, which is normally deployed from roughly April through November each warm season.   The estimated temperature is somewhere in the 46-47F range, or about 8C.  



In comparison, the chart below shows the historical observed water temperature readings over a 20 year period for the south Lake Michigan Buoy (courtesy NOAA NDBC {National Data Buoy Center}).  The green bar with the dot shows the median value for each month (half of all observations over a 20 year period fall within the green bar).  The dots at the top and bottom show the maximum and minimum water temperature for each month.    Keep in mind that the buoy is rarely in the water as early as March and as late as December, so the data from those months is not as reliable/extensive as the April to November period.  That said, it appears that the current water temperatures are higher than any observed previously from 1981 to 2008 during the month of March (as indicated by red star).  The graphic also suggests that the current water temperatures in south Lake Michigan are also similar to what is normally seen in late May and early June. 

 


Here is the MODIS sea surface temperature image taken Tuesday, at 2 pm CDT. 

Modis image of Lake Michigan surface temperature from March 20, 2012sst legend

Lake Michigan sea surface temperatures have responded to the record warmth of the past week to warm into the low to mid 40s over the nearshore waters from Sheboygan to Kenosha out to mid-lake.   The above image shows mid-lake temperatures in the mid 40s, which corresponds nicely with the above graphical depiction from NOAA- GLERL. 

In contrast, below is the MODIS sea surface temperature image from March 29th, 2011.  Despite it being almost two weeks later, the lake surface temperature remained in the middle 30s. 

Modis image of lake michigan surface temp - March 29th, 2011sea surface temperature legend

 Notice the sharp rise in the below Lake Michigan average sea surface temperature graph since the first week of March.  As of March 20th, temperatures have risen about 4 degrees C above the 30 year average from 1992-2011. 

lake michigan averge temp

The unseasonably warm temperatures are expected to continue for several more days before cooling down for the weekend.


Craven/Kavinsky
National Weather Service Milwaukee/Sullivan WI



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