Lake Breeze Crosses Southeast Michigan

   Ideal lake breeze conditions were in place across Southeast Lower Michigan during the afternoon and early evening of Saturday, April 28 2001.  Light surface winds and a land-lake temperature differential combined to produce lake breezes off of Lakes Erie, St. Clair and Huron. Surface winds were generally light, in the 5 to 10 mph range.  These speeds held from the surface up through about 2000 feet above ground level.  Temperatures over land had climbed into the upper 50s to lower 60s, while lake water temperatures were running around 50 in Lake St. Clair, the 40s in Lake Erie, and the 30s in Lake Huron.  At 3 pm, airport observations around the region indicated that the lake breeze had not made much inland penetration. 

     The Table below lists the 3 pm wind and temperature observations for selected sites across Southeast Michigan.  The last column indicates whether the sea breeze had passed that location.  For the most part, those sites with an easterly component to the wind (except Grosse Ile where a southerly wind indicates flow off the water) had experienced the lake breeze passage.  The difference in temperature between those locales in the marine air and those still in the "warm" air was not particularly great on this day, although it can be quite dramatic.   

 3 pm Observations
City Temperature (F) Wind (mph) Lake Breeze Passage
Adrian 59 Calm No
Ann Arbor 60 NW 8 No
Bad Axe 52 NE 9 Yes
Detroit City Airport 55 Variable 5 No
Detroit Metro 57 SW 8 Gust 17 No
Flint 59 Variable 6 No
Grosse Ile 54 S 10 Yes
Monroe 55 SE 8 Yes
Mt Clemens 57 SE 8 Yes
Pontiac 59 Variable 6 No
Port Huron 54 NE 12 Gusting 17 Yes
Saginaw 55 N 10 No
Ypsilanti 58 S 6 No


    As the afternoon progressed, the lake breeze began its inland penetration.  The National Weather Service Doppler radar at White Lake, operating in clear air mode, detected the front as it moved inland.  Operating in clear air mode, the radar can detect the presence of lake breeze fronts.  In reality, the radar is actually detecting biota (mainly insects) caught along the lake breeze front.  Here is the radar image from the National Weather Service White Lake office at 533 pm Saturday evening.  The Erie/St. Clair lake breeze boundary extended from about Romeo in Macomb County to near Plymouth in Wayne County just nudging into the far southeast corner of Oakland County.  There is scant evidence of a Huron lake breeze.  An argument could be made that the vertical green line extending north from the Macomb-Oakland County border in Lapeer County is the boundary, but if so, it's subtle at best.

 
    Here are the 5 pm observations from around the region.  The Erie/St. Clair lake breeze has passed through Detroit City and Metro airports as well as Ypsilanti.  Based on the radar data, the front looks to be knocking on Ann Arbor's door.  Winds at both Flint and Saginaw have come around to the Northeast.  At Saginaw, this likely indicates the passage of a Saginaw Bay boundary with perhaps this boundary slipping to Flint.

 5 pm Observations
City Temperature (F) Wind (mph) Lake Breeze Passage
Adrian 61 Calm No
Ann Arbor 60 Variable 3 No
Bad Axe 52 E 6 Yes
Detroit City Airport 56 S 7 Yes
Detroit Metro 57 SE 10 Yes
Flint 59 NE 7 No
Grosse Ile 54 S 9 Yes
Monroe 55 SE 8 Yes
Mt Clemens 55 Variable 6 Yes
Pontiac 60 NW 8 No
Port Huron 54 NE 15 Gusting 18 Yes
Saginaw 57 NE 6 Gusting 16 No
Ypsilanti 60 SE 9 Yes

  At 731 pm, radar and surface observations indicate that the combined effects of a Huron, St. Clair and Erie lake breeze front had penetrated well inland.  Here is the National Weather Service Doppler radar observation at 731 pm, again operating in clear air mode.  This radar image shows convincing evidence of the front pushing through Flint, Pontiac, and even Adrian.  Surface observations at 8 pm confirm the radar data.

 

 8 pm Observations
City Temperature (F) Wind (mph) Lake Breeze Passage
Adrian 55 SE 12 Yes
Ann Arbor 52 SE 7 Yes
Bad Axe 45 E 6 Yes
Detroit City Airport 52 E 13 Yes
Detroit Metro 52 S 6 Yes
Flint 52 E 20 Yes
Grosse Ile 50 S 6 Yes
Monroe 55 SE 8 Yes
Mt Clemens 52 S 5 Yes
Pontiac 53 E 14 Yes
Port Huron 43 N 9 Yes
Saginaw 53 E 8 Yes
Ypsilanti 50 SE 7 Yes

 


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