An interesting thing that occurs near larger lakes is the "lake shadow". This is not really a shadow, rather a lack of clouds near the lake while away from the lake, fair weather clouds develop. You can see this on the two images I provided from yesterday's visible satellite imagery (Just for reference, these are both images of Lake Erie).

When it comes to weather, clouds are created by instability, or rising air. As the sun heats the ground, the air lifts, condensing the moisture and creating clouds. When the air is stable there is a sinking motion that occurs, drying the air out, meaning no clouds.

Since the lake water temperature is still only 40 degrees while inland it was in the mid 40's, we see the more stable (sinking) air located over the lake, and in the immediate vicinity of the lake. This, while our inland conterparts are seeing fair weather clouds develop because of the instability (rising motion).

Now you know why the city is a little sunnier than our inland counterparts this time of year. In the winter, when the lake is warmer than the air (and the winds are calm), we see the reverse... clouds over the lake, while inland locations stay sunnier.

The satellite images for this blog posting were provided by NexSat.

Ray Petelin,
WSEE Storm Team Meteorologist