Snow Patterns?

[jbrouch]

John I Have question I was wondering if you can answer this for me. I remember when I was about ten years old so about 33 years ago. I live just south of Green Bay, Wi about 1 mile from lake Michigan. We used to get so much lake effect snow here just like you get up there. Now all of our snow we get here is either a small alberta clipper, or from the south west and then it is wet heavy snow and melts within a day. Why do we not get any north or northeast winds here in the winter to give us LES any more and will it ever come back around. Summer time all we get is lake winds and it is always cold here.


Thanks John

 

[jd]

Really not sure how to answer this other than to respectfully disagree with how much snow actually fell in the years you are talking about. I could not find any data to show that there was ever a time period when areas just south of Green Bay received 200"+ of snow (our annual average) and saw regular lake effect snows. I have also been professionally doing the weather forecasts and analysis for over 20 years and can say with pretty good confidence that LES on the west side of Lake MI is somewhat unusual, especially when compared to how much LES falls on the east side. This is due to the fact that the prevailing winds over Lake MI. in the winter time are from the NW, not NE.

I am sure that you have memories of a particular season or two from that time frame that were particularly snowy (but still not much more than 100" which would be in all time record territory) and might have even seen quite a bit of LES, but those years were the anomaly, not the norm. In fact, looking over the past few years, the past 4-5 have seen some very heavy snowfall.

FYI, the top 5 snowiest winters for Green Bay are:
1887-88: 147.7"
1889-90: 103.6"
2010-11: 92.6"
2008-09: 87.7"
2007-08: 87.4"
1886-87: 82.7"

-John

 

[ibendwire]

John I Have question I was wondering if you can answer this for me. I remember when I was about ten years old so about 33 years ago. I live just south of Green Bay, Wi about 1 mile from lake Michigan. We used to get so much lake effect snow here just like you get up there. Now all of our snow we get here is either a small alberta clipper, or from the south west and then it is wet heavy snow and melts within a day. Why do we not get any north or northeast winds here in the winter to give us LES any more and will it ever come back around. Summer time all we get is lake winds and it is always cold here.


Thanks John

I too live on lake Michigan south of Green Bay and have done so My whole life (48 years). What John has described is exactlly what I remember. I think it is actually rare that we get lake effect snow on the west side of the lake. We do seem to get some lake enhancement snows from system snows but that usually only amounts to several additional inches of snow. In fact, sometimes the easterly air flow from the low as it passes by can hurt us as the air can be warmed just enough to give us rain instead of snow. That has actually happened several times this year. I am sure John can help much better than I can but in the summer and especially the spring, the lake winds are often created by warmer air traveling over the colder lake which then cools the air. Cold air is heavier than warm air so it sinks and will create an easterly wind right along the lake. Then as the air travels back over the land warms again and rises. Again creating an easterly flow on the ground and a westerly flow aloft. The cooler lake air does seem to lessen as the summer progresses and I am assuming that is due to the fact that the water temperature has warmed creating less of the cooler lake effect winds. My home is about 4 miles west of Lake Michigan while my office is right on the lake. It is not uncommon to have temperatures 10-15 degrees warmer at my house than at my office. Particularly in spring and early summer. Hopefully John will correct me if I have this wrong.

 

[jd]

ibendwire-

You are right. The slightly warmer easterly flow off the lake can sometimes cause the precip to fall in shoreline locations as rain, rather than snow, but can also lead to heavier totals through enhancement if the air is cold enough.

The movement of the colder air from out over the lake to the land in the spring and early summer is the result of a "lake breeze". What happens is that on days with light winds and enough sunshine, the land heats up faster than the water and thus heats the air faster than than over the water. That heated air rises and air needs to fill in, in its place. Since the air is not being heated much over the water and not rising as much, then it flows horizontally from out over the lake to over the land. The air not being warmed as much by the lake is colder than is found over the land.

By the late summer, you can still have a lake breeze, but because the lake temp is warmer, the air over it is not kept as cold, so the cooling effect of the lake breeze is not as noticeable.

-John

 

[ibendwire]

Thanks John. I always wondered why the lake breeze would not usually kick in until later in the morning. That makes sense now.