Isle Royale makes its own weather

[johnhens]

Saw this on the GLERL/MODIS site. Interesting the clouds over IR.
http://coastwatch.glerl.noaa.gov/modis/ ... 3.250m.jpg

[Backpacker534]

That is very cool, John. I've always heard that the island has its very own weather patterns and this definitely confirms it in a graphical sort of way. There is no doubt that those clouds are forming directly over the island. It would be interesting to hear an explanation from a "geeky", weather-type person as to why this happens.

[fonixmunkee]

That's a perfect representation of how it's like on Isle Royale. Sometimes it really *seems* like you're in a cloud there.

Every time I've been to IR in the spring, the weather has been different. I've been rained on, snowed on, and hailed on. I've had 70 degree days and 20 degree nights in the same 24 hours. Meanwhile, once I get back home, I found out that just a mere 150 miles due east, they had nothing like the weather I had just experienced on IR.

[Ingo]

That is very cool, John. I've always heard that the island has its very own weather patterns and this definitely confirms it in a graphical sort of way. There is no doubt that those clouds are forming directly over the island. It would be interesting to hear an explanation from a "geeky", weather-type person as to why this happens.

The air is forced up as it passes over the island--this cools the air (the higher you go, the cooler it is, usually), and the water vapor condenses to form clouds, since colder air can hold less water.

[Tom]

I'm afraid I'm going to have to stay true to my doubting namesake and say it's an interesting photo, and nothing more than clouds passing through. Without timelapse imagery, it's difficult to say they're not just passing by... (Although Ingo's description of how it normally occurs is correct)

For one, the clouds appear to be cirrus clouds, which would typically form above 25,000 feet. A small island mass that barely stands 1000' around it's surroundings would just have a hard time impacting the atmosphere up that far. For two, I'm afraid that the Isle just doesn't have the necessary mass to impact the weather, imho. While the lake surrounding the Isle certainly impacts the weather we experience out there, the opposite is far less likely.
Last, the photo shows similarly imaged clouds to the East, over an average land mass and the lake, which leads me to believe that whatever the atmospheric conditions were that day jurisdicted the clouds we saw in the sky..

That being said - Like Fonix indicates - Because of being surrounded by the lake (which CAN influence the weather) Forecasts for areas as close as Grand Portage on the mainland are MUCH different than what the island may be like on the same day.

[Engruls]

I know that it is hard to tell what the weather is going to be like on June 26-July 2nd but I was wondering if my 30° F mummy bag would be just fine for those nights....

[Backpacker534]

I know that it is hard to tell what the weather is going to be like on June 26-July 2nd but I was wondering if my 30° F mummy bag would be just fine for those nights....

Obviously everyone has their own comfort level but, I would think that bag would be o.k. at that time of the year. Even if you had a really cool night you would probably be o.k. by just wearing a warmer shirt/fleece to bed and/or maybe a knit hat. For whatever its worth, here are a couple charts you may want to check out regarding the average temps during that time period.

http://wap.weather.com/weather/wxclimat ... h/USMI0431
http://www.isleroyale.info/faq.shtml#Weather

Enjoy your trip!

[Engruls]

Thank you that's very helpful.