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Originally Posted by Merrymeeting
Weirscam is reporting 54 degrees. Weather Underground says 54. But Black Cat Weather Cam says 44, with lows in the last few hours close to 40. Is the front moving in that fast or is the Weather Cam reading low today?
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To see if a front is passing, check the graphs on the Black Cat WeatherCenter page (
www.blackcatnh.com/weather). Usually when a front has passed you'll see all the graphs showing some kind of change at about the same time, with the telltale sign being a wind shift.
But the island does have its own microclimate. Over the years, the biggest difference I found was that the air temperature doesn't stray too far from the water temperature unless the lake is frozen (and with an insulating layer of snow on top.) Last summer, our highest temperature was 87 F -- recorded on the same day the rest of New England was around 100.
Some other notes on Black Cat Island's microclimate:
- First frost of autumn is usually several weeks after the mainland's first frost, sometimes not until after ice-in. When the rest of the area drops into the 20s for the first time of the season, the water temperature is usually around 50. We'll get down to the upper 30s with pea-soup fog (a result of the air-water temp difference), while everyone else is scraping frost off their windshields under clear skies.
- When the winds on the mainland are light & variable (or calm,) the lake produces its own breeze from the SE at 5-10 mph.
- On summer days there is often a "sundown wind" that arises from the SE about an hour before sunset, picks up to around 25 mph (great time to sail), and drops off to calm about an hour after sunset (don't forget the aux. motor).
- Sometimes there is wind on the lake when there is very little (or much less) wind anywhere else.
- The mountains to the north and south of the lake act as the sides of a bobsled track for storms and wind, even while winds elsewhere take different directions.
- The mountains also act as a funnel, amplifying winds the way alleys in a city do. This was most noticeable in 1999 when Tropical Storm Floyd came up the east coast. The seacoast of NH had relatively little damage while the NW corner of Winnipesaukee had hundreds of trees down.
- This winter, the island experienced the major snowstorms similar to the way the Rochester area did. Even while towns around the lake were getting snow, the island was changing over to sleet and freezing rain. My guess is that when the storms got close enough to kick up the winds from the SE, the "bobsled track" mentioned above started channeling the warmer ocean air farther inland than it was otherwise reaching. The warmer air only had to reach Alton and then it got a free ride up the lake.
A note on WeatherUnderground: It's the same as the WeirsCam, because WeirsCam uses one of WeatherUnderground's self-updating stickers. I think it's from the Weirs Beach weather station and if you want a similar sticker for your site, just look up your favorite weather station on WeatherUnderground (even Antarctica if you want...) and follow the directions for putting its sticker on your site. Black Cat Island is among them.