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Old 10-19-2009, 01:47 PM   #30
CanisLupusArctos
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Default First snow at Black Cat

The island has seen its first snowfall of the season. Yesterday, depsite a forecast for rain, the storm blew in as snow. We were on its northern fringes all day, and there was no accumulation. However, the storm had the look and feel of any early December storm.

The weather pattern has been one more typically seen in late November or early December. Forecasters have been admittedly struggling with the computer models, which are not programmed to recognize this. They are programmed to consider normal conditions for the time of year, and they also consider deviations seen in the age of modern meteorology.

When the computer models aren't sure what to say, it leaves their human interpreters having to make educated guesses without the same level of computer help they've traditionally depended on.

When the arctic air mass that gave us our snow was first descending into the Rockies from Canada a couple weeks ago, the technical forecast discussions from the weather offices out there were pretty strongly worded and candid, as forecasters admitted to each other that they were looking at something very unusual, and that the temperatures in their final forecasts would have to be adjusted significantly downward from computer guidance as a result. The computers weren't grasping reality, while the people knew.

Similarly, yesterday's storm would have brought rain to the lakes region if it happened in a 'normal' October. The human forecasters stuck closer to that thinking. Last night, I was visiting with friends in Rochester, and we were watching the snow come down outside the window all evening. As the storm departed New England after midnight, radar indicated some moderate snow in a band right along the coast from Portland to Portsmouth.

There are certain rules of forecasting that apply at different times of the
year. This fall, forecasters who've pretended it's December have been forecasting with success.

Some forecasters are more willing to go against computer guidance than others, while some will always stick close to it. There aren't a lot of forecasters who are mentally able to "pretend it's December" when they know it's really October.

Therefore, think of every weather forecast in this area as potentially warmer than it will actually be. For any given forecast that you look at, don't be surprised if temperatures end up being colder, or if a forecast for rain turns out to be snow.

The ski trails at Gunstock are white today. For the summit elevation, October snow isn't unheard of, but it doesn't happen all the time, either.

While October 18 is very early for snow at this elevation (510 feet), we've had October snow two other occasions since 2000. October 2002 brought accumulating snow from here down to Massachusetts during peak foliage. October 20, 2006 brought a nor'easter whose rain changed to snow just before all precipitation ended around 8 p.m.

Quote:
Originally Posted by chipj29 View Post
Yup, you called it right, and I was way wrong. That warm front just never got north of us until Saturday night. I noticed the temp at my house go up about 4 degrees in the early evening.
Thank you. I have to deflect credit though. It was an experiment on my part. I was already aware of other forecasters "pretending it's December" and being right, so I was curious. I didn't actually expect to be right - you made much more sense. When it worked I thought, "OMG it worked... pretending it's December is actually working in October." And that raises the thought, "OMG what will December bring?"
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