How the arctic air arrives...(1-16-13)
In the last blog we laid out the argument for the change to colder weather here in central New York and most of the eastern United States. Being that the core of cold air won’t be here for another 5 or 6 days, we still have time to fine tune just how cold it's going to be along with the lake effect potential. However, we are getting a clearer picture of how we will transition to this arctic air. Our computer models have a pretty good handle on a strengthening area of low pressure tracking from the Great lakes then northeast into eastern Canada. This low will drag a strong cold front through central New York early Sunday, perhaps even before daybreak. Here is the view from the GFS model.I’ve circled an area on the map where the isobars are packed close together. This is what we call a tight ‘pressure gradient’ This is where we tend to find our strongest winds. I’m also going to include a forecast map from 5,000 feet above the surface and includes wind speeds and directions. It includes 50 knot winds moving across western New York.You might be saying what does the wind at 5,000 feet have to do with our winds down at the ground. On days like Sunday, when colder air is coming into central New York, the atmosphere becomes more efficient in mixing the air in the lower atmosphere. That causes strong winds aloft to mix down to the ground. While we might not be able to mix those winds on the map above all the way down to the ground, I was looking at some other data that suggested that 50 kt winds could be down to 2,000 feet. This tells me the change to colder weather Sunday will be accompanied by winds gusting at times to 50 mph.It looks like wind and colder weather will be the highlight of Sunday but there will be lake effect snow as well. That 5,000 foot level is also critical in determining where the snow is going to be centered and the direction to start the day is westerly so the Tug Hill plateau looks to be under the gun at least Saturday night and the first half of the day Sunday with the potential for heavy snow with some hints from the models that the winds could turn more northwesterly toward Sunday evening.Beyond Sunday, it becomes harder to pinpoint any potential lake effect. Our longer term computer models may do a good job of seeing the big picture with the weather patterns they don’t do as well with the smaller scale features around the Great Lakes that influence lake effect. We’ll have to get closer to next week when our shorter term, mesoscale computer models will be better able to pinpoint the areas for lake effect.
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