Tuesday, December 15, 2009

Greenland Blocking Pattern

This weekend will be cold. High temperatures will be in the lower to middle 30's. This could be the coldest air of the season so far.

We will be tapping in to some of the cold air that has been rooted over southern/central Canada the last couple of days. Air temperatures have dropped to -50° in some spots shutting down airports that normally stay open all year in Canada.

A pattern is setting up that will allow cold "Arctic Outbreaks" to plunge in to the lower 48 states over the next 1-2 weeks. This is due to a Greenland blocking pattern setting up. Yes, I am talking about the Greenland in the northern Atlantic.

Below is a graphic of where the jet stream will be located this weekend. The colors under the jet stream is a representation of temperatures at 850mb or approximately 5,000 feet for Saturday.

Follow the jet stream from the Pacific all the way to just east of Greenland. See how the jet stream rises up over Greenland? That is high pressure in place over Greenland. That is going to cause a traffic jam for weather systems. Due to the ridging taking place over Greenland the jet stream gets backed up and has to go over the country. As it does so, lobes of cold air will get stuck over the Midwest and eastern United States.

Side Note: We are still keeping an eye on the upper-low that could produce snow showers around the area Friday night/Saturday. Temperatures will definately be cold enough for snow. I am a little concerned with with lack of moisture.

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