The U.S. finally got a pretty dose of Arctic air, the first widespread airmass of the year. The following are maps of the highs and lows this past weekend....
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgSHeygyFMECec1soi0xPNXRlRK4J4aGiEz4i8MP0lXgiBriT7DdFCpQNWDPNaKZp_wTCr1YlQF30tB_gTdiHwa05PW2SdCvYyPofR2wDAXBPqB0sPX6EotUmY3_2Ff6LkB1Tb9DLTnD58/s1600/Image10.gif)
One reason for the abrupt change was due to a anomalously strong Madden Julian Oscillation (MJO). In earlier posts I had been expecting the turn to colder based on the pattern AND this strong MJO, but the coldest air stayed well east and north of the high plains. The following chart shows that this MJO was 2 to 3 standard deviations above normal, and is forecast to continue that strong as the MJO continues to propagate into the southern Hemisphere.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWFUewcEPA32sf61CfRzTicOF2Fzv7hTnAZVKeMmVz6CfUPeuCFZmw2eKaVwfnK0Wr4OtnYeohe8lAKHL_3XORloXsUBnojh1uAmSZFd17QX73izYQ8zNC3qfZ6VCjgKz65PZDGVKB-rI/s640/MJO.gif)
Meanwhile other teleconnection indices have tanked into the negative, the first time this winter. Both the North Atlantic Oscillation and the Arctic Oscillations have headed deeply into the negative.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5oiriovn38vIMKeV5wgVfTNb8HnSzBoT1LN4RyofcxOuJNQM83ky46iFmLMpDw5hlR8d9DU9qQIb9a_Wm6NpCubZz3cPGXwbkSqdEqmLQesa7S8S_xJhDWqGW6fglP8x26daoGTllaX8/s640/AO.gif)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEJm0BWAicBZuJQUq54pbCv4rNOzOkejgk3nlExqxgxqG-694rf9VFJbUpnk4wlldgxVvJH-Tu6yXgVtN90vRG6NpTCHKaHBz9T1BT7wHXqY7YXzuekcdDMjnnm0cWOB-IRRSm9x9Bpng/s640/NAO.gif)
And here was this mornings snow cover across the country...
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgw-sgQaWTuaN2RnzjxxdLyaeoeiva2Cg2ZZRtImrbz8uYcg4MKM6OEg2nssqqUZgWCYn4kBd8mx4KVHq1v1oikYUAujMz0ERjRoz3L5ue0TBLY_wlQpNyqr271y4OclD9CIYdelR2_su4/s640/snowcover.gif)
Back to the lead statement about a possible storm between the 15th and 18th. Computer models are still struggling to simulate the current state of the atmosphere and areas of forcing. I'm not confident at all, but I still have a hunch we'll see another strong shot of Arctic air into the high plains (by the end of the week) and there still is a possibility of a developing storm. Any development will have to come from a disorganized flow of air across the Pacific AND from high pressure aloft moving "WEST" across the high latitudes near Greenland.
I will update these possibilities on Thursday.
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