Spring has already shown its head and will continue to do so across the Southeast into this weekend. As the saying goes “Beware of the Ides of March,” and this year the saying holds its own because by the beginning of March we will be looking at a pattern change for the Eastern US. Many factors are at play to why a pattern with is coming.
In the Atlantic there is something known as the North Atlantic Oscillation or NAO for short, and that oscillation is forecasted to tank into a negative phase. When the NAO drops into the negative phase it will allow for a ridge to build over Greenland and for cold air to be pushed into the United States and Europe. By the beginning of March global models are agreeing on a ridge to build over Greenland which gives us more confidence in winter’s return to begin March.
GEFS and EPS 500mb Height Anomaly March 2nd at 00z:
Notice the strong agreement among the two global models with a growing ridge over Greenland and a trough beginning to build and push into the East.
GEFS 500mb Heights for March 2nd at 00z (NH View):
Now, going back to what was said before about the NAO and when it’s negative it oftentimes corresponds to a cold US and cold Europe, notice that Europe is cold and that is a direct result of the negative NAO.
GEFS 500mb Heights for March 3rd at 12z:
Finally, look how by March 3rd the trough begins to push into the East, and the ridge in the Central US decays allowing cold air to force itself into the United States particularly along the East coast.
The pattern is forever changing, but there is a strong indication that winter will return to begin March, hope you all enjoy the warmth while it lasts because changes are on the way, and stay here to watch the changing pattern along with us!