Winter is set to return for the next couple of days but a prolonged cold, frigid spell is likely not going to happen. I think a return to more normal weather is going to occur over the final bit of February as one key “winter” index is returning to a more normal pattern. It’s a pattern that has been understood for centuries by ship captains, but only recently has been used in making short range to “mid range 3 month out” forecast.
You may remember in history class as a child learning about the trade routes to the new world. Ships needing to move West and then North to get to the new world would actually sail South first from Spain in order to catch fast moving winds heading west. They would then use strong Northerly winds along the coast to travel to the North to their destination. In order to return home they would travel north to catch fast moving winds moving east. The absolute worst thing that could happen is if the ships journey took them to what they called the “Horse Latitudes.”
These ship captains were using the ever persistent high pressure area that is always hovering over the Atlantic Ocean. It isn’t always in the same place and its positioning has a global effect on weather. If the ridge moves south for the winter than often times the Midwest and Northeast will have mild winters. The ridge moving North means an abnormally cold winter should be expected.
About a month ago I wrote a blog about the North Atlantic Oscillation (NAO). This is basically just a fancy way of judging where the ridge of high pressure is located at. The NAO is judged on standard deviations from normal. It can range from +3 to -3 and the range is due to how strong or weak pressure is at a specific spot in the Atlantic Ocean. If you’re interested in reading more on the NAO you can click this link.
In the previous blog, I cautioned in early December that until the current pattern changed our winter was likely to be a mild one as the coldest air remained well north of the area. Well as of basically last week, the pattern is showing signs of change. While not surging into negative territory which would likely mean an excessively cold next month it appears the NAO has switched to a more neutral position. The neutral positioning likely means we can expect a more average February with temperatures running closer to average. It isn’t likely that this change will make us remember this winter any differently. It will go down as a mild one, but with the potential for 2 – 3 inches of snow over the next 7 days and a more seasonal outlook for the month we may be able to make up some ground when it comes to snow.
