1:55 PM | The latest on the upcoming colder weather pattern in the Mid-Atlantic and current sunspot activity
Paul Dorian
Discussion
November continues to run below normal in terms of temperatures in the Mid-Atlantic region and all signs point towards a cold finish to the month with two separate outbreaks of Arctic air. The first outbreak will occur this weekend and it will result in the first widespread, albeit rather short-lived, “lake-effect” snow event of the season so far in places downstream of Lakes Erie and Ontario. Snow flurries/showers and even heavier squalls will occur from late Friday night into early Sunday in the Appalachian Mountains from West Virginia to New England, and a flurry can make it all the way down to the suburbs of the big cities along I-95. After a slight relaxation in temperatures on Monday and Tuesday, another widespread cold air outbreak is expected by the middle of next week and this will send temperatures to well below normal levels from the Central Plains to the Mid-Atlantic coast. Looking even further ahead, there are signs for more cold air outbreaks during the month of December based on the overall pattern change that is now underway. Specifically, the North Atlantic Oscillation (NAO) is about to tank deeper into negative territory which often promotes numerous cold air outbreaks into the northeastern part of the country. The NAO index was talked about at length in the winter outlook video (home page) released several weeks ago as to one of the reasons why a cold and snowy winter is predicted for the Mid-Atlantic region.
Meanwhile, as far as the sun is concerned, yesterday we talked about two large sunspot regions called AR1619 and AR1618 that are now facing the Earth in a pretty direct fashion. AR1618 has now grown to a region 10 times the size of the Earth and it has been active during the past 24 hours resulting in M-class solar flares that appear to have propelled coronal mass ejections towards Earth. If so, the impacts would likely occur on November 23rd with the chance then for some high-latitude auroras. More eruptions are possible from both of these sunspot regions over the next 24-48 hours.