Sizzling off the press from Elliott:
Looking ahead into next week and the second half of February, there continue to be signs of a large-scale pattern change. However, the magnitude and duration of that pattern change remain rather uncertain. The Madden-Julian Oscillation (MJO).. or an eastward-moving wave of convection between the Indian and western Pacific Oceans.. is currently in phase 7 but should finally progress into phase 8 around Valentine's Day. In stark contrast to phase 7, MJO activity in phase 8 favors colder and stormier weather in the mid-Atlantic States. There is often a 1-week lag effect with MJO forcing across eastern North America, so the brunt of the colder air may not arrive until February 17th-20th. Additionally, the Stratospheric Polar Vortex (SPV), or band of westerly winds enclosing a large pool of extremely cold air that develops 10-30 miles above the ground over the Arctic Circle every winter, may weaken during the second half of the month and get "dislodged" off the North Pole. A strong SPV is often associated with weaker storm systems and a zonal, or less wavy, Jet Stream pattern, but an unstable SPV can sometimes precede cold air outbreaks and signal a stormier weather pattern across central and/or eastern North America 1-2 weeks later. However, this is not always the case, and the cold air can just as easily dump into Europe or Siberia.
Despite the uncertainties, there should be at least one or two more opportunities for a significant (3"+) snowstorm between February 15th and March 5th. I'm also keeping an eye on a potential storm system next Monday into Tuesday, but the air mass to its north will probably not yet be cold enough for snow in the I-81 or I-95 corridors. There won't be a source of cold air over northern New England and southeastern Canada, and the system could easily just slide across the southeastern United States and out to sea. Needless to say, I'm not impressed by this "thread-the-needle" opportunity for snow. At this point, the most likely scenario is for Monday to turn out partly-to-mostly cloudy and still quite mild with highs in the 40s to perhaps 50°F. There's still time for things to change, but I advise winter-weather fans to keep their expectations low. Check back on Thursday or Friday for an update! Oh, and as I mentioned on Friday, a warmer weather pattern should return during the second week of March due to the progression of several different large-scale features. Spring officially begins on March 19th, but it may arrive 10-14 days early this year. The clock is ticking for snow-lovers.. -- Elliott