Quiet mild weather has prevailed for the most part through much of December so far with a few periods of rainfall that have not even begin to put a dent into what will end up a WELL below normal year for precipitation as some are running as much as 9” below normal. It remains no doubt that we are in desperate need of precipitation badly. Its not in the cards for the next few days as High Pressure looks to keep us right around seasonable for this time of year and dry. I am watching a potential storm system for late this weekend into early next week that could make for a snowy scene Sunday as the San Francisco 49er’s come to Gillette Stadium in Foxboro. I’m sure you have heard, ( hopefully from Southern New England Weather ) that a pattern change appears in the works and signs continue to indicate so as The Projection of The North Atlantic Oscillation (NAO) continues to drop along with the potential rise in the Pacific North American Pattern (PNA).
Both elements indicate colder and stormier times lie ahead between now and at least December 27th. That along with finally a loosening grip of domination with the Northern Jet stream which has sent mild air ahead of cold fronts as storms arrive passing to our northwest, seems to be weakening and a more active Southern Jet stream is prone to take over bringing deeper moisture into storms potential tracking up towards the N. East Coast from the Gulf of Mexico and the Southeast united States. The 500MB pattern also suggests this and has for quite sometime regardless of all the Mid-Long Range outlooks that have been floating around now and then for above average temperatures for much of the United States. All reality is that the signs have been consistent just the opposite for some (SNE) and now our Ensemble and Operational weather model guidance is starting to come around late in the game. This is not a surprise though as confidence in weather models always is lower the further out in time and increases as time draws near. This is especially true when other factors disagree amongst each other, ie. Blocking, lack of pacific Northwest data, ect., ect. As far as specific dates and amounts for specific locations, that remains unknown this early in the game, though there is increasing confidence in a weak storm system approaching from The Ohio River Valley late this weekend and a marginally cold air supply parked off to the North of New England in southeast Canada. This should spell out light wintery precipitation coming in late Sunday, possibly becoming a bit enhanced approaching Southern New England early Monday along with a weak trough that could keep lighter precipitation falling in eastern areas. The potential is there for a few inches of snow with this one. Not a blockbuster though as there will be no phase with the Southern Jet Stream. That could change as we approach the mid-later half of next week as a ridge will build near The Four Corners and send a deeper trough , tapping into Gulf of Mexico moisture and sending a strong surface low up the eastern seaboard with a -NAO (Greenland Block) in place. That storm appears around the 19th-22nd timeframe and looks Juicy !
The Official Start to the Winter Solstice is Saturday of next week and we may coincidentally be just getting it going. ~Anthony