AT this point if you are looking at MJO. AO. NAO, PNA to make your winter 15-7 day forecast you have fell into a trap! I have been around this for a long time and the models were better in the 80's and 90's then now! Someone came up with these ideas in the last 15 years that work but are never forecasted right . MJO Phase 8 , -AO, PNA favorable conditions, 50/50 Low, Blah, Blah. Folks these are made up for perfect conditions to get snow, they should not be used for long or med term forecasting. To me only SE ridge and PAC Jet are a bigger player.
What i am saying we need to read the maps have skill set that shows us our way to get snow. A lot of times we are just looking at the L or H on the maps, not contour lines , not actual placements of the High pressure , and more studies into the way the PAC, ocean has an effect on our weather. Like placements of LOWS and Highs overall wind direction and the actual flow of air. Most of these are available but we allow the computers to suck us in , without using some real time data and using something I call forecasting skill. which is a learned trait and takes time to study historic weather patterns weather is Hot, Cold, Snowy, rainy, or dry.