It typically is a -PNA which usually is lower than normal heights from AK into the Rockies. El Niño is the opposite. Because of our latitude we can do fairly well in Nina’s, especially if the dateline ridging is more poleward. Sometimes you can get real lucky and get a period of blocking to really make it snowy and turn those lows that would cut, into either SWFEs or Miller Bs that redevelop under SNE. You also can play with fire in that pattern if the troughing out west is really deep and/or a raging +NAO. 07-08 was probably the one winter where the NAO was so positive, it set up confluence to our northeast and forced would be cutters to redevelop more towards the cape and SE MA.
In general, SNE does better when the ENSO phases are on the weaker side. You generally don’t want strong Nino or Nina.