Remember back in early December when I gave my winter thoughts I said there were a few things that really impact our winters. One them being the Polar Vortex. Remember how warm October and November were this year? Note where I circled, that shows a strong polar vortex. When the

polar vortex is strong it keeps all the cold bottled up over the poles as the polar jet strengthens around it. Sometimes that doesn't happen if the stratosphere and troposphere remain disconnected. Generally though, strong polar vortex is not good for us. Thats what we had last

Winter. From about mid December through the rest of the winter the PV went on roids, it coupled with troposphere and it was done. Now look at that graph once we got to December see how that plunged south, notice we turned colder and we scored a snow storm too. Weaker pv

pushes the lower heights/colder air away from the poles and towards the mid latitudes. it increases the chances for block, which we had for this past system. Now look at the forecast for start of January, it's almost at 90% tile in below average against the mean. If true,

it would increase the chances for blocking to continue along with cold/stormy weather. This is only one piece of the puzzle though. Other factors like the MJO play a role in patterns. So if you want increased chance of snow threats, keep the PV weak