Are you tired of the cold yet? Although Groundhog Day isn't that far behind us, it's not Punxsutawney Phil we should be blaming for our very cold weather pattern. It's actually negativity! To be more specific, it's a negative reading of the Arctic Oscillation.
The Arctic Oscillation is one of those weather patterns we talk about with the winter outlooks each year. It highlights shifts in features of the polar vortex. The oscillation can play a big role in how our weather plays out in the colder months, but we can only see the pattern's forecast a couple of weeks out.
When the Arctic Oscillation is positive, the jet stream stays north. This keeps the frigid temperatures bottled up in Canada and in the arctic regions.
When the Arctic Oscillation goes negative, the jet stream becomes wavy. The result is some of the arctic air from the polar vortex surging south into the U.S.
This graph from the Climate Prediction Center shows the index went negative in December. Recently, it has gone almost to the bottom of the chart. This is part of the reason we have been cold for an unusually long period of time. The red portion of the graph is the forecast, which does show some improvement later in the month. Models don't agree though, and some keep the negative trend going for at least a couple more weeks.
With little change in the pattern, we can expect our afternoon highs to run closer to our average lows this time of year (at their warmest). The outlook from the Climate Prediction Center keeps the bullseye of below average temperatures near Central Indiana through at least February 24th.
Does all of this cold air already have you thinking warm thoughts? The good news is spring is just over a month away! Hopefully we don't have to wait THAT long to thaw out!