Do Early Cold Outbreaks Mean A Hard Winter Ahead for the Eastern US?
Record November Cold Is It A Shot Across the Bow
Record cold covers the Eastern half of the US and this early and rather robust invasion of cold air has lead many to ask whether this means anything for the winter? The snow weenies of course say it does. They are basically split into two groups. One says that it is because they live by the mantra that it MUST SNOW every day from November to May otherwise it was a terrible winter. On the other side of this are the pessimist weenies who are already on death watch that the early cold and any snow in November is the death knell. Last year we had an early invasion of cold in November along with for most areas, the heaviest snows of the winter in mid month and we know what happened. We had subnormal snowfalls for the I-95 corridor though it was above average in areas just north and west of the famed roadway.
Here is the lowdown on November. You really can’t get a direct correlation between what happens in any one month to what happens in the winter. It assumes that what happened before will happen again in exactly the same way and weather simply doesn’t work that way. The data is mixed at best when we look at some major cities and there is simply too much variability in location, topography and a whole host of other factors to make a credible forecast. Cold comes and goes most of the time. Rare is the winter that is cold and snowy from start to finish. There is always volatility. Two of the record years that stand out in my mind for tonight and Wednesday are 2001 & 2013. 2001 was one of the least snowiest. The winter of 2013 was very cold and snowy. It started early and ended late with hardly a meaningful break in the winter action.
That being said lets look ahead in the longer term and we are speaking in terms of a reasonable range of the next several weeks or so. There are some interesting things that models are showing. I have been emphasizing that unlike last year there is no sign of what I refer to as a Pacific firehose jet stream pattern. That is when you have what is almost a straight line flow from west to east across the Pacific and the US. This keeps things warm and mostly wet. When there is cold air the warm jet dislodges it and you get lots of snow to rain events in the heart of winter. So for now that is one positive for snow lovers. The European model loop above shows that the Pacific at the moment at least is very active with lots of traffic and no sign of that dreaded Pacific fire hose and there is no sign of it showing up in the longer term.
The last few weather model runs are rather interesting for the last 10 days of the month in my view. The European in my view was a bit of an eye opener here. First off there is no sign of the fire hose jet stream. In fact the flow splits in the Pacific with an upper low off the coast of California bringing a southern stream jet across the Southern US. In the East we have an upper low complex in Southeast Canada and the upper part of the Pacific split comes around and creates a bit of a Canadian connection with a colder flow into the Northern Plains, Great Lakes and the Northeast. Pressures in general are higher than average in the North Atlantic which is something that is constantly forecast but seems to never happen or if it does it is too far East. There is a strong Atlantic ridge that holds much of this in place. This would suggest that we will see a near normal or even slightly below normal temperature regime from the Plains to the Northeast .
Gfs long range both in the operational and ensemble runs today gets to the same idea but it takes it a day or two longer to get there. One of the bigger keys to the end of November and the start of December could be whether the higher than normal pressures in the North Atlantic lead to a negative NAO. Based on last night’s GFS, it seems to be trying.
One thing to watch closely is the East Pacific oscillation or EPO which goes slightly postive in a few days but hovers not far from the neutral line. A negative EPO like we have now favors cold air in the East. It was stretched to an extreme a few days ago which is leading to the record cold we have now.
As far as storminess is concerned, last winter we had very little storm activity in the Atlantic as everything raced from west to east. In other words we had an Atlantic firehose jet from Virginia to Spain. There seems to be a bit of an increase in storm activity in the Atlantic but we would need to see more. Storms offshore make for a better opportunity for systems to move up the east coast verses out to sea. We have one such system late this week that is likely to slide out offshore with no real impact to the Northeast and Northern Mid Atlantic states.
In summary, I think we have a shot of an interesting pattern developing for late month. Split flows are tough to forecast since you have to worry about two jet streams instead of one. The longer range weather pattern could be a potend of some early winter action if if verifies.
MANY THANKS TO TROPICAL TIDBITS FOR THE USE OF MAPS
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