Many of the same ideas will dominate this blog update as rain dominates the weather picture in northern Vermont in the middle of our first week of December. The upcoming pattern continues to have potential on the winter storminess side of the equation, but the cold air which I predicted would under-perform, has under-performed even my low expectations and the forecast for the next 10 days continues to move in a warmer direction.
With that said, there are a couple of opportunities for winter weather over these aforementioned 10 days. Nothing imminent and certainly nothing we can take the bank, but it's something and we have to start somewhere. Though we won't have snow on the ground, we can a nice stretch of dry weather beginning late Wednesday with sunshine featured on part of Thursday and most of Friday and Saturday. Though the air isn't bitterly cold, much of this period should stay below freezing above 2000 feet allowing snowmaking operations to progress. As expected, a weather system will track well south of the region late Friday and the rain/minimal snow will also stay well to our south. There's been a move on the most recent cycle of models to allow a jet stream impulse to undercut the large blocking structure in the jet stream to our north on Sunday. This feature will have an opportunity to use the relative warmth of the Atlantic to intensify into something on Monday. Precipitation is likely to stay south of Vermont with this guy also, but I am not sure we have total clarity on this potential situation yet. It will evolve and it's worth watching as a potential snow producer for someone early next week. After that a bigger weather system is likely to impact the region later next week. We have gained a clearer picture of this likelihood, but models have been trending farther north and warmer with this storm and at least at this juncture, are not moving the the system underneath the Davis Strait block which is a trajectory storms often take in this weather pattern. I am exercising my constitutional right to remain optimistic regarding a potential storm late next week in spite of current models which will most assuredly shift again. This is a pattern that favors a more optimal storm track and often times we can miss precipitation because we are too far north as opposed to worry about rain. That said, temperatures continue to appear above average yet still mostly sub-freezing through at least Wednesday December 14th.
After the potential storm in the later part of next week, the strength of the -NAO starts to recede but not vanish entirely. The emergence of what appears to be some ridging in the Gulf of Alaska would suggest to me the possibility of a better cold air delivery device around the time of the winter solstice (or just before). At face value ensembles are suggesting the potential for storminess more than cold, but most of the teleconnection indices are at least somewhat supportive of both cold and storminess. I have argued that the cold is being held back by a re-energized Pacific and a negative PNA which is a loose measurement of jet stream ridging strength in the western part of North America. We are expected to at least neutralize this by the 19th while other teleconnection indices remain somewhat supportive of more favorable winter weather conditions. What choice do we have but to wait patiently.
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