Good evening everyone.
We got some sunshine this afternoon, but chillier air is on the way. The rest of the week remains on track to be dry, cold, and at times blustery. An arctic cold front moving through the area tomorrow evening could bring a few flurries to Long Island. No surprise accumulations are expected. Highs will be as follows: 40s tomorrow, 20s for Thanksgiving (wind chills in the 10s), 30s for Black Friday, 50s by the weekend.
With a fairly straight forward short-term forecast, let’s look ahead to the long-term.
Last night’s weather models continue the trend of the last week, as we are now seeing long range blocking developing in the North Atlantic. Teleconnections are pointing towards a potentially stormy pattern ahead. The North Atlantic Oscillation is going to be very negative for the majority of the next 2 weeks. We saw this last March for almost a full month, which resulted in 4 powerful Nor’easters. This isn’t exactly the same, but the presence of blocking would favor storm systems tracking to our south and east. It also will mean colder than average temperatures in the Eastern US. The bigger signal to watch for this is the Pacific North America index, which is forecast to be very positive this weekend and peaking early next week. The combination of these two indices points to storminess in the East. Saturday night into Sunday morning we could see some rain as the cold air pulls out and a weak system moves through. There shouldn’t be much with this and the cold air will be long gone by the time that precipitation gets here.
The upper air for Sunday illustrates the blocking and how it impacts the jet stream. Higher pressures build in the northern latitudes and lower pressures are to the south. Short wave troughs are forced to move all along against their natural tendency to want to move northeast into Canada and instead are forced to more more to the east.
The blocking pattern has staying power and it is still there as we go out further in time. This will probably create opportunities for more storminess into the first week of December. Cold air won’t be an issue on Monday but it could become an issue later next week as the cold flow from Canada increases as a surface high builds in Southeastern Canada and attempts to hold in. Since we have already seen an early snowstorm, it will probably be wise to keep an open mind as this pattern develops.
Have a great evening!