It is way too early to be talking about and forecasting wintry events, but here we are on October 25th discussing not one, but two potential storms systems over the next five days. Let’s break it down:
A frontal boundary will be forming and stretching from the northeast states to the central states on Wednesday, initially bringing the threat of a few light showers to our area. As we get into Thursday morning, a wave of low pressure will be strengthening along this front in the mid-Atlantic states. Colder air will be filtering down on the northern side of this system as heavier, steadier precipitation falls across the northeastern U.S. While the upper levels of the atmosphere will be cold enough to support snow if this were December, there is inherent warm air still at the surface during this time of year that will keep the precipitation in the form of rain for much of the day. However, as the dynamics and heavier precipitation cool the atmosphere, areas from northern New England down to the Catskills of upstate NY should transition to a wet snow by Thursday afternoon/evening. I anticipate that these areas, particularly higher elevations may see several inches of snow fall when all is said and done Thursday night.
Even areas further south into southeast Massachusetts and much of Connecticut will see their first snowflakes in the air Thursday evening if the current model guidance is correct. As far as our areas are concerned, we are looking at a very chilly rain on Thursday with temps dropping into the 40s. There is a possibility that a few wet snowflakes make it as far south as the higher elevations of northern/western NJ Thursday evening, especially if the colder NAM guidance is correct. By Friday morning, temps will have dropped into the 30s and maybe below freezing in parts of the region.
The next system to watch will be on Saturday and certainly has more interesting implications for the Metropolitan area. A vigorous shortwave will dive down from Canada towards the mid-Atlantic coast and will spawn an area of low pressure. Exactly how strong this wave is and how much it digs into the eastern U.S. will determine whether a weaker storm shoots harmlessly out to sea on Saturday, or a significant storm rides up the East Coast. Several surrounding factors in the weather pattern will determine this outcome. Some of these factors I see favoring a strong nor’easter, while others argue a no-go.
Similarly, we have many computer models arguing for no storm on Saturday while others have been suggesting otherwise. The European model for one has been most consistently showing a strong nor’easter this weekend and although statistically the best performing model, it is on its own with this solution currently. The other models have shown glimpses of this stormy outcome at times though and the American (GFS) computer model has been trending a bit towards the Euro today.
In the stormy scenario that the European model depicts, we would have a windswept cold rain beginning early Saturday across the region. Then, with sufficient cold air aloft and heavy precipitation falling, the atmosphere would likely cool enough to change to wet snow in many parts of the tri-state area (50+ miles away from the coast and in higher elevations). Even down to the coast and in the cities though, a change to wet snow at the height/tail end of the storm would be a reasonable possibility if things panned out perfectly. Accumulations could occur in the inland and elevated northwest suburbs.
Of course if the storm moves out to sea instead, then we are left with partly sunny skies and cool high temps around 50 this weekend. So there are still a ton of details to iron out with this potential system, and although a rare and statistically unlikely occurrence, snow in late October is not unprecedented in this region. I will continue to watch the developments in the coming days and post updates.