Another cold and blustery day lies ahead of us for our Tuesday. Expect clouds mixed with sun… afternoon highs in the upper 40s, and wind chills near 40°, thanks to strong NW winds. We’ve got all the details in the HVW 5 DAY FORECAST.
But we want to focus this post on the chance for wet snow… yes snow, that is developing. The details of the forecast will likely change as we move through the day on Tuesday, but we just wanted to at least take an early look at the setup…..
We are tracking what for some will be the regions second chance for snow before Halloween, as things get off to a much different start than last season in terms of signals of long term cold and the overall pattern. Much colder air is already begin to settle into the region and it will have a pretty good grip by midweek. High pressure over Canada will help to keep the cold air trickling into the region. By Wednesday night, this high pressure system is located to our NNE, cold air will be filtering down through the Hudson Valley with lows into the 20’s and low 30’s. Just how cold this airmass is, will be one of the keys to the forecast. On Wednesday night a low pressure system will also be approaching the region from Ohio, this storm system will begin to spread moisture into the region just before daybreak, this also becomes an intricate part of the forecast as well. Below is a model image of what I am describing above.
The cold air draining into the valley ahead of the low pressure can lock in due to the topography, this is typically described as a CAD event (Cold Air Damming). The general look of the models Monday afternoon, show the somewhat shallow cold air eroding rather quickly… so this is not likely. However, it may prolong or somewhat aid in some early onset snowfall all the way to the lower elevations.
The keys to this early season snow are…
- The strength of the cold air and…
- The timing of the storm.
The strength of the cold air requires little explanation, but the timing is key because if the precipitation reaches the region before or around daybreak, before the diurnal heating associated with sunrise occurs, snow is more likely in the lower elevations. However, if the precipitation reaches the region later, after the surface temps have warmed, snow is less likely in the lower elevations.
Below is projected temps at 850mb, or about 5000Ft. Anything below 0° is suitable for snow (indicated by white on this map). Thanks to the fresh batch of cold air and the high pressure to the north, the atmosphere is primed for frozen precipitation, lets see how this translates to the surface in the next image…
Temps at the surface are also quite cold, the higher elevations (closer to 850mb) are colder and in a very good setup for a second accumulating snowfall. Across the southern parts of our region (south of i84) temps are a bit to warm for snow, a cold rain with occasional sleet pellets likely along and south of this corridor. To the north and at lower elevations, the first flakes of the season are very possible with this set up, warm surfaces and short duration may not amount to much, but nevertheless enough to put you in the winter spirit (or not).
There is a reason its titled a (Flakey) forecast:
One, because there might be some flakes (duh)….
Two, because there are some key ingredients that have to be just right for this to come to fruition. October snows are rare and require the alignment of multiple atmospheric ingredients. If any one of these factors are missing… it doesn’t happen, especially across the lower elevations. If you are above 2000′ in the Catskills, the chance of snow Thursday AM is likely. Accumulations across the higher elevations may exceed 3 inches… while the lower terrain may see a trace to an inch, depending on elevation and surface.
As you would expect, we’ll be tracking this very closely. We may have a special update during the day on Tuesday, but should anything significantly change, we’ll share the information with you. But one thing is for certain… this winter continues to look nothing like what we saw last winter.