Where's the snow?
Update #478
Hi everyone, thanks for stopping by for this week’s newsletter!
I wanted to start off this week with a bit of Hudson Valley climatology to put some perspective on our “snow drought” so far this cold season.
To do this analysis, I use something called a “reanalysis”, which provides reliable historical estimates of things like temperature, wind, rain, and snow back to the year 1950. This allows for a long-term (70-year) normal to be calculated. Our current snow season can then be contextualized.
I’m calling this a snow curve (similar to a bell curve) — it shows the average snow depth, by day, through the Hudson Valley snow season, which historically has spanned from the end of October through the end of April, with a few exceptions.
There are a couple of key dates that I’ve highlighted:
December 19th (today!) — on average, only 7% of our seasonal snowfall has typically fallen by this date. In other words, we’ve still got 93% of the season to go.
February 10th — the region has typically experienced 50% of its seasonal snowfall by this date.
February 19th — the typical peak of snow depth in the Hudson Valley during an average winter. 62% of the snow season is behind us by that point.
March 19th — the point at which the snow season is 90% done.
While there is significant variability in year-to-year snowfall, the long term trajectory is down slightly. This is consistent with a warmer climate.
With accumulating snow looking relatively unlikely over the next week, it’s fair to say that things are off to a slow start this year.
Heading into the season, climatic factors looked relatively promising for normal or above normal winter snowfall, despite the potential for warmer than average temperatures. Moisture has been the missing ingredient so far.
BUT: there is a long way to go. Things are looking a little more favorable toward cold weather and the potential for snow from the end of the month into January.
Here’s how the week ahead is looking:
This week’s single disturbance is forecast to track through as Santa glides across the night sky on Christmas Eve. Details are a bit hazy, but I’m leaning toward a higher chance for rain than snow at the moment.
A bit of lingering precipitation is possible on Christmas morning, with the potential for a milder afternoon with some sunshine.
Chances are that it will be a green Christmas 🎄, but keep your fingers and toes crossed if you’re hoping for snow 🤞
Other than that, it’s a pretty unremarkable week. A coastal low may clip the Northeast on Wednesday. If it was to take a more westerly track, the forecast could turn rainier, but it’s not looking likely at the moment.
How about the week of the 27th?
When will our snow drought come to an end?! The 2nd half of the week of the 27th (around or after the New Year), could come with a pattern change across the United States — one that favors more sustained cold weather in the east.
It’s thanks to a big adjustment in the pattern in the North Atlantic Ocean, near Greenland, where a large high pressure system has developed — known as a “Greenland block”.
This pattern will encourage the polar jet stream to dip over the Lower 48, transporting colder air and disturbances from Canada.
As to whether this translates to a snowstorm or two, we’ll have to wait and see!
Winter (summer) solstice
The winter solstice is upon the Northern Hemisphere, while the Southern Hemisphere basks in maximum sunshine this coming week.
New York officially welcomes winter at 10:59 am on Tuesday, December 21st.
On this day, at solar noon, the sun’s direct rays fall at 23.4 degrees south of the equator (called the Tropic of Capricorn). This means that the noon sun angle is at its lowest point in the sky of any day of the year.
The Hudson Valley has a day length of about 9 hours and 10 minutes in contrast to the 15 hours and 11 minutes that occur on the summer solstice.
Here in Auckland, we’ll have at most 14 hours and almost 42 minutes of daylight this week.
Have a festive week 🎅🏻
P.S. the update cycle may be a little different through the rest of the year — the next email update may arrive on the 25th
Thanks Ben. Merry Christmas !
Merry Christmas!