The storm continues to be on track to impact our region starting late this afternoon. Snow will start out light and possibly not accumulate, overnight it will increase in intensity and that’s when it is expected that we will see the most accumulations. The snow should exit our area by early Monday morning.
In terms of totals there is still high variability on the models, but overall these look like reasonable calls:
Nassau- 3-6
Suffolk- 4-8 (Possibly more closer to the east end)
NYC- 2-4 (Less in Manhattan more in Queens. The heat island of Manhattan may prevent much accumulation at all on the streets)
Unfortunately the 18Z models just came in, and they moved towards slightly more snow than the last update. They have moved back into the 3-6 and possibly slightly more range. This goes with the theme that I discussed earlier of the models varying widely in their depictions of the system. More updates to come later tonight or early tomorrow morning.
A winter weather advisory has been issued by the National Weather Service for tomorrow’s storm. There is still some variation between models in total snowfall, but the NWS call of 2-4 seems reasonable at this time. More updates later.
... Winter Weather Advisory in effect from noon Sunday to 6 am EDT
Monday...
The National Weather Service in Upton has issued a Winter Weather
Advisory for snow... which is in effect from noon Sunday to 6 am
EDT Monday.
* Locations... Nassau... western Suffolk... and Middlesex counties.
* Hazard types... snow.
* Snow accumulations... 2 to 4 inches.
* Timing... a mix of light rain and snow develops early Sunday
afternoon... then changes to snow late in the afternoon. Snow
will continue through Sunday night... tapering off by Monday
morning.
* Impacts... visibilities will be reduced in spots due to blowing
snow. Travel will remain difficult due to accumulating snow.
* Winds... northeast 10 to 15 mph with gusts up to 20 mph.
* Temperatures... in the lower 30s.
Precautionary/preparedness actions...
A Winter Weather Advisory means that periods of snow... sleet... or
freezing rain will cause travel difficulties. Be prepared for
slippery roads and limited visibilities... and use caution while
driving.
Remember when I said that there’s plenty of time for things to change and that anything could still happen? Well it looks like that may be coming true. Overnight, almost all of the models trended towards the GFS/NAM solution and less snow for the area. I would not say the snow threat is totally gone, since there are still many models showing light snow come through the area on Sunday night into Monday. BUT the threat of 6+ inches of snow is now gone. We’re now talking a maximum snowfall in the range of 2-4 inches and the likelihood of less than that is increasing. This still requires close observation, and we could still trend back to slightly more snow, since there is still a low pressure system just off the coast.
Below are some examples of the wild changes we can see on models in 24-48 hours. Anyone remember the blizzard in January? Models were struggling to firm up totals until the storm began and it ended up tracking a bit further Northwest than originally forecast.
Oh and another bit of good news, which I’ll expand on in a later update: The weather will warm up again next week!
GFS:
This is the GFS from Thursday night, check out the expansive precipitation shield and the low close into the coast.
Now look at the GFS from early this morning, note the low further east, with a smaller precipitation shield. Also check out the shape of the circle around the L, that’s indicative of a low that’s less well organized.
NAM:
Here is the NAM from Friday morning, it has the low tucked into the coast and fairly well organized.
Below is the NAM from this morning for the same time frame as above. Now you see two very poorly organized low pressure centers, with very light precipitation in the area. As a matter of fact, often when you see a depiction such as this no precipitation falls at all.
Finally, here is the NAM forecast for early Monday morning. It does show some light snow in the area, but it may not be enough to really stick around once the sun comes up and the temperatures rise during the day.
The latest modeling continues to indicate that a winter storm will impact the region in the Sunday to Monday timeframe. The timing of the start of snow still varies on the models from mid-day Sunday to early Sunday evening. In regards to totals there is still high variability as well. For now I’m sticking with the 3-6/4-8 idea. However, this is subject to change depending on track and evolution of the storm which continues to vary from run to run of the models.
I should note that the NAM 18z run just came in showing only 1-2 inches in the area. As of now the NAM is an outlier, with no other model supporting its solution. This does show that anything is still on the table, but with a gun to my head I would not rely on the NAM as the model to make a final call.
One piece of good news: After the storm passes through next week looks to warm up, which means any snow that does fall will melt relatively quickly.
I plan on posting further updates this weekend to keep everyone updated.
I’m going to cut right to the chase, and say: Winter is returning
As of this afternoon, all of the major global models have a significant storm impacting our region starting on Sunday. The timing of the start of the storm varies across models from Mid-Late Sunday Morning on the GFS to later in the day on the UKIE/EURO. The timing will have a significant impact on how much snow sticks, and how it will impact Monday for work and school. If verification scores and statistics are what you want to go by the EURO and UKIE should be the models that you focus on.
Currently, the EURO and UKIE have the storm tracking up the coast late Sunday into Monday, and dropping 6″+ of snow on the area, with more to the West and less to the East. The latest EURO model runs are hinting at a chance of mixing from Central Long Island and East. The GFS is showing no mixing, but a slightly weaker low tracking out to sea. The GFS only gives the area about 4″ of snow.
If I had to guess a snow total, and it’s still too soon for this to be accurate, I’d say anywhere from 4-8″ is a reasonable expectation. This is highly likely to change in the next few days as the models get a better grasp of all the features involved and the short range models come into range to show exactly where the freezing line sets up in the upper atmosphere. Stay tuned…
