A strengthening low pressure system off the east coast will move northeast on Tuesday, and spread an abundance of moisture across the Hudson Valley. It’s a very complex setup, that is sure to throw a few curveballs. Below is the timeline for the storm, expected accumulations, and then some discussion:
- A mix snow, sleet and freezing rain enters the area from south to north Tuesday morning between 3am and 8am.
- Valley Locations:
- The wintry mix will begin to mix with and likely change to a cold rain (especially in the southern and eastern portions of the valley)
- Precipitation will fall heavy at times from late morning thru late afternoon.
- Precipitation should taper to a light rain / light wintry mix after sunset.
- Temperatures will fall below freezing late Tuesday night, changing the light mix to snow showers by Wednesday morning.
- Periods of light to moderate snow showers continue into Wednesday afternoon.
- Snow will begin near or shortly after sunrise.
- Snow will fall heavy at times from late morning thru the afternoon.
- Snowfall rates of 2 to 3 inches per hour possible
- Strong northeast winds, will blow and drift the snow, also causing very low visibility
- Warm air aloft could cause the snow to mix with and change to sleet and freezing rain for a short time
- Snow tapers to snow showers Tuesday night, and will continue into Wednesday.
Snowfall Forecast (thru Wed AM): (updated Tue. 11/9/14 @8am)
- Zones 1 & 2 (Catskills) : 10 to 18 inches (locally higher)
- Zones 3 & 4 : Slushy Coating up to 2 inches
- Zones 5 & 6 : 2 to 4 inches
- Zone 7 : Slushy Coating up to 2 inches
- Zone 8 : None
- Zone 9 : None
** Snowfall forecasts for all zones except 1 & 2 (Catskills) entirely dependent upon changeover scenario outlined below in Storm Analysis. If air cools enough to support heavy wet snow, the forecast above applies. In locations where dynamic cooling does not occur… snow amounts will be zero.
The storm data continues to come in, and while our official forecast is posted above, we’re seeing some VERY interesting things in the computer models. Case in point, remember what we’ve been talking about from the European model? How it continued to show 850mb (cloud level) temperatures just cold enough to support snow?
As you can see in the above European model image, the Hudson Valley (circled) is depicted as just cold enough for a heavy wet snow. We’ve discussed this option for days, because the European would not let go of the idea. Day after day, it was the only model that stuck to the idea of a heavy… wet… accumulating snow in the Hudson Valley. Here is the NAM (North American Model) from early Monday Morning, depicted are the same 850mb (cloud level) temperatures:
Areas in white are below freezing at cloud level… cold enough to support snow. Unlike the European model… this NAM model image projecting 11am on Tuesday, shows most of the Hudson Valley too warm for any snow, and a cold rain would be falling. How much snow would fall across the Hudson Valley under this scenario? Not much….
However… just a few hours later (Monday night)… the same NAM computer model has a much different idea for the same moment in time. Below is the latest NAM model 850mb (cloud level) temperatures… and notice how much of the area is capable of supporting snow at the cloud level:
Look how much colder the computer model is. It is beginning to look a LOT like the European model above, with most of the Hudson Valley having air temperatures cold enough to support snow… during a time where moderate to heavy precipitation is in the area. What’s the impact? A much different looking snow map:
Now the European model AND the NAM computer model both show accumulating snowfall across the Hudson Valley on Tuesday. Pointing closer and closer toward the scenario we’ve been warning about… that a heavy, wet snow is possible across part of the Hudson Valley on Tuesday. We’ll have more updates later tonight on Facebook… and here on the website early Tuesday.