Snow Possibilities Monday Night – Wednesday: What You Need To Know!

Happy Monday Everyone!

An interesting set-up across Delmarva will give us a chance for accumulating snow Tuesday and Wednesday across parts of the region.

Current surface map shows the low off the coast and the second low moving in from the Great Lakes.

Current surface map shows the low off the coast and the second low moving in from the Great Lakes.

Let’s start with what is happening now. We have two areas of low pressure, one off the coast which is amazing to see from the visible satellite image. A nice center of circulation, almost looking more tropical in nature, rather then the mid-latitude cyclone. A second low is moving into the region from Canada and will keep things unsettled.

Visible satellite image of the low in the Atlantic.

Visible satellite image of the low in the Atlantic.

I just wanted to share an image of this low off the coast. You can really see the power of Mother Nature as this storm strengthened rapidly off the coast on Sunday into Monday.

GFS forecast for Tuesday at 1am. Image Courtesy: WeatherBell LLC.

GFS forecast for Tuesday at 1am. Image Courtesy: WeatherBell LLC.

Let’s now focus on low number two as it will move into the area tonight with some waves of energy around the low. The threat for precipitation will be here tonight, though most of us should stay dry.

GFS forecast for Tuesday at 7pm. Image Courtesy: WeatherBell LLC.

GFS forecast for Tuesday at 7pm. Image Courtesy: WeatherBell LLC.

Going into tomorrow, a more robust wave of energy will swing around the area of low pressure. This will trigger off the chance for a few rain showers and some light snow. The question is: will this storm have enough cold air in place to start this as all snow across northern Delmarva, or will we start with a few rain showers before we transition it over to snow. Secondly, will there be enough available moisture for this wave of energy to really produce accumulating snow.

GFS 850mb temperature forecast for Tuesday at 7pm. Image Courtesy: WeatherBell LLC.

GFS 850mb temperature forecast for Tuesday at 7pm. Image Courtesy: WeatherBell LLC.

One thing is for certain, within all the layers of the atmosphere, the air will be cold enough to produce snow. Notice how our 850 temperatures, or the temperature of the air at about five thousand feet will be well below zero.

GFS surface temperature forecast for Tuesday at 7pm. Image Courtesy: WeatherBell LLC.

GFS surface temperature forecast for Tuesday at 7pm. Image Courtesy: WeatherBell LLC.

With a low developing off the coast by tomorrow evening, it will push warmer air in off the Atlantic, something to watch with regards to snow accumulation. This could warm the hypothetical column of air up to a point where we might change the snow to rain. These are things that we will have to monitor as the snow gets going across northern Delmarva.

GFS forecast for Wednesday at 7pm. Image Courtesy: WeatherBell LLC.

GFS forecast for Wednesday at 7pm. Image Courtesy: WeatherBell LLC.

This storm will be out of here by Wednesday morning, but a surge of much colder air will keep things frigid for the rest of the week into the weekend.

ECMWF snowfall forecast through Wednesday afternoon.

ECMWF snowfall forecast through Wednesday evening.

GFS snowfall forecast through Wednesday afternoon.

GFS snowfall forecast through Wednesday evening.

Now remember, when looking at forecasts from snow from the computer guidance. You are assuming a number of things:

-The snow:liquid ratio will be constant within the storm (10:1), or ten inches of snow will fall for every one inch of liquid.

-The model is assuming that this will be all snow the entire time, there will be no mixing (brings model error into question.)

-You are not looking at the whole picture, just the models interpretation of what is to come. The models are used as a guide for meteorologists to make their forecast.

Timeline of how things will play out with this snow event.

Timeline of how things will play out with this snow event.

Before you need to take this into account, you need a timeline of what is to come. You can expect to see snow across northern portions of Delmarva starting overnight tonight and continue into Tuesday. The heaviest precipitation should fall from Tuesday late in the afternoon and through the evening. All this weather begins to wrap up by the start of Wednesday.

You can expect to see at least a dusting to about an inch of snow from just north of Salisbury and points to the north, I should probably write it as a dustingg of snow through 2 inches. The distance between people seeing no snow to people see a significant snowfall is going to be 40 miles. The heaviest of the snow should fall across northern Delmarva, where you will see 1-3 inches likely, with some backyards picking up on as much as 5+ inches of snow.

As always, there are a lot of moving parts to this forecast and nothing is set in stone. We will see how things play out, but the message here is that there will be some accumulation snow across northern Delmarva as we head into Tuesday.

-Mike