Yet another winter storm, named Skylar, will impact the area Monday night into Tuesday and will bring snow and gusty winds. This is the third impactful nor'easter that we will have so far this March, or the third nor'easter in just 10 days. The first storm on March 2nd was responsible for damaging winds where winds gusted into the 60s along the coast. Then there was the most recent storm last week that we can all remember. This storm dumped up to 26 inches of snow to southwestern Connecticut, and that heavy, wet snow also led to widespread power outages and several days of school closures. That now leads us to Winter Storm Skylar, this week's storm. I'll discuss the timing, details, the snowfall forecast, and will analyze this storm below.
Winter Storm Warning in effect from 12am through 6pm Tuesday
Snow starts: Between 8pm and 12am Tuesday
Peak intensity: Between 4am and 11am Tuesday
Snow ends: Between 12pm and 3pm Tuesday, snow showers follow through rest of day
Monday night: Low temperatures between 28 and 33 degrees
Tuesday morning: Hovering between 32 and 29 degrees
Tuesday afternoon: Rising into the mid to upper 30s
Widespread three to six inches is currently forecast
Snow Monday night into Tuesday
Wind gusts up to 35 mph, strongest at coast
Isolated power outages
Heaviest snow Tuesday morning
Now that you got the brief overview of the timing, temperatures, snowfall and threats, let's now go more in-depth into your forecast. Another nor'easter will develop Monday morning off the Carolina coast, and will move north-northeast toward the region just off the Northeast coast while rapidly-strengthening. This will be another "bomb cyclone," where the storm will undergo the process of bombogenesis. This crazy word means that the minimum central pressure will fall by at least 24 millibars within 24 hours. By Tuesday morning, the pressure will likely have fallen below 975 millibars. Keep in mind 24 hours before that time period Monday morning, the pressure was at around 1005 millibars. That's greater than a 24 millibar drop! Not only does that mean this storm will intensify fast, but it will drop to a low enough pressure to produce heavy snows to portions of New England as well as strong winds. Below is a neat loop of the pressure drop of this storm from Monday morning through Tuesday:
One of the key uncertainties in regards to this forecast is the exact track of the minimum central pressure of this nor'easter, or the center of this storm. This exact track is extremely crucial to the impacts from this storm, especially the snowfall. Much of the model guidance wants to take this storm near or just southeast of the 40/70 benchmark, although some take it closer to the coast or others take it farther out to sea. This benchmark determines how impactful a nor'easter can be, typically speaking. If a storm tracks northwest or inside of the 40° N, 70° W coordinates, then that would bring mixing concerns to the immediate coast and heavy rain just inland. If a storm tracks southwest or outside of the benchmark, then the heaviest of snow will be confined to the coast. Keep in mind that every storm is different, however. Based on the current forecast track, which is just outside of the benchmark, this storm looks to be the most impactful to eastern New England.
Another uncertainty connected to the track of the storm, which we just discussed, is the snowfall. Snowfall is always super difficult to predict. Elevation, temperature, the atmospheric profile, snowfall ratios, and frontogenesis (lift that allows for heavy snow) are all factors that go into a snowfall forecast. It is pretty hard to know where the heavy snow bands set up, but the model guidance can give you a general idea of where the best frontogenesis or lift may set up. You need lift in order for heavy snow. Based on the NAM model, it shows where those heavy snow bands may set up, as indicated by the red and pink color shading. The heaviest of snow will be closer to the coast in eastern New England because the low pressure is expected to be in closer proximity, but a deformation band may set up on the backside of the storm in our neck of the woods, as shown below. This goes back to the track of the low, however, because if the storm tracks further west than currently forecast, then that could shift all of these expected snow bands to the west as well.
Elevation, temperatures, the atmospheric profile, and snowfall ratios are other factors that go into this forecast, as mentioned above. Typically, the higher elevations receive a bit more snow than at the coast due to enhanced lift. That may be the culprit with this storm as well, but for all locations, this should be an all-snow event. In terms of temperatures, this will be the coldest storm compared to the past two with temperature below, at, or a degree above freezing, but it will still be a wet snow with snowfall ratios at around 10:1. This means that for every one inch of liquid, 10 inches of snow would fall.
Based on all of this discussed so far, I am currently forecasting 3 to 6 inches of snow for much of our area with 6 to 10 inches for eastern areas:
Again, because the track of this low is uncertain, there is still a large spread in possible solutions. The model guidance is indicating anywhere between 1 and 9 inches of snow, as of Monday
morning. This shows that snow is likely and that there is the potential for more or less of snow than currently forecast. There is currently a 40% chance our area receives at least half a foot of snow with this storm.
Lastly, I talked a lot about the uncertainty with this storm, which exists with every single weather event. I want to briefly talk about how this storm will specifically impact you. A light snow is expected to begin Monday evening, likely between 8pm and midnight. Snowfall intensities will increase after a few hours from the start of the event, with a moderate snow beginning early-Tuesday morning and continuing through about noon on Tuesday. The heaviest of snow, where snowfall rates at times may reach 1-2 inches per hour, will be in the mid to late morning on Tuesday (between 6am and 12pm). Then as we get into the afternoon, the snow will taper. Some of the models want this snow to end at around noon while others keep it around to as late as the evening commute in the form of snow showers.
I also get the question if the snow will "stick." It's hard for forecasters to predict whether roads will be impacted. We predict snowfall amounts, not snowfall amounts on roads that may be treated. The key thing with this event is that temperatures will be cold enough Monday night for snow to accumulate on most roads. Once there's at least a coating of snow on the grounds and roads, then that cools the surfaces cooler and allows for more snow to fall. Remember, snowfall amounts are officially measured on a while snowboard every six hours. This allows for most or all of the snow to accumulate and to reduce compaction of the snow, according to the National Weather Service.