After a few weeks of little snow and above normal temperatures, it seems as winter is ready to start once again in the northeast. Many can expect a mess Monday night-Tuesday with a combination of snow, sleet, ice and rain all on the table. However, we first have to cover the “appetizer”, as some would say.
Sunday night through Monday: A very weak area of low pressure is expected to develop Sunday night out ahead of our main storm. We have a very healthy 250mb jet streak which will help expand precipitation to the north and west of the developing low pressure. This strong jet streak leads me to believe that precipitation may expand more than is currently forecasted and may be moderate at times in heavier bands.
Although not a lot of snow is expected it will be enough to cause some slippery travel Monday AM during the rush hour especially in southern New Jersey. Attached below is my forecast.
Monday Night through Tuesday: This storm, just like its predecessor, will not be huge but it will be enough to cause disruptions and delays across a more widespread area. I am expecting the front end of the storm to start off at snow before changing to sleet and rain as the low hugs the coast and moves through Long Island and Southern New England. The further north, the more snow and the long you will stay some type of frozen precipitation. Below you can see my synopsis of the event as well as the NAM models take on things.
This storm looks eerily similar to our mid-November snowstorm that kicked off winter that caught many off guard and dropped 6” in New York City. The NAM models is currently showing something similar to that event, where strong lifting and warm air aloft kept areas snow for hours longer than they were supposed to be. Down below you can see the NAM is predicting a large 850mb frontogenesis band forming and moves it northward. Those under that band can expect heavy snow of 1-2” per hour.
This storm is unique as it is a coastal transfer. You can visualize it better with my graphic above and the NAM pressure graphic below. A coastal transfer is when a low pressure of land (usually the mid-west) begins to transfer its energy to a storm developing off the east coast. Therefore the parent low on land begins to weaken as the storm off the coast begins to strengthen. These setups are tricky though as the parent low surges warm air into the northeast because it cuts west while the coastal low tries to wrap cold air as it strengthens. This combined with a strong high pressure to the north supplying extra cold means a true battle between air masses.
Meanwhile, as upper level warm air is flooding our area with warmer air thousands of feet above our heads, the high pressure to the north is driving cold air southward below the warm air layer. With warm air above and cold air below it turns the snow to rain in the warm layer and to sleet or ice as it hits the cold lower layer of air. Eventually, our lower level cold will get kicked out as the low pressure moves northward but the question is how long does it stay and how quickly does our upper level warm layer move in. If our cold stays more locked in we will see higher snow totals before a switch over to rain, if our upper warmth comes in faster but our lower cold stays we will see more sleet and ice. The NAM as well as other models have been trending towards more of a cold air push.
I think it’s a bit too early to pin down specific amounts right now so I made a graphic of where to expect the most snow, heavy moderate and light. I think it does a good job at pointing out specifically where we could be looking at higher totals. Generally, the further north you are, the better chance you see higher snowfall totals. Right now I have NYC on the line of the moderate and light accumulations. I am currently leaning towards the 4” mark but it’s too early to make a call. Philadelphia may see a quick burst of snow before changing to sleet and rain while Boston stays predominantly snow before a changeover to sleet as well as a few rain drops.
Finally my overview shows what precipitation types will be dominant, again, the further north you go the better chance that you will stay all frozen.
Overall it’s going to be a very messy Monday night through Tuesday with a mixed bag of precipitation for everyone. Hope you enjoyed!
More updates to come - MikeBWeather