After a rather quite year for snowfall across of much of the northeast and I-95, there are now three threats for snow over the next 4 days. Two of the threats may turn out to be moderate to major storms as well. In recent years we have seen march produce big snowfalls and this year will likely be no exception.
Thursday Night-Friday Morning 2/28-2/29
The first of this multiple round of snowfalls will be the lightest and least impactful. This will occur starting 3-4 am Friday morning in eastern Pennsylvania and spread east reaching New York City by 7am. Below is the NAM models depiction on how things evolve.
As you can see above, (courtesy of tropicaltidbits.com) this snowfall will be a quick hitter and will not be particularly heavy in nature. The best lifting begins to die out as the storm progresses eastward but not before some heavier snow makes it into the Philadelphia region. Regardless, the heaviest precipitation wont lat long and will only be around enough to drop ligt snowfall amounts, my forecast is attached below.
I am expecting 1-3" of snow to fall in western New Jersey and central/south eastern Pennsylvania. I currently only believe Philadelphia and Allentown will receive about an inch of snow but I may be ever so slightly too conservative. Regardless, slippery travel will be the theme Friday morning across the whole area.
Friday Night through Saturday 2/29-2/30
The next storm will likely be slightly more significant in nature will higher impacts. After the initial wave of precipitation on Friday dies out, a weak area of low pressure is expected to organize and push precipitation northward. Some areas will see upwards of 5" of snow from this event and create travel problems.
Snow and sleet will begin to overspread Philadelphia on northward starting around 5pm on Friday reaching New York City by 8pm and Boston by 5am Saturday morning. Philadelphia will go right to sleet then some rain. New York City will see sleet change over to snow as the best lifting moves overhead. Boston will see all snow.
This event is going to have a much greater potential at producing somewhat higher amounts than the last storm as there are better dynamics with the developing low pressure as seen below.
The NAM above, is showing the best frontogenesis developing just south of Long Island and moving to the northeast dropping moderate to heavy snow over a thin strip of southern New England. This is why some regions such as Long Island will likely start as sleet and change back over to snow. As he best lifting air moves overhead it will create heavy precipitation that will cool the boundary layer to be cold enough for snow.
Some models such as the Global models (ECMWF, GFS etc,) are predicting high amounts of 5-8"+ across much of south eastern Massachusetts but I am hesitant to buy into that. Those 10:1 maps are rarely ever right and I am much more keen on follow total positive snow depth maps as produced by the GFS and NAM. These maps are showing much more modest amounts of 3-5" with isolated 6" and to me, are much more believable. Below I attahced my snowfall forecast for this event.
I think a good strip from central Pennsylvania to northeastern Massachusetts will receive a clip of snow with the heavier amounts being centered from New York City to Boston. The jackpot zones are likely to get 3-5" of snow plus that spreads from southern Connecticut through Cape Cod. The 5-6" amounts will likely be centered on the Cape as it will be closest to the developing storm.
Sunday Night through Monday 3/3-3/4
The last storm to impact the region (for now) will be by far the most impactful, spreading heavy snow for a large swatch. It will be the first true wintry nor'easter of the year and details are far from being ironed out.
This storm will be the most complex, the strongest, and feature the most dynamics making for a challenging forecast. It will not be one to cut west of the region, however, it looks to come close enough to cause at least some problems and mixing concerns for coastal areas. The ECMWF is the most aggressive with this idea with an all out rainstorm for most of I-95 and very little snow. This is due to the lack of an NAO block or a positive PNA ridge out to the west. As of right now I am leaning with this model the most bringing the heaviest snow totals north and west of the coast with a mix and rain for coastal areas. The ECMWF did take a step south and east during its latest run this afternoon, yet still held the same general idea.
The GFS, and ICON on the other hand are showing an all out snowstorm for the coast and I-95. I think this is wrong for a multitude of reasons ranging from the GFS's bias of being too flat and progressive with systems to start. Next the GFS has been ever slowly trending north and west towards the European for a number of runs in a row as seen below.
As you can see, the GFS has been moving more northwesterly. It will be interesting to see if that continues over the next few days as I continue to track this threat.
The next reason is, most storms this year have been stronger, more amplified and further west than guidance forecasted. I expect that not to change, and although it will be close for I-95 I do not think this will be the event for them.
Looking in northwestern Canada, clearly there is a trend towards the highest heights moving north, this alows the TPV to move north along with it as well as the cold air. The whole orientation is just not right for a snowstorm, but good timing can possibly change that.
This, along with a lack of high pressure to the north screams to me further west and rain for I-95. The air mass will be cold, yet stale and without a high pressure to keep it locked in place. However, the last minute trends are yet to be seen and I will monitor over the next few days. Below I attached my early outlook for this storm.
For our region I have the highest impacts in northeast Pennsylvania and northern New Jersey into northwestern Connecticut and most of Massachusetts. I believe this areas have the highest chance at seeing the greatest snowfall totals. New York City and Boston are in the medium threat with Philadelphia in the small chance. This will likely be slightly adjusted over the next few days and tomorrow I will release an actual snowfall forecast with a zoomed up region.