February 17 Snowstorm Final Forecast and Analysis

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                    Happy Saturday weather world!

    I hope everyone is enjoying their weekend (and preparing for tonight’s winter storm).

    The snow this year in February has been hard to come by, but tonight will be the first time plowable snow will cause many disruptions in the Northeast – from Philadelphia, through NY/CT, into Boston and Maine.

    Around 17 inches of snow has fallen for the season so far in the NYC metro area. That is still on the low side for snowfall totals around here, but we will add to that total overnight into tomorrow.

    The sun is out now, but that will be soon to change over the next couple of hours. Clouds will roll in quickly, and I expect the first flakes to start flying in and around the NYC metro area around 5 PM. The snow will then start falling harder within an hour or so, with the heaviest bursts of snow falling from 8 PM to 1/2 AM, ending around 5 AM from west to east. During the heaviest part of this storm, snow will be accumulating at 1-2 inches per hour.

    Please see the map below during the height of storm and where 1-2 inches of snow will be falling per hour:

    One thing to note with this storm is the warmer temperatures in place. The reason why this storm will be mostly all snow from NYC and on north is because we have just received a fresh injection of cold air overnight. With that being said, the temperatures have still been very warm this past week. This means that the ground temperatures are warm, so snow will take longer to accumulate on pavements, and have no problem to accumulate on colder surfaces (grass/cars). My below snowfall totals are for the colder surfaces. You can shave around an inch off for pavement accumulations because of this. This also means that in NYC where there is the heat island effect, manhattan roads, for example, will also take longer for snow to accumulate. In the suburbs, that will not be the case. Please, I urge that everyone use cation traveling tonight. If you can stay home, please do so, because it is not worth getting stuck or in any accidents. The snow will be falling the heaviest at the time people will be going out too – so please keep this in mind.

    Here is a simulated radar of what our future weather will look like at the peak of the storm (note the rain along the coastal areas):

    Here are the current weather advisories around the Northeast (Under the winter storm warnings are where the heaviest snow is expected to fall):

    Regarding snowfall totals, I am going with a general 3-6 inches around the NYC metro area. I will increase these snowfall totals once the storm has started to 4-8 inches if i see the heaviest snow bands setting up around the NYC metro area. I will also decrease snow totals to 2-4 inches once I see whee the snow/rain line sets up and if the storm ends up being warmer than normal. Right now though, I like 3-6 inches of snow falling – with more consensus on a lot of 4 to 5 inch spots. I expect isolated amounts of 6 inches of snow where the heaviest snow bands set up. Soutern New England has the best chance of seeing 6 inches or more – CT, RI, and southern/eastern Massachusetts. The Jersey shore and southern Long Island coast will mix with rain, lowering snowfall totals for them to a coating-3 inches. This snowfall will be of the heavy wet variety – making shoveling not so fun Sunday morning.

    Below is the latest NAM model’s output for this storm. It is on the higher side of snow totals, and labels with the purple color where 6 inches of snowfall is possible. If the storm is strong/cold enough this can definitely happen:

            

    On the other hand, below is the latest GFS model snowfall output. Note here, it has only a coating to an inch or two of snow in the NYC metro area. This is because it believes the storm will be warmer, like I mentioned is a possibilty. At this time, I do not believe this storm will be as wam as the GFS says. I am going in the middle of both with 3-6 inches, but will increase or decrease snow totals if need-be once I see the current radar at 8 PM tonight.

    Below are the National Weather Service snowfall amounts (I think they are a tad too high around immediate NYC, but possible if the heaviest snow bands set up there with little to no rain/mix):

     

    These are good snowfall total maps to follow:

    This map below show the area where I believe 6 inches or more of snow is plausible in Southern New England:

    Something to look forward to is the fact that the snow will be melting by Monday/Tuesday with the warmer temperatures coming in next week. Talking about next week, we could hit the mid 70’s, so we have to get through this weekend snowstorm first to enjoy that.

    By the end of February into March the NAO and AO look to be going into a more favorable position (meaning blocking could be coming around, allowing any storm that does come around to sit and spin, dropping heavy snow totals over a foot. Unfortunetley for snow lovers, this current snowstorm tonight has no blocking in place to do that, so it will be in and out quickly). I know next week looks very warm. As I said, we could be entering a more favorable snow pattern into late Feb/early March, but if the weather pattern does not want to change, tonight’s snow could be the last plowable snowfall of the season, so for you snow lovers, try to get out and enjoy it while you can. It will be very snowy around 10/11 PM tonight.

    Enjoy the snowstorm tonight and be safe everyone!

    Snow Codomo

    -Maps provided by Wxbell and the NWS