Error Margin Very High for New York City Snowfall
02/12/24 10:00am ET
Good morning everyone. I’ll start off by saying I know this isn’t what you want to hear (especially for the snow lovers out there in the NYC area) but this is a very complicated forecast that has A LOT of room for error in either direction.
As we continue to watch a vigorous low pressure system come out of the Gulf states, eventually transferring energy to the coast, our focus remains on very heavy rain and embedded severe weather expected in Georgia, South Carolina, and parts of Florida this afternoon and evening. Expect torrential rain, gusty winds, and isolated severe weather capable of large hail & isolated tornadoes. As of this moment, a Tornado Watch remains in effect for parts of the Florida Panhandle, and we can expect that watch-box to possible get re-issued for areas north and east of where it is now.
We also begin to pass the torch from the GFS and EURO weather models, to the short range NAM and HRRR. This will give us a better picture in regards to how the Northeast and New England will fare as far as snow and cold air. While late evening models last night and early morning models this morning showed a colder picture, the afternoon run has crept back towards a changeover/timing problem for NYC and areas of Long Island. This is why there has to be a human element involved where forecasts don’t change every 4-6 hours with each run.
To put it plainly, there is still an issue as far as timing of our changeover and what’s left when it does. Is it possible we get an early morning changeover with an extended period of heavy snow? Absolutely. However, there’s also the chance that this entire thing duds out for NYC and Long Island, giving folks a slushy trace to 3″. This is why the National Weather Service hasn’t committed to a Winter Storm Warning for NYC and Long Island, while areas that were under a watch are now a warning. For those who don’t know, a winter storm watch is issued when 6″ or more of snow is possible longer than 24hrs out; then changed to a warning if it is expected to start within 24hrs. A winter storm watch issued within that 24hr window, shows a lot of uncertainty on the part of the agency.
For those who see all snow, this will be a heavy wet snow in the 6-12″+ range. Higher elevations will see the best chance for that 12″+ hit, plus areas of higher convection. Depending on how deep we go convection-wise, that 12″+ could be a 12-18″ type snowfall. For NYC and Long Island, it’s going to be very difficult with relatively warm and wet ground since we start off as rain first. It’s going to have to fall hard and fast to make up the difference, and put down enough slush to start having a layer of snow accumulate.
For this reason, I’m staying on the low end, with a bigger problem along the south shore of Long Island and south shore of NYC getting any type of meaningful accumulation. For interior parts of NYC and the North Shore of Long Island, I’m going to go with 3-6″ of accumulation, but it’s going to be tough to get it to pile up on the streets of NYC. All in all, the chance of an upside AND downside surprise is equal, so be prepared for more, and also mentally prepare yourself for a dud (for the snow lovers).
Here is your local forecast for the NYC area sans snow-amounts since it is discussed above –
After some AM sun, clouds begin to increase with highs in the mid to upper 40’s. Lows overnight dip into the low to mid 30’s , with rain developing, possibly mixing with sleet and snow.
Rain and/or mix changes to all snow at some point tomorrow morning, and when that changeover occurs/how much energy is left, will determine how much it can put down. It’s going to have to work for it though, so don’t be surprised either way in terms of final accumulations. Highs in the mid to upper 30’s dropping throughout the day.
The sun returns on Wednesday with a breeze and very cold day. Highs in the low to mid 30’s. We modify a bit for Thursday and Friday, with sunshine, lighter winds, and near 40/low 40 temps. With the temps above freezing, the wet snow should melt fairly quickly throughout this period.
MANY THANKS TO TROPICAL TIDBITS & F5 WEATHER FOR THE USE OF MAPS
Please note that with regards to any severe weather, tropical storms, or hurricanes, should a storm be threatening, please consult your local National Weather Service office or your local government officials about what action you should be taking to protect life and property.