Significant snow likely to stay to the south of NYC on Wednesday

Good evening and happy Presidents’ Day!

The weak area of low pressure that failed to produce light snow over much of the New York City area has quickly exited off the coast this afternoon. Unfortunately, we have to watch for another system on Wednesday that has the potential to produce another light wintry mix for the area.

Deep northwesterly flow in the mid levels of the atmosphere has already overspread the entire Northeast this afternoon/evening, which has introduced a much more dry airmass into the picture. Clouds have been on a rather gradual decline over the past couple of hours, and should continue to decrease as we get into the overnight hours. Some breezy conditions will continue into the overnight hours, which should limit radiational cooling to an extent. Lows will still be able to fall back well into the 20’s with teens possible off to the north and west of the immediate NYC area.

Make sure to keep an eye out for slick spots on roadways tonight and into tomorrow morning as any leftover standing water will likely freeze overnight! 

3km NAM showing lows dropping back into the lower to middle 20’s, with teens possible off to the north and west of NYC

Bulk of Wednesday’s storm to stay to the south of the NYC metro

Tomorrow (Tuesday) will start off seasonably cold for the AM commute, with temperatures in the lower to middle 20’s. Occasionally breezy conditions will still be present for the first half of the day tomorrow, but should gradually subside as a strong area of high pressure moves into the Great Lakes. This area of high will provide mostly sunny skies tomorrow, with temperatures staying right around normal for this time of year. Expect highs to only get into the lower to middle 30’s in and around the immediate NYC area, with locations off to the north and west likely struggling to break the freezing mark. High pressure will move overhead during the evening/overnight hours of Tuesday, making for near-ideal radiational cooling conditions. Lows will once again fall into the lower 20’s for the immediate NYC area, with teens expected for NE NJ and locations to the north and west.

Wednesday will be a rather complex day as the general theme of this winter season continues. An area of low pressure will be cutting well off to our west over the Midwest, with yet another strong surface high anchored in over the Northeast. Very deep tropical moisture from the Gulf of Mexico/Caribbean will be rushing into the Southeast during the day on Wednesday, causing a large area of precipitation to break out over the Ohio Valley and Mid-Atlantic states. This precipitation will likely have a hard time making it north of Central New Jersey during the early afternoon hours on Wednesday due to leftover dry air from the Arctic high pressure overhead. Warm/moist air will then continue to push up against the area of high pressure as we get into the later afternoon hours/early evening hours. This sustained push of warm/moist air will likely cause an area of light to moderate snow to push in from southwest to northeast for the PM commute on Wednesday.

Snow will likely continue to work it’s way north of the city during the evening hours of Wednesday, just as high pressure begins to shift off the New England coast. This will cause surface winds to quickly flip to the south/southeast, allowing for a much more marginal airmass to overspread the region. Precipitation will rapidly transition from light to moderate snow, to a mix of sleet and freezing rain- then finally changing to plain rain for the majority of the NYC area before midnight. Plain rain will likely continue into the early morning hours of Thursday, before gradually tapering off during the day.

This evening’s NAM model showing the evolution of Wednesday’s messy storm system

While locations off to our south and west may see some significant snow and ice totals from this system through Wednesday, the overall setup is not favorable for the New York City area to see more than a trace to around three inches of snow before changing to a mix & plain rain. Locations off to the north and west of the city may have a tough time seeing much of anything in the way of snow due to the dry air in place likely taking a prolonged amount of time before becoming saturated enough for snow to develop. Additionally, model guidance has been consistently showing the best forcing and snow growth displaced well to our south during the majority of this event, which will further work to dampen snow totals across the area.

While there are still some details that will need to be worked out over the next 48 hours, this system has the potential to moderately impact the PM commute on Wednesday with light to moderate snow and potentially some freezing rain.

We’ll continue to closely monitor this system and put out updates as new data becomes available!

Latest snow total forecast map for Wednesday/Thursday AM

Have a great night!

-Steve Copertino