donsutherland1

A closer look:

Today's high was 17°,

Source: https://repository.library.noaa.gov/view/noaa/53067/noaa_53067_DS1.pdf

It might be low. That was one of the toughest areas. I erred on the side of conservatism. Hopefully, it is low.

New York City: 9.1" Boston: 17.0" Philadelphia: 7.5" Washington DC: 7.5" Hartford: 15.0" Albany: 18.2"

Frigid air covered the region today. The low at Central Park was 9° when the low was just 3°. That was its first single-digit temperature since February 4, 2023. The high temperature in Central Park was 17°. That was its first high temperature below 20° since January 21, 2025 when the high was 19°. It was also the coldest high temperature since December 24, 2022 when the mercury topped out at 15°. The stage is now set for New York City's biggest snowstorm in nearly four or five years. Snow will arrive early tomorrow morning, possibly before sunrise. A significant snowfall is likely in and around the New York City area and surrounding region, even as a transition to sleet is likely. New York City and its nearby suburbs will likely pick up 6"-12" of snow. Areas to the north and west of the City will receive 12"-18" of snow. The central Jersey Shore and eastern Long Island will likely see 4"-8" of snow. Final estimates: Albany: 14"-20" Allentown: 8"-14" Atlantic City: 3"-6" Baltimore: 6"-12" Binghamton: 12"-18" Boston: 14"-20" Bridgeport: 8"-14" Concord: 12"-18" Hartford: 12"-18" Islip: 4"-8" New York City: 6"-12" Newark: 6"-12" Philadelphia: 6"-12" Poughkeepsie: 12"-18" Portland: 12"-18" Providence: 12"-18" Richmond: 3"-6" Scranton: 12"-18" Washington, DC: 6"-12" The last time New York City saw a 6" or greater snowfall was January 28-29, 2022 when 8.3" fell. Its last 10" or above snowfall occurred during January 31-February 3, 2021 when 17.4" accumulated. Arctic air will return to the region as the storm departs. Highs will be mainly in the lower 20s through Friday. Tuesday could again see highs top out in the teens in New York City. the last winter with more than one high in the teens was Winter 2018-19 when there were two such days. Moreover, New York City has the potential to see the temperature dip into the single digits for lows on or more days during this period. Some snow flurries or snow showers are possible Thursday night into Friday morning. Overall, January 20th-February 3rd will likely be the coldest and perhaps snowiest two-week period this winter. The forecast WPO-/EPO-/AO-/PNA+ pattern is typically the coldest pattern in January and among the coldest during the first half of February. A persistently positive PNA will have above climatological risk of moderate or significant snowfalls. For perspective, the coldest two-week period this winter prior to January 20th was January 3-16, 2026 and January 4-17, 2026 with a mean temperature of 30.3°. The snowiest two-week period was December 14-27, 2025 when 7.2" of snow fell. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -0.7°C for the week centered around January 14. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.48°C and the ENSO Region 3.4 anomaly has averaged -0.68°C. La Niña conditions will likely continue into at least late winter. The SOI was -18.88 today. The preliminary Arctic Oscillation (AO) was -2.391 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a cooler than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.6° (3.1° below normal). Supplemental Information: The projected mean would be 2.0° below the 1981-2010 normal monthly value.

Yes. That's correct. From Pivotal Weather: ECMWF, UKMET, and Environment Canada models keep track of precipitation type in a precise way as the model integrates, so we know how exactly much precipitation falls in the form of snow (at least, based on the model’s internal diagnostics). This eliminates any concern about including sleet, graupel, or rain when we compute snowfall for those models. https://home.pivotalweather.com/guides/snowfall

Prior to the warming of the mid-levels tomorrow afternoon, soundings showed a strongly saturated dendritic growth zone (DGZ) between –12°C and –17°C. That is almost ideal for producing large, fluffy dendritic flakes. There was also strong lift and high saturation supporting very efficient snow growth and high snow-liquid ratios, especially in areas with stronger banding. In short, for 3-4 hours there could be snowfall rates of 1" per hour and perhaps 2" per hour at times. That's when most of the snow will fall in and around New York City. The visibility could fall under one-quarter mile during the periods of heaviest snow. Thundersnow seems unlikely in most of the area as there isn't a convective signature in the soundings. It is these dynamics, not 10:1 snow-liquid ratio maps that tell the story of what continues to look to be a significant snowfall in and around New York City. On account of the system's dynamics ahead of the changeover to sleet and the storm's forecast QPF, I have little reason to deviate from my thinking based on today's 12z and early 18z guidance. Through early portion of the 18z cycle, it appeared that even as differences persisted among the guidance, the models were slowly moving toward a consensus with the exception of the 18z GFS. As 100% of individual EPS ensemble members from the 0z and 12z cycles had 6" or more snow, the 18z GFS's < 4" figure is not within the realistic range of possibilities. The strong dynamics noted earlier also suggest that the GFS's solution is unlikely. Overall, a reasonable low-case snowfall for New York City remains 5". A reasonable high case is 12". New York City and nearby areas remain in line for 6"-12" of snow and sleet. Areas to the south and east of New York City could see 4"-8" amounts (even farther south beyond the New York City area, places like Atlantic City should see 3"-6"). General 12"-18" amounts are likely well north and west of New York City, most likely in parts of northeastern Pennsylvania (Pike County, Lackawanna County), Orange County, Dutchess County, Sussex County into at least the northern half of Connecticut. For perspective, the last time New York City saw a 6" or greater snowfall was January 28-29, 2022 when 8.3" fell from a rapidly deepening blizzard that buried parts of Long Island into southern New England under two feet of snow. Its last 10" or above snowfall occurred during the long-duration January 31-February 3, 2021 snowstorm when 17.4" accumulated. Up in southern New England, Boston appears on track to see 14"-20" of snow. If so, that would be that city's biggest snowsorm since the January 28-29, 2022 blizzard, which dumped 23.8" of snow.

Yes. State College has been suffering from a particularly severe snow drought.

Winter Storm Warning Issued for a winter weather event in which there is more than one of the following: snow, sleet, and ice (freezing rain), and one of the warning criteria is met. The warning criteria for snow is 6 inches expected in a 12 hour period, or 8 inches expected in a 24 hour period. The warning criteria for ice is accumulations meeting or exceeding 1/2 inch. A winter storm warning may also be issued for heavy snow combined with strong winds of 25-34 mph that will cause blowing and drifting of the snow. A warning may still be warranted if the event is expected to exceed advisory criteria, but fall just short of warning criteria and will significantly impact mass transit and/or utilities. https://www.weather.gov/okx/wwa_definitions

There could still be a warm layer below 700 mb and above 850 mb.

From the Bronx:

Here was the initial inquiry:

So, it wasn't that storm. I am not sure what storm was involved.

I was living in Washington, DC at the time and don't recall that storm. You might be referring to January 26, 1994, but I'm not completely sure.

Maybe this?

For reference, here's the map though 1/26 0z. Typically, if one reduces the amounts by a category at this lead time, it's estimate is pretty good. As snow will continue to fall in parts of the Hudson Valley after 0z, it's current listing of 12"-15" there is reasonable. I think there will be some 18" amounts there.

Wintry mix is a more general description that includes any type of winter precipitation (snow, sleet, freezing rain). Snow/sleet is more specific.

The RGEM is late. Again. Right now, taking into consideration the early 12z guidance, my thinking is that a reasonable worst-case (least snowy) outcome for New York City is 5" (no real change from previous thinking). A reasonable best case is 12" (down 2" from previous thinking). For now, I'm still thinking that a 6"-12" range for storm total snow and sleet captures the most likely scenarios. Well north and west of the City, 12"-18" still appears likely. Areas south and east of the City and its nearby suburbs down to the central Jersey Shore and on eastern Long Island are in line for 4"-8". As a note, I am not fixated on any single model. My thinking takes into consideration the full range. No model has been dismissed at this time. Moreover, 100% of individual EPS members had a 6" or greater snowfall. I do think that the 12z HRRR was too snowy for New York City, but we'll see what the later guidance shows. By 18z and especially 0z, differences among the various models should narrow dramatically. All in all, this will still be New York City's biggest snowstorm in nearly four or perhaps five years. Personally, given the long snow drought, including the record 1,456 consecutive days without a 4" or greater daily snowfall (that includes today), I'll gladly accept the outcome that appears likely. Of course, I appreciate even the smaller events.

At this stage, I'm using a combination of all of them. I think by 18z we'll see some convergence among them. I generally prefer the RGEM except when it's an outlier among the mesoscale models. Once we're < 24 hours out, I start giving more weight to the HRRR.

I agree. I posted it, because a member mentioned that the 10:1 ratios don't reflect further north. I think it's too aggressive and too cold for the I-95 Corridor.

Yes. I agree. The steady snow might not arrive in the Hudson Valley until 13z or 14z (northern Hudson Valley).

On a more serious note regarding the NAM, the RGEM's high-resolution model and most of the global models use 4dVAR (four-dimensional variation) initialization. The NAM uses the older 3dVAR (three-dimensional variation) initialization. The general idea of warmer air moving in to change the snow to sleet in coastal areas and the New York City area and its nearby suburbs is the baseline idea due to lots of support. It's uncertain whether the NAM is overdoing things on account of its older initialization scheme or if it sees something the other guidance doesn't. If it begins to adjust late today (18z or later), that could be an indication that the older initialization process was playing a role. If, on the other hand, the other guidance starts shifting, that will indicate that the NAM, despite its limitations, had correctly resolved some of the details ahead of the other guidance.

Adapted from Tayor Swift's "We Are Never Ever Getting Back Together." We hadn’t synced a single run all month, ’Cause you said you needed space (What?) Then you come around again and say, “NAM, I miss you, swear the PNA’s gonna change, trust me.” Remember how that lasted for a day? You ditch me when the ridge* is gone, Then beg me for that coastal bomb— “Show snow!” you plead. But I’ve evolved, I’m done, I’ve got a mission: sabotage. ’Cause I am never, ever, ever, ever showing snow together. Like, ever. I’m gonna warm-nose every layer, Torch the mid-levels ’til you suffer. I’m never, ever, ever, ever showing snow together. Like, ever. Oh, you blamed me when the PNA stayed negative, Ghosted me for globals, called me “clown guidance,” so repetitive. So now I’m cranking 850s warm, Killing totals storm by storm, And every run you beg and pray— I’ll melt it all away… ’Cause I am never, ever, ever, ever showing snow together. Like, ever. I’ll overdo the mixing, I’ll break your wintry fever. Yeah, we are never, ever, ever, ever getting snow together— Like, ever. *-PNA Ridge

Here's the HRRR's total snowfall map using the model's own assessment of the snow-liquid ratio: