donsutherland1

The updated EPS ensemble guidance for New York City is below. The probability of 1" or more snowfall has declined further. The National Blend of Models currently shows no accumulation for New York City.

Morning thoughts… It will be variably cloudy and mild. High temperatures will reach the lower and middle 40s in most areas. Likely high temperatures around the region include: New York City (Central Park): 43° Newark: 46° Philadelphia: 45° Dry and mild weather will continue through midweek. Normals: New York City: 30-Year: 39.5°; 15-Year: 40.3° Newark: 30-Year: 39.9°; 15-Year: 41.1° Philadelphia: 30-Year: 41.3°; 15-Year: 42.2°

The next several days will be largely dry and mild. Afterward, a storm could bring some rain to the region Friday into Saturday. There remains a low probability of measurable snowfall in New York City, but such an outcome is not assured. Following the storm, a seasonably cool air mass will overspread the region. However, milder weather will follow quickly. 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 December 28. 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 -0.87°C. La Niña conditions will likely persist through mid-winter before fading to neutral conditions. The SOI was +9.80 today. The preliminary Arctic Oscillation (AO) was -1.226 today. On January 7 the MJO was in Phase 7 at an amplitude of 0.669 (RMM). The January 6-adjusted amplitude was 0.997 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 97% probability that New York City will have a warmer than normal January (1991-2020 normal). January will likely finish with a mean temperature near 40.6° (6.9° above normal).

Prospects for measurable snow in New York City during the January 13-15 period remain low.

Winter 2022-2023 is poised to become just the 8th winter on record where Central Park had seen no measurable snowfall through January 9th.

Given the discussion about snowfall and Boston's climate, some 100-year charts are below. Select findings: Winter temperatures (December-February) are warming and now routinely average or exceed 32°F Snowfall per day with measurable snowfall has recently been increasing The number of days with 6" or more snowfall has recently been increasing (this outcome would be expected with climate change during initial warming where the atmosphere holds more moisture, but it remains sufficiently cold for snow). If this is the case, one should begin to see fewer days with snowfall but a larger share with significant snowfall. It's somewhat early to make that call, but 5 of the 10 largest stretches without daily snowfall of 1" or more and 10 of the 20 largest stretches without daily snowfall of 1" or more have occurred since 2000. In part, aside from internal variability (which occurs within the context an enhanced greenhouse effect), the increase in the frequency of days with significant snowfall (6" or more), may be contributing to the recent increase in seasonal snowfall.

Only at LGA: 2001-02.

EPS guidance for NYC (January 13-15 period):

Morning thoughts… Light precipitation will end this morning. Clouds will give way to sunshine during the late morning or afternoon. High temperatures will reach the lower and middle 40s in most areas. Likely high temperatures around the region include: New York City (Central Park): 45° Newark: 47° Philadelphia: 47° Dry and mild weather will continue through midweek. Normals: New York City: 30-Year: 39.5°; 15-Year: 40.5° Newark: 30-Year: 40.0°; 15-Year: 41.2° Philadelphia: 30-Year: 41.4°; 15-Year: 42.3°

Statistically, a 50-degree December would be the equivalent of a 45.8-degree January (1991-2020 baseline) at Central Park. The December 2015 average would be the equivalent of a 46.6-degree January. The existing January record, which was set in 1932, is 43.2 degrees.

JFK: None LGA: 1998 and 2002 NYC: 1998

The 18z GFS showed about 1" of snow on Bufkit for LGA. The 18z NAM was lower. The National Blend of Models showed no accumulation. Overall, the idea of little or no accumulation seems reasonable. Thus, there is some potential for the first measurable snowfall of the season tomorrow in New York City, but such an outcome is not guaranteed.

Advancing cloud shield.

Clouds will increase overnight and light precipitation will overspread the region. Light precipitation will continue into tomorrow. New York City and coastal areas will see some light rain and snow. Little or no accumulation is likely. Interior sections could pick up a coating of snow. Mainly dry and mild weather will return following the precipitation. The once moderate support for snowfall during the January 13-15 period diminished sharply. Just 6% of 12z EPS members show 1" or more snow for New York City. 2022 became the 14th year during which New York City received no measurable snowfall through December 31st. During the 13 prior years, mean seasonal snowfall was 16.0" (median seasonal snowfall: 16.3"). Just 8% of those winters rallied to see 30" or more seasonal snowfall. 31% of those winters wound up with less than 10" of seasonal snowfall. Just under half (46%) had 20" or more seasonal snowfall. The lowest seasonal snowfall for those cases of 2.8" was recorded in 1972-1973. The highest seasonal snowfall for those cases was 32.8", which occurred during 2015-2016. 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 December 28. 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 -0.87°C. La Niña conditions will likely persist through mid-winter before fading to neutral conditions. The SOI was +22.15 today. The preliminary Arctic Oscillation (AO) was -1.264 today. On January 6 the MJO was in Phase 7 at an amplitude of 0.996 (RMM). The January 5-adjusted amplitude was 1.041 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 97% probability that New York City will have a warmer than normal January (1991-2020 normal). January will likely finish with a mean temperature near 40.5° (6.8° above normal).

Latest EPS ensembles concerning January 13-15:

That would easily smash the existing record. At Central Park, the record high monthly minimum temperature for January is 25°. That mark was set in 1937.

I would be very surprised if Central Park or JFK had no measurable snowfall this winter. I do think the threat of < 1" is a low probability scenario that can't be dismissed altogether. It's still not a likely one, as I see it, but we'll see how things go. Such an outcome almost happened during Winter 1997-1998 until 5" of snow fell at Central Park and 2.9" fell at JFK on March 22, 1998. That "near miss" with historic futility suggests that had things been just a little different, both locations would have had <1" seasonal snowfall. Maybe this will be the winter? I doubt it. It would probably take a near record warm January courtesy of the strong Pacific jet handing off the baton to a canonical La Niña February followed by a mild March and April to bring about that sorry outcome.

If one looked at Social Media even a few days ago, there was a lot of chatter about a big East Coast snowstorm for the January 13-15 period. Some years--1996 and 2016--were tossed out there, too. Such extreme events are rare. They should not be referenced except carefully. Potential events should not be benchmarked against them without strong and consistent evidence that supports such claims. Exaggerated speculation about potential events damages credibility and misinforms the public. In response to such chatter, I posted EPS ensemble trends to illustrate where things actually stood In fact, as the graph shows: 1. The risk for 1" or more snowfall was moderate at best for New York City. There were no cycles where even half the ensemble members showed 1" or more snow. 2. The risk of 10" or more snow was low (always under 10%). 3. There was no evidence-based case to tie the potential event to either the 1996 or 2016 mega-blizzards. Responding to such chatter, I concluded in a lengthy post on Thursday: ...one can cautiously conclude that January 13-15 offers a window of opportunity to break the measurable snow drought. If things go really well, there might be a small chance of a big snowfall. Much can still change given the timeframe involved. There remain no guarantees. Chatter about big amounts on Twitter or Instagram or Facebook (with or without the posting of long-range snow maps) is pure speculation, as it goes far beyond the bounds of objectivity, regardless of the author. As Dr. Marshall Shepherd put it in a recent tweet in response to a 240-hour ECMWF map, "Snow storm forecasts based on 1 model run 10 days out is fantasy land so please be wary of stuff like this when you see it..." Shepherd's advice should be taken seriously.

The latest ensemble idea concerning the January 13-15 system. Ensemble support for 1" or more for tonight into tomorrow, which had briefly risen to 25% on the EPS, has fallen sharply overnight. High resolution models will provide better insight at this point. For NYC itself, little or no accumulation appears likely given the warm surface and above freezing readings expected. A slushy coating is possible in the nearby suburbs.

Sadly, that’s very likely the case.

Yet another day will very likely pass without New York City seeing a measurable snowfall at Central Park.

Morning thoughts… It will be partly sunny with near to somewhat warmer than normal temperatures. High temperatures will reach the lower 40s in most areas. Likely high temperatures around the region include: New York City (Central Park): 41° Newark: 43° Philadelphia: 44° A weak system will bring a period of light rain and snow to the region late tonight into tomorrow. Little or no accumulation is likely in New York City. Interior sections could pick up a coating. Normals: New York City: 30-Year: 39.6°; 15-Year: 40.6° Newark: 30-Year: 40.1°; 15-Year: 41.3° Philadelphia: 30-Year: 41.5°; 15-Year: 42.4°

Yes. That’s correct.

Harrisburg had 42.6". Atlantic City, Baltimore, Philadelphia, Richmond and Washington, DC did not have 40" of snow.

The EPS ensembles for January 8-9, 2023 in New York City: