bluewave

This is certainly the most extreme snowfall gradient between Albany and NYC for early December. Time Series Summary for Albany Area, NY (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Snowfall Dec 1 to Dec 11 NYC Snowfall 1 2019-12-11 24.5 1.8 2 2003-12-11 19.2 14.0 3 1977-12-11 13.9 T 4 1926-12-11 12.7 9.4 5 2014-12-11 11.7 1.0

Yeah, a weak and well timed SWFE type storm would be the best bet. I am not sure if that Euro NAO chart you posted uses the same methodology as the official CPC data we rely on. I know several weather model vendors that have their own custom teleconnection indices that vary from the CPC. So non CPC sources can have a big difference from those GEFS forecasts due to calculation methodology alone.

Yeah, that’s usually the case. Models really struggling with where to put the ridges and troughs near the end of the 6-10 day forecast. Looks like each model handles the fast Pacific flow slightly differently. This period is right after the 2nd storm. .

Weak SWFE’s have been the best December snowfall performers in NYC since 2011. So it’s important for that wave to come out less amplified to make it interesting for NYC and the coast. We may not have a good handle on the actual amplitude for several more days.

Root for the 2nd storm to act more like a weak SWFE rather than a more amplified system. The weekend storm becomes a strong 50/50 low So we need the 2nd system to stay flat enough so cold high pressure holds on over New England. Really amped up systems will be too warm in this pattern.

Longer range, it will be interesting how the falling IOD impacts the general tropical forcing and MJO.

We had a really sharp shift in the mean December NAO state after 2010. While there were occasional -AO drops, it has been very difficult to sustain a -NAO pattern in December. Every year after December 2010 featured a +NAO. So our last high impact benchmark blizzard track was on Boxing Day 2010. We have had plenty of success with benchmark snowstorms in JFM. Last year was the exception to that.

That would be nice. We are going to need a strong and sustained -NAO drop at some point this winter to get a more active benchmark rapidly deepening storm track. These transient wave breaks can only do so much with the very active Pacific split flow pattern. We tend to do better with MJO related -NAO drops and start warming events.

The dominant storm track continues to be cutter and hugger. All our major storms this month tracked through the Great Lakes or right across the area. The next 2 storms look to take the same type of track. It will be interesting to see if we can get the benchmark rapidly deepening storm track more active in JFM. Dec 1-10 Next 2 storms

Now that the heavier band moved to my east, the patches of pavement in SW Suffolk which were were white are becoming wet again.

We could see the theme of the event from the weekend model forecasts. Most showed NYC falling to just above freezing. So you knew that if the rates were too low, there wouldn’t be that much accumulation even on colder surfaces. Those 10:1 snow charts are often overdone for areas that can’t fall to freezing when precipitation starts as rain.

Why? The comments about the snow not sticking on the pavement were for NYC with temperatures at 33 and 34 degrees. Long Island got heavy enough rates and temperatures falling to freezing. Like I said yesterday, this is why Long Island does better in rain to snow situations than NYC. But NYC can beat Long Island with snow changing to rain.

The temperatures made it down to 32 here in SW Suffolk like the models were showing last few days. All the colder surfaces are covered with some paved areas wet and others white.

I don’t really trust the models with storm details like until they come within the 120hr time frame. Since small changes or errors can make a big difference.

The Euro looks like the only model showing such a strong 50/50. The GFS and CMC are weaker. So those models have less cold high pressure over New England.

It has the weekend storm becoming the 50/50 low. So cold high pressure holds on over New England. The Euro would be a nice front end thump if it verified like that. While it’s still a long way out, it’s something that theoretically could work in this pattern. We just need that 50/50 to hold on long enough. Otherwise, the high will scoot east too fast and later runs could correct warmer.

Yeah, Long Island tends to do better than NYC in rain to snow situations. NYC can beat Long Island when storms begin as snow and end as rain.

This looks like the first 2 years in a row for NYC to reach 50 inches of precipitation this decade. Monthly Total Precipitation for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 2019 3.58 3.14 3.87 4.55 6.82 5.46 5.77 3.70 0.95 6.15 1.95 2.69 48.63 2018 2.18 5.83 5.17 5.78 3.53 3.11 7.45 8.59 6.19 3.59 7.62 6.51 65.55 2017 4.83 2.48 5.25 3.84 6.38 4.76 4.19 3.34 2.00 4.18 1.58 2.21 45.04 2016 4.41 4.40 1.17 1.61 3.75 2.60 7.02 1.97 2.79 4.15 5.41 2.89 42.17 2015 5.23 2.04 4.72 2.08 1.86 4.79 3.98 2.35 3.28 3.91 2.01 4.72 40.97 2014 2.79 5.48 3.67 7.85 4.37 4.26 5.59 2.25 1.21 5.77 4.51 6.04 53.79 2013 2.76 4.25 2.90 1.31 8.00 10.10 2.84 2.85 2.95 0.36 3.15 4.85 46.32 2012 3.23 1.37 0.96 3.56 5.38 2.97 4.21 2.91 4.39 2.92 1.81 4.80 38.51 2011 4.93 3.47 6.19 5.35 5.11 3.25 3.03 18.95 9.39 6.09 3.05 4.00 72.81 2010 2.08 6.69 10.69 2.99 3.01 2.20 2.60 4.14 3.67 4.91 2.15 4.24 49.37

Maybe the North Shore of Long Island does best if the NAM CAD works out like this.

There may be another storm around the 17th. Root for the storm this weekend to become the 50/50 for it. That could allow high pressure to stay anchored over the Northeast. But I am weary of day 8 colder solutions. We have seen these correct warmer closer in recently.

It’s been an active last few years. NYC is on track to reach 50 inches of precipitation for the 2nd year in a row. Monthly Total Precipitation for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 2018 2.18 5.83 5.17 5.78 3.53 3.11 7.45 8.59 6.19 3.59 7.62 6.51 65.55 2019 3.58 3.14 3.87 4.55 6.82 5.46 5.77 3.70 0.95 6.15 1.95 2.69 48.63

The dominant story since 2018 continues to be the raging Pacific Jet. Next soaking rainfall possible on the weekend.

I.63 in Wantagh so far.

It’s been a while.The last 1.00”+ liquid equivalent snow event in NYC during December was in 2010. Data for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Date Precipitation Snowfall 2010-12-26 1.09 12.2 2010-12-27 0.52 7.8

Currently looks like the best chance for NYC accumulation should be the colder surfaces like the grass in Central Park.