bluewave

Models weakened the high pressure at the onset of the storm over New England from a few days ago.

Yeah, the extreme Pacific Jet pattern also causes these big model flips in the longer range.

My concern is the the fast Pacific flow pushes the ridge axis too far east for a decent storm track. While the day 8-10 means have come in colder than a few days ago, that ridge could eventually shift back over the area day 11-15. We really need extreme Atlantic blocking to counter an unfavorable Pacific.

It doesn’t seem like the Pacific is in a hurry to let that happen. Last few runs shifted warmer and more amplified for the second storm early next week. The models seem to be playing catch up with the very fast Pacific flow.

Another soaker on the way as this raging Pacific Jet pattern continues.

The EPS has a low coming through the Great Lakes with cold high pressure behind it. Ridge axis would be too far east for a major storm. May be tough to back that ridge far enough west with such a fast Pacific Jet.

The East Asian Jet extension and fast flow into the West Coast is probably too much for the models to correctly handle.

Hahah...looks like the Euro is playing to its day 8-10 OP too amped up bias with TPV’s near the Northeast. But the pattern does look cold even if the TPV ends up a little further north.

While it’s colder, the disturbance is more northern stream going through the Great Lakes rather than the GFS southern stream. But all models agree in the colder day 8-10 day trends from earlier runs.

The Euro and CMC have the PNA ridge axis further east than the GEFS. So they have waves that amplify too far to the east offshore. Need to slow that Pacific Jet down so the ridge can pull back far enough to the west. But I am weary of relying on that raging Pacific Jet to relax enough to make things work out.

No problem. So far it’s the reverse of January 2016. Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Jan Click column heading to sort ascending, click again to sort descending. Rank Year Total Snowfall ALB Snowfall 1 2011 36.0 34.4 2 2016 27.9 3.3 3 1925 27.4 26.6 4 1996 26.1 28.4 5 1923 24.5 34.6

But the Euro and CMC still don’t have anything. All the models handle the teleconnections slightly differently.

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.