eduggs

We do seem to be trending towards slightly less QPF overall and a shorter duration of ice. The eastward shift and slight separation between the initial WAA and whatever follows is noted. Best case seems to be about 10hr snow with 4-6hrs of that intense, followed by brief zr then dryslot. My heart wants to believe the snowier solutions, but my brain tells me otherwise. To me, the synoptics don't favor a long period of snow. This looks like a lower impact version of December 17. I think sleet taints the snow sooner than modeled and a dryslot saves western areas from a washout. Snow accumulations then come down to how intense the WAA snow bands are. If heavy 1-2" bands materialize some areas could put down a quick 6". But if it's more the moderate .5-1" stuff that I expect, we're looking at more like 2-4" followed by ip/zr away from immediate coast. Mixed signals right now on model guidance. 

In either of the past 2 winters, we're looking ahead here to a major winter storm. It's important to keep that in perspective.

21 minutes ago, Brett said:

Do you think the European is overdone with snow? 

Not much. Maybe by an inch or two with a little more ice. But I think the GFS is a little overdone. I think sub-warning snowfall amounts locally are most likely.

But at this point it's really just guessing.

That's a nice look on the EC. Snow to ice to dryslot. Not much rain away from the coast. I continue to like a model blend. Less snow, less rain, and more ice. That's almost always how it goes around here with a primary into Western PA. But the EC continues to look encouraging for a snowier outcome.

Currently light snow falling in Montville, NJ. Seems to be snowing below the radar.

2 minutes ago, Brett said:

Just looked at the Canadian model on Pivotal the Kuchera snow map doesn’t give that much snow at all may be that it is sleet and freezing rain ?

The GFS has a stronger primary which leads to stronger WAA, a bigger snow thump, and more QPF overall. But it also warms faster as a result and has a shorter duration of ip/zr and more rain.

Big differences on the CMC compared to the GFS. The CMC has a much stronger 2nd and weaker primary. As a result it holds onto freezing or frozen precipitation longer with less rain. I think it has the right idea overall with a weak surface coastal reflection and northerly drain. But I think the GFS will be partly right showing a primary strong enough to keep snowfall below warning criteria, warm mid-levels for significant ip/zr, and eventually shift most areas to rain. 

21 minutes ago, NEG NAO said:

Subtract 3 or 4" for sleet liquid equivalent. Looks like 4-7" of snowfall for our area on the 12z GFS. 

2 hours ago, gpsnavigator said:

Is that sounding really showing a temperature of 60°F at the 850 mb level?

It looks like about 53°F. The dashed temperature lines are slanted at about 60 degrees.

2 hours ago, donsutherland1 said:

It depends on how much predictability one is looking for. The statistical evidence is fairly clear that snowfall is more frequent during negative AO states in the New York City area (and also Middle Atlantic Region).

...

In short, a negative AO, especially one at -1.000 or below, provides a favorable large-scale state for snowfall overall in the Middle Atlantic Region. However, the synoptic details matter. The placement of synoptic features and their evolution occur within the large-scale hemispheric background state and are, at least in part, influenced by the AO.

Don, I agree there is a correlation between local snowfall and the AO. As I said, my issue is the predictability of the AO in the long-term. If today we could know what the AO will be on March 15, we could make a rough statistical assessment of the likelihood of snow on that date. But as it stands we can only make a rough guess.  The correlation only really works in hindsight. 

There is a possibly self-evident but also analogous correlation between snowfall and temperature. When you look back at historical stats, you will find that significant snowfalls are far more likely during periods with below average temperatures than above average. But because of the state of modeling, we don't really have much confidence in specific threats until 7-10 days in advance at the earliest. 

A strongly negative AO can reverse in 2 weeks. And it's not very predictive of specific threats. Negative AO states can be associated with long periods of dry weather or snowfall. Snowfall just appears less likely with positive AO values. Just like how snowfall is less likely with temperatures above 40F. That doesn't mean it will snow if it's cold.

2 minutes ago, wdrag said:

All: the 18z modeling varies.  If the HRRR/GFSV16 works out, all will end the talk of bust for a light event. Both will be better than the 18z NAM/GFS/RGEM. 

 

Right now freezing-frozen precip reaching the ground ne PA near Hazleton (elevated)  and also near I80 NW NJ (515pm ish).  Let's give this a little time before completely throwing in the towel. No matter, it doesn't look like much but enough to be a hazard for the untreated pavement unsuspecting travelers. 

This definitely could be a hazard. I think the light events - esp freezing drizzle - that most people dismiss are sometimes the most dangerous because unprepared travelers can get caught out. But most of us don't care about hazards. We want snow in our backyards.

The EC goes to sleet in and around the City pretty quickly. Several hours of snow well to the north. Overall a much colder solution than the GFS or even the CMC. I would lean towards a warmer solution, but this is still good to see at this stage.

1 minute ago, MJO812 said:

AO looks go go back negative at the end of the month.  I dont think we are done with snow just yet. 

I don't find the forecasted indices to be especially predictive of wintry weather. By the time we get near late month, the AO may no longer be forecast to go negative. So even though there is a modest correlation between AO, PNA, NAO etc states and snowfall, our ability to predict these states far in advance is limited. There are several more weeks of winter left. Let's sew how the model ensembles look as we get closer. Everything is still on the table. 

Talk of past storms is usually a terrible sign for upcoming weather. Honestly a warm and early spring would be nice this year. This might be the first year of my life that I've ever wished for it. I guess I'm still on the fence about it.

13 minutes ago, LibertyBell said:

three 6"+ events here this season, cant really ask for more.

 

Yeah that's pretty solid. But not everyone got three big events. And we could always ask for more

To me this winter so far has been all about the big one we got. That was a great storm. Nothing else was particularly memorable.

The UK is almost all sleet, freezing rain, or rain. Same for the CMC. A little bit of snow at the beginning that inevitably mixes faster than expected. The snow maps are garbage. As others have said they convert total liquid equivalent falling in a non-rain column to snow at 10:1.

Guidance for the next 7 days has really gone to shit. It's hard to see how we snow in any of these setups.

2 okay storms and one great one locally... 6", 19", 5" and then a few nuisance events. It could have been a little better, but it could also have been a lot worse.

2 minutes ago, HVSnowLover said:

Yea this storm may be more favorable for snow/ice than the early week storm as the separation and the highs may allow for some nice cooling and CAD 

I agree especially for a possible burst of snow at the onset. But personally I favor ice or rain for this setup because of the forecasted trof axis (it's really far west) and the high 500mb heights.

GFS rains to Quebec City, but the CMC starts colder with snow to ice and then rain. Either way, to me this has a lot of the hallmarks of a big ice storm. Cold antecedent airmass. Deep snow pack. High pressure over Quebec province. Gulf-origin low that heads inland to western PA.

The past 2 GFS runs had no snow (< 0.1 liquid equiv) in NYC for the entire runs. The v16 GFS was similar through 240 hours. And the CMC was only slightly better. Ensembles have also shifted dominant ptype from snow to mix or rain for the next few threats. I think the expectation should start with not much snow. But there are several threats out there in the mid and long range, and modeled snow is not too far off to our north. But things have clearly shifted less snowy over the past 3 days.

Just now, MJO812 said:

I always wait until the first week of April to declare winter over.

We tracked May snow just last year. But realistically, after Mid March, widespread snowfall along the coastal plain is very uncommon. We have about a month of a window left. And for pack lovers, we have about 2 weeks before the sun will quickly decimate almost anything outside the high country.

Just now, nycwinter said:

you cant be serious..

I am. A lot of people have it in their heads that lots of snow is coming. And it might be. But this is not a slam dunk "pattern." To me it looks icy, then rainy, and then very uncertain towards the long range.

2 minutes ago, MJO812 said:

Its only Feb 11 

We can't count on consistent threats through mid March. There's no guarantee we get any more snow at all. Of course we could also be in for a big snowy finish. Either way, we probably have 4 or 5 more weeks of legit wintry potential. 

The trof axis for the upcoming series of storms looks relatively far west - looks like an ice or rain type setup. If we're lucky it will trend snowier. But we might have run out of our luck for this winter.

mPing and the slightly foggy view on the horizon suggest light snow is moving into the metro west area.

The radar returns in southern Ohio indicate the precip. shield is slightly south of where the 18z NAM and recent HRRR runs showed it (and very sightly south of the 0z NAM). If that translates eastward it might help areas along the southern edge of forecast snow.