eduggs

As usual the GFS is pouring cold water on the situation and stalling our momentum.

It feels like we're starting to get a little momentum going today. Let's keep it going tonight.

That could be a high estimate for survival. Getting an accurate estimate would depend on how causes of death are attributed and how many people have been infected. Without accurate and widespread serological testing for COVID antibodies, we won't really have a good estimate. Regardless, it is significantly deadlier than the flu and deadly enough to cause a little anxiety if you are infected. Getting vaccinated is not just important for personal health. It's critical that we get case numbers much much lower. Obviously a high vaccination to infection ratio protects the heard. But it also significantly reduces the number of mutations that occur. Right now, with millions of cases worldwide, there is an increased chance of a mutation creating a "new strain" that is partially resistant to the current generation of vaccines. That would be devastating.

Maybe consider getting your vaccine at or very close to a hospital just in case. And obviously have the EpiPen ready. Fortunately severe anaphylactic reactions have been rare.

Nothing looks very encouraging to me from a winter weather perspective out at least a week, apart from a few chances for flurries. The Jan 21-23 period still holds some hope, but that seems to gradually be delayed and or deamplified (weak upper level support) as we get closer. Obviously things in model world can change quickly, so we track... It's been about 4 consecutive weeks without a decent winter threat, but there is at least another 4 weeks of potential prime winter left.

Yeah, it just really sucks for all the people who can't get the vaccine due to allergies etc and the ~10% who won't develop immunity from the vaccine. That's why we need high resistance and low case loads in the community.

The 21st still looks like a pretty weak signal to me. It's also 8.5 days out. We've had several of these head fakes over the past few weeks, and most threats have faded with time. The wave train continues, with a new system moving through every 2 - 3 days, which might actually be too active with non ideal spacing. The activity looks good and the forecasted trof axis looks promising. Hopefully one of these systems will sharpen up soon enough to impact us... not way out in the Canadian Maritimes. But which one?

The CMC continues to be really wet for Saturday. It's probably overdone, but it seems like we're due for one of these southerly flow soakers. If the CMC is right, that would be some heavy wet snow in the VT mountains and possibly the Adirondacks. Probably also the higher elevations of the Catskills, Berkshires, and Taconics.

It's really not even close. And not just the surface either. The lowest 100mb is torched. It's unfortunate because 500mb looks interesting. I think we would need something pretty extreme to get a wintry outcome around here. Different story in the highest elevations of the Poconos, Catskills, and then up into NE.

The CMC almost pulled off an event on the 16th. It's pretty close to something, and shows what could happen with a higher amplitude trof and a s/w rounding the bend in the deep south. The GFS and Euro don't look hopeless for this period, but still pretty far off. Can't write it off 5+ days off. As others have noted, the following wave (with timing differences between apprx. the 19th and 21st) looks threatening on most 12z guidance today. But there's very little confidence 10 days out obviously. Can't rule out a warm solution or a non-event.

Almost everything with weather is a wildcard. There is huge uncertainty everywhere. There are no extremely strong correlations between indices and local weather. We can't lock in anything except a high likelihood for AN temps at all timescales beyond 1 week.

I don't. But I think the data Don S (and possibly others) posted previously would answer your question. 50% of average or less probably happens something like 20-33% of the time. And seasons with 10" storms are also somewhat uncommon. So we're dealing with a relatively small sample of years. Since 10" is not far below 50% of average, the situation you're describing is basically getting one significant storm in December and then nothing of significance the rest of the season. I'm sure that doesn't happen very often, but there's no reason why it couldn't.

The December 17 event was just one fluke storm. It could have easily ended up as a relatively pedestrian 5" event like places nearby in north-central NJ. Fixating on the supposed correlation between 10" storms and seasonal snowfall in NYC is silly and not statistically sound.

I see no reason we can't stay warm and relatively snowless. If there is a change, I'm concerned it could be back to a "cutter" type pattern with the main trough axis too far west. I see some indications of this toward the end of some recent model runs. I don't trust any climate index based "pattern" talk out past 10 days. I hope for a good change, but I want to see it in range of the mid-range models first.

It's easier to be confident about time periods out beyond the scope of the operational midrange models. Confidence tends to evaporate as we get within range and things don't look as we hoped . Let's get a little closer and see how things look before we get too excited. I did like how things looked on the 0z guidance I've seen so far out beyond day 7.

For the few years that I've been casually looking at them, I consider the weeklies to have a poor track record of identifying actual snow threats. But I think people like looking deep into the future when things in the shorter term aren't going very well.

The CMC shows a major hit for the 13th. Doesn't mean a ton, but it's nice to see a wintry solution. Fairly strong low and long duration. Nice phase on that run.

It seems like there have been more shortwave troughs and ridges than usual over North America so far this winter. I'm not sure if that's real or just my impression. But if true, presumably the models would have a tendency to "flip flip" based on the sensitivity of the interactions between different features. I like the term - unstable pattern - that Walt used.

Good chance Euro joins the consensus or at least moves towards it tonight. Doesn't mean the threat is dead though.

For a while now the upcoming period has looked promising based on forecast indices and anomaly averaging. In fact if you averaged the 500mb heights over the next several days this "pattern" would look fantastic. Yet here we are with most guidance showing no substantial precipitation within 100 miles for at least the next 7 - 10 days. That's why I hate long range forecasting. Sure it might sometimes work out for energy traders, but weather is a local phenomenon. I know that major snow events are statistically more likely during "favorable patterns." But I've seen so many storms materialize out of lousy patterns... And too-many-to-count good looking patterns fail to deliver. The correlation between forecasted future indices and snow in our backyards is just not strong enough for me to get excited about predictions weeks into the future. All that said, we're still within a moderate-sized modeling error of 1 or 2 significant coastal storms over the next 5 days. So it still bears watching. Modeling has actually become so good that I don't have much confidence in a northward shift of the low tracks. If this were 2001, or even 2010, I would still hold onto more hope for this period.

Yeah come on! Why can't models be consistent 16 days out!

It's still a week+ away but the Jan 8-9 period continues to look interesting. The 0z EC and 12z CMC had the storm and intermodel ensembles are suggestive of a coastal storm threat in this period.

I think we're giving causal power to "the block" that doesn't actually exist. The global-scale atmospheric features are interconnected. The upper and lower level features are integrally related. A change in one feature doesn't really force the other... the changes happen in unison. And the jet streams spinning around the globe are like buckling strings. Movement anywhere along the string affects the whole chain. Models don't "see" a block and then adjust. Models forecast a pattern that we describe as a block simultaneously with depicting synoptic features that are placed in concert with that block. If models forecast a stronger block they will also forecast synoptic features that appear to be responding to that block. But that is not the models responding to something tangible that has the power to force weather changes. That is our ability to see into the future evolving in time. The apparent causal connection is just an illusion. Just like the notion that a surface high can force the movement of a surface low. Highs and lows are merely dance patterns linked in a complex choreography with all the features of the atmosphere.

It's a little warm, especially early. But the rapidly deepening low makes up for it. A solution that intense is doubtful though. But that would be some seriously intense snow.

You look pretty snowy to me based on that CMC depiction. Isothermal column pounding pasty parachutes.