etudiant

Surely the punch line here is this:  

When freshwater injection on the Southern Ocean is halted, global temperature jumps back within two decades to the value it would have had without any freshwater addition 

Afaik, there has never been a halt to freshwater injections into the Southern Ocean, so this is a totally unverifiable claim.

Add to this a generous 20 year lag time to reach the new equilibrium, there is no way this can be tested or verified within a human lifetime.

Is this science?

Interesting factoid, but how is this relevant to 'American Weather'?

Given the circulation patterns, one could argue that this record merely reflects the warmer than usual winter here in the NYC region.

Is it not reasonable to anticipate a sloppy spring, providing a worthy pendant to a sloppy winter?

After all, the core drivers in the Pacific all remain as before.

If there is a development favoring something sharply different, I'd expect our site experts such as donsutherland1 to give us a heads up. There has been nothing thus far though.

Central Park  perhaps 1", still very thin snizzle continuing, just consolidating the snow cover.

4 minutes ago, LibertyBell said:

lol that's higher than the speed of sound- which is 640 mph through "regular" air at average air pressure, I think?

Sure is, so as the plane max speed is about 0.85 times the speed of sound, it underlines how strong the tail wind was to get over 800 miles per hour ground speed.

4 minutes ago, LibertyBell said:

 

Please add a little explanation for those of us here who don't know what this measures or what it means.

NYC Central Park was around 1.5", with graupel all afternoon. 

Overall, a winter event of little note, but driving was really nasty.

Snow in Central Park seems to have ended at 10.45 am, with accumulation of less than an inch.

This is a 'learning winter', where we all learn humility.

Fact is no model set has performed either consistently or reliably this winter, at least for the NYC area.

Given that there is plenty of computer power available to throw at these problems, it suggests that there are real shortcomings in the models the forecasts are based on. Hope that the folks at NOAA and elsewhere recognize this and try to rework these fundamentals, because until that happens, things will not improve.

There should be a discount factor for longer term forecasts.

So if gfs FV3 projects 4"/hr  for 5 days out, discount by a factor of 5. That suggests modest snow at 0.8"/hr.

Precedent would probably be supportive of that.

2 minutes ago, JerseyWx said:

Then you're a very peculiar person, I must say.

Not at all, rather Gravity Wave is blessed with a full consignment of Celtic genes. 

Think it is really wonderful to see how much more variable our weather can be even over the near term, well beyond our current forecasting skills.

It sure teaches us humility.

That said, what can be learned from this? Are there any elements that we can look at to recognize that the modeling should be skeptically received?

Donsutherland1 has pointed to the absent Pacific blocking for one, what are the others?

1 hour ago, forkyfork said:

the eps has been showing a dream pattern since december. polar blocking with a pac jet undercutting the cold

Sadly that has not translated to any significant snowfall for us NYC residents. Should we expect the balance of winter to be any different?

1 hour ago, Ji said:

everytime you post something, it sounds like your guessing lol. Like when you thought the SOI would drop to -10 a few days ago, and severe blocking would develop. Anyway.....I am optimistic  that your optimism will finally pay off post Feb 10.

Funny, I read them as well grounded evaluations of the current situation.

Particularly appreciated is that these are much more sober than those provided by some of the more opinionated/enthusiastic forecasters.

Here in Manhattan Central Park, a brief but intense event, with perhaps 0.75 inches of snow deposited in a half hour.

Winds probably around 30 mph at peak.

Think it was called very accurately by the various observers here.

3 minutes ago, weatherpruf said:

That's fine, but I get concerned that we are heading into a permanent state like this at some point, and that will not be a good thing, because it will mean a lot of other bad things are going on as well.

For New Yorkers, coming off several years of good snows, a slow winter such as what we appear to be having would be more normal than another above average precipitation season.

Only if it stays slow for the next five years would I'd start to be concerned. 

Can't blame the model, it just does what it is told.

This should however serve as a cautionary example, to keep people from getting too enamored with some specific model run.

Imho, longer range forecasting is still embryonic at best. The skill levels must be embarrassing, but that is ok, we start from a low base.

The main concern is that there does not seem to be a clear strategy for improvement other than to get more computer power to allow tighter model grids.

Given the erratic performance of the tight grid IBM model, (Deep Thunder, I believe it is called) perhaps that is too optimistic a view.

Possibly the models will need to have still better integrated physics, not a quick fix at all.

7 minutes ago, purduewx80 said:

Yes, the FV3 is the new version of the GFS; the pivotalwx link is for the current operational version. They are entirely different models.

Thank you for putting this right.

The older Pivotal Weather modeling only showed large negative numbers for the anomalies, so if the newer model verifies, we are looking at 40*F negative anomalies in late January. Impressive!

3 hours ago, purduewx80 said:

It literally says 2m temperatures on the top. Ridging from the North Pole to just N of Alaska through the extended period has already and will continue to deliver frigid air into North America. Widespread -30s in place over the NW Territories this morning. 

It shows much warmer for 12Z on Jan 28th on Pivotal Weather here:

http://www.pivotalweather.com/model.php?m=gfs&p=sfct&rh=2019011312&fh=360&r=conus&dpdt=&mc=

Is this a model difference issue or am I missing something important?

6 minutes ago, Snow88 said:

Euro is similair

18 minutes ago, NYCweatherNOW said:

I’ve never seen a model output such as this mornings para GFS showing cold temps like this. This would be insane after a devastating ice storm 

Believe this show temperatures anomalies rather than temperatures.  Still seriously chilly though. 

The improvements remain modest, at least if the precipitation estimates over the 10 day horizon are the criterion. The stability of the forecast falls very rapidly after day three.

Apart from the warmer than usual water around Greenland, is there any evidence that this kind of post ice age event is possible during inter glacial periods such as the one we are now in?

7 minutes ago, gravitylover said:

Yay I'm home! Doesn't it figure as we come up the hill it starts sorta snowing and by the time we got to the house it was an all out graupel fest. It made for an interesting hobble up the hill from the street.  Boy it feels good to be home...

Delighted to hear that!!

Take good care of yourself, this place needs you.

55 minutes ago, ChescoPaWxman said:

JB with Weatherbell saying all the players are now on the field that may lead to one of the all-time greatest comeback winters.....now whether that is reality or not.....like I said stay tuned

JB swings for the fences, unlike most of his peers. That is why he has a devoted following.

Admittedly,  he has to eat crow more frequently than some as a result, but he clearly sees it as a reasonable tradeoff.

Thank you, donsutherland1 for this excellent outlook summary. It is the best winter status/expectations report for our area that I've seen.