December pattern/forecast thread

[Ginx snewx]

4 minutes ago, OceanStWx said:

Yeah looks like a 6" mean NW of 91, N of 90, and NW of 495. A 12" mean is more like N of Route 2 and NW of the Lakes Regions in NH and ME.

ORH

[OceanStWx]

If you look at the individual members over the next 15 days, the picture is about what we've been preaching. We'll have chances but there is a little bit of playing with fire.

Around 17 or 18 members are probably what'd we'd all consider to be whiffs for SNE (only a couple inches at best). A 33% whiff to 66% success seems fair at this point. Of course there are a couple of whoppers in there, but we're talking less than 10% of the members. 

And member 13 would have powderfreak pushing 3 new feet of snow by Christmas week.

[512high]

6 minutes ago, OceanStWx said:

If you look at the individual members over the next 15 days, the picture is about what we've been preaching. We'll have chances but there is a little bit of playing with fire.

Around 17 or 18 members are probably what'd we'd all consider to be whiffs for SNE (only a couple inches at best). A 33% whiff to 66% success seems fair at this point. Of course there are a couple of whoppers in there, but we're talking less than 10% of the members. 

And member 13 would have powderfreak pushing 3 new feet of snow by Christmas week.

Is it fair to say that "maybe" in 5-7 days, we would have a greater feel, if we could lock in a large event that the members would agree on?

[OSUmetstud]

8 minutes ago, OceanStWx said:

If you look at the individual members over the next 15 days, the picture is about what we've been preaching. We'll have chances but there is a little bit of playing with fire.

Around 17 or 18 members are probably what'd we'd all consider to be whiffs for SNE (only a couple inches at best). A 33% whiff to 66% success seems fair at this point. Of course there are a couple of whoppers in there, but we're talking less than 10% of the members. 

And member 13 would have powderfreak pushing 3 new feet of snow by Christmas week.

How are accurate is the EPS mean precip/snow product?  Is there any literature on it's usefulness?  It seems like it's fun weeny stuff.  

[Ginx snewx]

1 minute ago, OSUmetstud said:

How are accurate is the EPS mean precip/snow product?  Is there any literature on it's usefulness?  It seems like it's fun weeny stuff.  

Its a tool like any other. 

[OceanStWx]

2 minutes ago, 512high said:

Is it fair to say that "maybe" in 5-7 days, we would have a greater feel, if we could lock in a large event that the members would agree on?

I mean Monday could still work out as a bigger QPF event. But there is a risk of warmth aloft with how it all develops. 

But my post was more meant to convey how when Scott or Will says we will have chances, this is kind of what they mean. You run a model 50 times and maybe 30 hit, while the rest find ways to avoid the goods.

[512high]

Just now, OceanStWx said:

I mean Monday could still work out as a bigger QPF event. But there is a risk of warmth aloft with how it all develops. 

But my post was more meant to convey how when Scott or Will says we will have chances, this is kind of what they mean. You run a model 50 times and maybe 30 hit, while the rest find ways to avoid the goods.

Understood! Thanks for explaining ....

[OceanStWx]

2 minutes ago, OSUmetstud said:

How are accurate is the EPS mean precip/snow product?  Is there any literature on it's usefulness?  It seems like it's fun weeny stuff.  

My guess would be along the lines of most QPF related products, poor verification.

But more so than the GEFS, I think the EPS can illustrate a range of outcomes for a pattern. What I see in the means is a lot like how we've been describing the outlook. Chances, best being in and up, and we play with fire a bit.

[Ginx snewx]

Just now, OceanStWx said:

I mean Monday could still work out as a bigger QPF event. But there is a risk of warmth aloft with how it all develops. 

But my post was more meant to convey how when Scott or Will says we will have chances, this is kind of what they mean. You run a model 50 times and maybe 30 hit, while the rest find ways to avoid the goods.

GEFS Ens is like Jerry described, like you said chances. I am not buying the cold and dry over the next 15 days. QPF numbers are not dry on ENS, now who gets what, that is a different story

[HoarfrostHubb]

A nickel here...a nickel there...

seems like a fairly typical mid December.  

[Dsnowx53]

40 minutes ago, CoastalWx said:

Interesting comparison I did from the H5 anomalies at hr 360 from the 12/1/16 12z run to the current 12/6/16 12z run. The biggest trend I see is the Bering Sea ridge and west coast iof NAMR have much higher heights than the runs 5 days ago. Probably goes along with the models rushing to break down patterns. The NAO was also estimated too low from 5 days ago, so that continues to be voodoo on models. For the time being, the AO and NAO will hover near and above the neutral values it seems. But the Pacific will drive the bus as usual.

 

This is a great post. I've found that medium range models tend to underestimate PAC wave breaking events and their effects downstream and thus break those patterns down too quickly. But of course, they also are -NAO and -AO happy, as well. 

[OceanStWx]

2 minutes ago, Ginx snewx said:

GEFS Ens is like Jerry described, like you said chances. I am not buying the cold and dry over the next 15 days. QPF numbers are not dry on ENS, now who gets what, that is a different story

I think the Euro op shows how the pattern could miss and keep us cold and dry. We just get a series of trof passages that develop too late for much fanfare. But the op also has pretty deep trofing into the Southeast. The EPS keeps a mean SE ridge around, which would obviously help keep the storms in our vicinity.

[weathafella]

SV typically isn't that weenieish and it's definitely got 10+ to below the pike for a 15 day mean.  

[ORH_wxman]

7 minutes ago, weathafella said:

SV typically isn't that weenieish and it's definitely got 10+ to below the pike for a 15 day mean.  

Prob different algorithms for snowfall is creating the difference.

[powderfreak]

Just saw that EURO run... lol man what a weenie run.

Just snow every day or every other day.

What a start to the season if that's anywhere close to correct.  Not big snows but just consistent stuff that adds up over time.

[Ginx snewx]

3 minutes ago, powderfreak said:

Just saw that EURO run... lol man what a weenie run.

Just snow every day or every other day.

What a start to the season if that's anywhere close to correct.  Not big snows but just consistent stuff that adds up over time.

no doubt you are golden now

[CoastalWx]

Time to cool off those SSTs with 498 thicknesses.

[OSUmetstud]

1 hour ago, Ginx snewx said:

Its a tool like any other. 

Sure.  But some tools are more valuable than others.  The euro and the dgex are both tools.  

[ORH_wxman]

Just now, CoastalWx said:

Time to cool off those SSTs with 498 thicknesses.

The ensembles have really cold stuff for that far out too...wouldn't be shocked if we snuck a record or two in there when it verifies given that those days are kind of vulnerable too in some of the climate records.

[Damage In Tolland]

12 minutes ago, ORH_wxman said:

The ensembles have really cold stuff for that far out too...wouldn't be shocked if we snuck a record or two in there when it verifies given that those days are kind of vulnerable too in some of the climate records.

With snowcover should be no doubt about records 

[Typhoon Tip]

Eh Will  ... good call on the warning radar on the door-step...

p-type algorithms flashing N pa/S ny over to what's got to be baseball aggregates.

btw folks, i'm temped to start a thread/analysis outlook for Monday.  I'm pretty reasonably confident (for this sort of time range) of no purely water form event that day.  Could be a 4-6 hour quick ordeal, but tamps down a solid advisory thing. 

The pattern is also ripe for that sort of short window event.  I've been arguing against the bigger hitters for over a week because of the SE ridge and in fact, the heights over N/A (across the conus) are just hugely crushed with too much gradient to really allow S/W to mechanize the flow. but again, the short duration turn-overs get nods for me in this regime.

that one has been signaled by the GFS/GEFs for days too, pretty much in it's present modeled form.  the consistency in the oper. is pretty damn sweet for D5, more so than normal. These observations give that a good feel to me. I'm thinking that's got a better than average chance (relative to D5 ) for better synoptic event. ...not major, just performance-wise. Though ptype stuff is a concern ...there's no way to know for now.  i have a hunch though that neither side of the baroclinic wall is going to fade and that's probably what the GFS is locking into with that much consistency.  i bet it snows/mix ahead of a triple point that scoots out S of the region with and end as drizzle/freezing drizzle, just before the deepest cold shot of the season arrives.

man, there's serious witch blood up in Can btw.  one thing, the GGEM/Canad.  10-temp anomalies plummeted over the last three days ... now pressing -6 over southern Mantoba, and the whole continent is at least modestly negative now.  that's not something I've seen in recent Decembers, particularly this early, and i've been using that product for 15 years.  -6(.4) is a standard deviation nearing -2.5 with is impressive for a proper winter month anyway.  that some serious jack actually...  and f.u. : this product is one of the best things that comes out out of next door.

[powderfreak]

The 18z GFS continued the theme of winter.

They don't have MVL data but here's 1V4 at 700t in the Northeast Kingdom.

This is days and days of snow, but light amounts averaging 1" per day.  This is winter.    There was no rain out through 16 days. 

 

Same 18z GFS run.... Need more of this.

 

[USCAPEWEATHERAF]

I think we will get snow towards the third week of December and onward here on the coastal plain.  There is no doubt in my mind that we will get one good storm before Christmas week as that arctic airmass invades the Gulf Stream North Wall nearing 40N latitude.  Remember the explosive cyclogenesis that occurred on the morning of February 15th 2015, I think a storm like that will occur before Christmas week.

[ORH_wxman]

2 minutes ago, USCAPEWEATHERAF said:

I think we will get snow towards the third week of December and onward here on the coastal plain.  There is no doubt in my mind that we will get one good storm before Christmas week as that arctic airmass invades the Gulf Stream North Wall nearing 40N latitude.  Remember the explosive cyclogenesis that occurred on the morning of February 15th 2015, I think a storm like that will occur before Christmas week.

Highly doubtful we get a PV lobe to get south of our latitude like we saw in Feb 2015 with the SE ridge still present. We need a much more robust PNA ridge out west for that OR a huge NAO block. Neither are in the cards. 

Most of our threats are going to be overrunning/SWFE or clipper/redeveloper types. 

[USCAPEWEATHERAF]

Oh yeah, it was really a cold winter that year.  I meant a miller B storm event that will do what that event did.

[snywx]

40 minutes ago, ORH_wxman said:

Highly doubtful we get a PV lobe to get south of our latitude like we saw in Feb 2015 with the SE ridge still present. We need a much more robust PNA ridge out west for that OR a huge NAO block. Neither are in the cards. 

Most of our threats are going to be overrunning/SWFE or clipper/redeveloper types. 

Sign me up! Thats a beautiful thing for those in interior SNE & E NY.

[dryslot]

I think most would approve that 0z GFS run on monday, Looks to get a secondary going over SNE and plenty cold to boot for snow inland away from the coast

[USCAPEWEATHERAF]

Yeah I would kill for the system next week to become all snow.  Anyways, it looks like many snow chances exists as the polar jet becomes quite active once again with a +PNA regime trying to build eastward over the western US.

[MJO812]

19 minutes ago, dryslot said:

I think most would approve that 0z GFS run on monday, Looks to get a secondary going over SNE and plenty cold to boot for snow inland away from the coast

Low went further south compared to 18z

CMC is very weak compared to the GFS

[Damage In Tolland]

Sunday night/Monday looking mighty interesting. Modeling with advisory snows for most places. Even the coast would snow to start