00z Dec 8 Model Guidance

[Absolute Humidity]

Kinda makes me appreciate just how difficult it is to get all these features inplace for snow to actually occur. Its like the hopeless romantic chasing the love he never can get.

[Chris L]

Kinda makes me appreciate just how difficult it is to get all these features inplace for snow to actually occur. Its like the hopeless romantic chasing the love he never can get.

Good analog....

And when the pieces do fall together, its pretty sweet, isn't it?

[SnowGoose69]

Kinda makes me appreciate just how difficult it is to get all these features inplace for snow to actually occur. Its like the hopeless romantic chasing the love he never can get.

In the right winter its so easy, in the bad winters it seems so hard...last year on 12/19 when we got 2 inches in one hour I thought to myself..."how was it so hard to get this much in 4 whole months in 01-02 or 97-98?" its amazing how it comes so easy some years and not at all others.

[SnoSki14]

Kinda makes me appreciate just how difficult it is to get all these features inplace for snow to actually occur. Its like the hopeless romantic chasing the love he never can get.

And yet there are years like last year where getting snow is as easy as 2+2. It's mostly the state of the ENSO that's creating havoc, had the la nina been a bit weaker, we could have had a stronger PNA, the blocking would have stayed in place more, and a stronger subtropical jet could have made miller A's more possible.

[winterwx21]

Cold/dry, a warm storm and then back to cold/dry. Frustrating pattern. For those that feel that December is the best chance of seeing significant amounts of snow in this La Nina winter, this sure is off to a lousy start. Hopefully we'll see something in the 2nd half of December, but the 1st half of the month is turning out to be a read dud.

[tombo82685]

a 1052 high in central canada at hr 264, with a storm cutting acorss the middle of the country

[Chris L]

Cold/dry, a warm storm and then back to cold/dry. Frustrating pattern. For those that feel that December is the best chance of seeing significant amounts of snow in this La Nina winter, this sure is off to a lousy start. Hopefully we'll see something in the 2nd half of December, but the 1st half of the month is turning out to be a read dud.

Well if we go by climatology, we do not get that much snow in early December.

[Absolute Humidity]

Good analog....

And when the pieces do fall together, its pretty sweet, isn't it?

Oh yeah

[Isotherm]

Cold/dry, a warm storm and then back to cold/dry. Frustrating pattern. For those that feel that December is the best chance of seeing significant amounts of snow in this La Nina winter, this sure is off to a lousy start. Hopefully we'll see something in the 2nd half of December, but the 1st half of the month is turning out to be a read dud.

Well let's remember that this is not a snowy time of year anyway. If we don't get any snow in the Dec 15th-30th period, then I'd worry. From a statistical standpoint, the majority of winters that featured > 3" of snow in NYC by New Years were average or above avg snowfall winters.

I think the blocking will be more efficient after this storm, w/ a stronger -AO and more west based -NAO. If we've got that in place, then short waves can dig under the block and acquire a neg tilt upon reaching the east coast, not the OH valley.

[Chris L]

Well let's remember that this is not a snowy time of year anyway. If we don't get any snow in the Dec 15th-30th period, then I'd worry. From a statistical standpoint, the majority of winters that featured > 3" of snow in NYC by New Years were average or above avg snowfall winters.

I think the blocking will be more efficient after this storm, w/ a stronger -AO and more west based -NAO. If we've got that in place, then short waves can dig under the block and acquire a neg tilt upon reaching the east coast, not the OH valley.

Let's not forget the MJO driver, its not in the best spot for east coast snowstorms.

Any odds when that will change?

[tombo82685]

Question, with all this blocking in canada, and the high hgts can that still produce cold air? The gfs has 522 thickness's in north central canada, up there thats pretty warm, does that equate to a warmer airmass? Or since its just dominated by high pressure being over the snow pack the airmass has no change?

[jrodd321]

Trainwreck this run in the long term.

[tombo82685]

Let's not forget the MJO driver, its not in the best spot for east coast snowstorms.

Any odds when that will change?

this is nceps forecast, it looks like its heading toward zone 7 then falls back in the circle of death. I asked this is the 18z forum, what does the circle of death mean? Does it mean the mjo has a less driving force on the pattern?

[SnoSki14]

Well let's remember that this is not a snowy time of year anyway. If we don't get any snow in the Dec 15th-30th period, then I'd worry. From a statistical standpoint, the majority of winters that featured > 3" of snow in NYC by New Years were average or above avg snowfall winters.

I think the blocking will be more efficient after this storm, w/ a stronger -AO and more west based -NAO. If we've got that in place, then short waves can dig under the block and acquire a neg tilt upon reaching the east coast, not the OH valley.

Nope, another cutter at 288-300 hours on the gfs. Not that it makes a difference what happens nearly 300 hours out, but it's amazingly that we still can't get any snow threat way out in the long range, just cold/dry to warm/rain.

[winterwx21]

We did have a few years recently where NYC got its first snowstorm in early December (usually around the 5th). But I know that's more the exception than the rule. You guys are right, but I was just making the point that December is supposed to be a favored month in La Nina winters. So it is a little disappointing that we're gonna get through mid month without anything. Hopefully the 2nd half of the month will be good. If it isn't, we're at great risk of seeing below normal snowfall this winter.

[isnice]

a 1052 high in central canada at hr 264, with a storm cutting acorss the middle of the country

Lol ends up being an exact repeat of what we're gong to have Sunday. Literally, exact repeat. This is comical...

[Isotherm]

Let's not forget the MJO driver, its not in the best spot for east coast snowstorms.

Any odds when that will change?

I'm not sure the MJO has been/will be much of a help in terms of forecasting this winter. It's been in phase 4 recently, and forecast to move into P5-6 which teleconnects to a warm CONUS and positive NAO. But obviously that has not been the case. We've gotten the -NAO/-AO and cold US without favorable MJO forcing. The position of the GOA low and the orientation of the NAO block are the big keys in this pattern IMO.

[mattinpa]

Lol ends up being an exact repeat of what we're gong to have Sunday. Literally, exact repeat. This is comical...

I really question that one. What a rotten run - it gets bitterly cold and still rains with storm #2! I think the blocking should be better for that one, and lots of runs to go.

[Chris L]

I'm not sure the MJO has been/will be much of a help in terms of forecasting this winter. It's been in phase 4 recently, and forecast to move into P5-6 which teleconnects to a warm CONUS and positive NAO. But obviously that has not been the case. We've gotten the -NAO/-AO and cold US without favorable MJO forcing. The position of the GOA low and the orientation of the NAO block are the big keys in this pattern IMO.

Thanks for the clearing up.

Yes the lack of EPO ridge is hurting us.

If we just had that ridge, things would likely look better, but on the long range runs, that GOA low is not leaving its spot.

[SnoSki14]

I think a lot of people were expecting more than what's probably going to happen. I think many believed they could get a big snowstorm or two in December when the reality doesn't favor it. The blocking and -NAO is only helping by getting the month to end up colder than average, but it's not working with the disturbances and shortwaves to produce snow. The biggest culprit of cold does not equal snow is definitely the GOA low, and thus the lack of the +PNA. Even a weaker GOA low or neutral PNA would rapidly increase our chances.

[Isotherm]

Nope, another cutter at 288-300 hours on the gfs. Not that it makes a difference what happens nearly 300 hours out, but it's amazingly that we still can't get any snow threat way out in the long range, just cold/dry to warm/rain.

Honestly, model projections post D 8 have proven to be garbage. We've already seen the GFS depict a snowy pattern days 10-15 a few times in the past month, and obviously that has busted. So I don't really care what's being shown that far out.

[Absolute Humidity]

In the right winter its so easy, in the bad winters it seems so hard...last year on 12/19 when we got 2 inches in one hour I thought to myself..."how was it so hard to get this much in 4 whole months in 01-02 or 97-98?" its amazing how it comes so easy some years and not at all others.

Those were some frustrating years. And yes, when the Dec. 30th,s 2000 popup, they seem to come so natural, as if they were ment to happen all the time. But our reality is, they're not all that frequent.

[SnoSki14]

It is mind blowing when one moderate snowstorm 4-8", we can get just as much or close to the amount of snow in some of those off years. Just look at Baltimore or D.C. where they picked up over 20" with one storm. Many times it takes a 2-3 winters to produce that much snow that one storm has created.

[tombo82685]

here is the 0z ggem at hr 96, looks like its following the gfs and ukie, it actually looks a little further south than the gfs.

[tombo82685]

here is the hr 120 from the ggem, looks like an identical track from the gfs, primary to cincy, then a secondary a little further west than the gfs over central pa

[isnice]

I'll take my snow showers and run.

The long-range may look bleak for snow chances, but at least it's winter (meaning it's cold). I'm sure we'd all be much less happy to see Seattle getting pounded with snow while we were stuck with 50 degrees and rain all through december. I see another 2005-2006 season, where everything was horrid until that February storm. I'm feeling a blockbuster this winter, but the days leading up to it will either be cold and dry or warm and wet. That's La Nina for ya.

[nzucker]

Question, with all this blocking in canada, and the high hgts can that still produce cold air? The gfs has 522 thickness's in north central canada, up there thats pretty warm, does that equate to a warmer airmass? Or since its just dominated by high pressure being over the snow pack the airmass has no change?

There wouldn't be much arctic air in the pattern; as you say, the cold air is being cut off from Canada and you can see that the cross-polar flow is occurring from the PV in Siberia towards Europe. All of the models are showing the PV currently over Canada retreating rapidly next week with a serious blocking ridge setting up over most of Canada. There'd be some low level cold air underneath the strong high pressure, so it's not quite as warm as it looks at 850mb, but still not the real arctic stuff. I'd think a lot of the CONUS would stay below average in temperatures though due to the high pressing southward and the low-level cold. Here is a good shot of the cross-polar flow being cut from the 12z ECM:

I'm not sure the MJO has been/will be much of a help in terms of forecasting this winter. It's been in phase 4 recently, and forecast to move into P5-6 which teleconnects to a warm CONUS and positive NAO. But obviously that has not been the case. We've gotten the -NAO/-AO and cold US without favorable MJO forcing. The position of the GOA low and the orientation of the NAO block are the big keys in this pattern IMO.

Yes, but the current MJO state and general lack of tropical forcing is making it hard to get rid of the GoA low with the strong Niña firmly in control of the pattern. This means that most shortwaves are entering the country too far north over the Plains to benefit the I-95 corridor in terms of snowfall, which is one of the reasons for the cold/dry pattern with bare ground. So I do think the MJO is important in what signal it is sending to the North Pacific this December.

[isnice]

Lol- GFS ensembles don't event take it up the lakes. They bring the low to the southeast over North Carolina at hour 120, then a coastal hugger. Geez...

[isnice]

108

120

132

[Isotherm]

There wouldn't be much arctic air in the pattern; as you say, the cold air is being cut off from Canada and you can see that the cross-polar flow is occurring from the PV in Siberia towards Europe. All of the models are showing the PV currently over Canada retreating rapidly next week with a serious blocking ridge setting up over most of Canada. There'd be some low level cold air underneath the strong high pressure, so it's not quite as warm as it looks at 850mb, but still not the real arctic stuff. I'd think a lot of the CONUS would stay below average in temperatures though due to the high pressing southward and the low-level cold. Here is a good shot of the cross-polar flow being cut from the 12z ECM:

Yes, but the current MJO state and general lack of tropical forcing is making it hard to get rid of the GoA low with the strong Niña firmly in control of the pattern. This means that most shortwaves are entering the country too far north over the Plains to benefit the I-95 corridor in terms of snowfall, which is one of the reasons for the cold/dry pattern with bare ground. So I do think the MJO is important in what signal it is sending to the North Pacific this December.

Yes, the tropical forcing we have w/ the strong la nina basically guarantees the presence of a -PNA/GOA low to some extent. That's going to be a burden we'll deal w/ all winter most likely. But if the NAO orientation is in a favorable, west based position, it would cause short waves to dig further SE and produce snow for our area. A GOA low, although it discourages a southern stream, is not a complete disaster in terms of snow if we've got a good AO/NAO regime.