Potential for big event looms large March 28-30

[earthlight]

Not to be a Debbie downer, but it's still 5 days out and the 18z GFS, and it's early April, with the 850 zero line running about 80 miles north of NYC.

The 850 0c line doesn't get north of the South Shore

[Edge Weather]

Well, the NOGAPS site is down now for the 18z run.

Highly unlikely solution...but where is atownwxwatcher with the NOGAPS? That should tell us for sure if this storm is possible.

[Diego]

That's not the 850 line. That's the surface line. And right after that it drops below for NYC as well.

I know. I didn't post the link above to the 850, which is below.

http://mag.ncep.noaa.gov/NCOMAGWEB/appcontroller?prevpage=Param&MainPage=indexℑ=&page=Param&cycle=03%2F27%2F2011+18UTC&rname=UPPER+AIR+PARMS&pname=850_temp_ht&model=GFS&area=NAMER&cat=MODEL+GUIDANCE&areaDesc=North+America+-+US%2C+Canada%2C+and+northern+Mexico&fcast=03%2F27%2F2011+18UTC+126HR

[earthlight]

I know. I didn't post the link above to the 850, which is below.

It doesn't get north of NYC at all, and the 850 low and other mid level centers are closed off in a nearly classic spot..this is a snowstorm for most posters in this forum.

Is it correct? Most likely not.

[Diego]

The 850 0c line doesn't get north of the South Shore

But you're correct in its placement.

[CooL]

looks like the ens mean surface low track is right over the benchmark, 996mb..But when does the mean not agree with the op?

[Edge Weather]

The mean has NOT agreed with the operational on almost all the prior runs. The operational has gone the way now of agreeing with the mean for the first time. The mean has shown this solution for several runs now, and by the way the EC mean shows the same thing almost exactly.

looks like the ens mean surface low track is right over the benchmark, 996mb..But when does the mean not agree with the op?

[Diego]

It doesn't get north of NYC at all, and the 850 low and other mid level centers are closed off in a nearly classic spot..this is a snowstorm for most posters in this forum.

Is it correct? Most likely not.

But even assuming its correct, I disagree that most posters would view this as a snowstorm given the time of year, the marginal surface temps. and temps. at 850. And you have to factor in the sun angle if a daylight occurence. But would there would probably be at least some snow on the front and or back end.

[NEG NAO]

http://raleighwx.americanwx.com/models/gfs/18zgfssnow138.gif

result is similar to 4/6/82 - so it can happen

[ag3]

But even assuming its correct, I disagree that most posters would view this as a snowstorm given the time of year, the marginal surface temps. and temps. at 850. And you have to factor in the sun angle if a daylight occurence. But would there would probably be at least some snow on the front and or back end.

850 low placement and closed H5 south of us, with 1.50" of heavy Qpf, is a sure way to get snow, this time of year.

[Diego]

850 low placement and closed H5 south of us, with 1.50" of heavy Qpf, is a sure way to get snow, this time of year.

But despite the QFP, you also need a stronger source of arctic air at this time of year than the one the models are depicting to be gradually eroding and receding to the east in Quebec away from us. Higher elevations to the north and west could get zonked and we certainly could get some wet snow here under that set up, but not a major snowstorm imho.

[Edge Weather]

I don't know who you are, but let me tell you that earthlight knows what he is talking about. He is one of the most knowledgeable weather people we have in this forum.

But even assuming its correct, I disagree that most posters would view this as a snowstorm given the time of year, the marginal surface temps. and temps. at 850. And you have to factor in the sun angle if a daylight occurence. But would there would probably be at least some snow on the front and or back end.

[NEG NAO]

I don't know who you are, but let me tell you that earthlight knows what he is talking about. He is one of the most knowledgeable weather people we have in this forum.

and didn't he say its highly unlikely ? show this run a few runs in a row and have the EURO come on board with a cold solution then we can talk snow

[Diego]

I don't know who you are, but let me tell you that earthlight knows what he is talking about. He is one of the most knowledgeable weather people we have in this forum.

And I agree and have the utmost respect for him, but I'm entitled to disagree.

[ag3]

Diego,

We aren't saying that it will snow a lot on Friday but the depiction of the GFS is most certainly a heavy snowfall, even in city.

But it's most likely wrong.

Let's hope it's not.

But IMHO,

We will see snow from 1 of the 2 systems. Either the euro Wednesday storm or the bigger Friday night storm.

[ag3]

and didn't he say its highly unlikely ? show this run a few runs in a row and have the EURO come on board with a cold solution then we can talk snow

Euro has had a big storm solution for several runs in a row before today's 12z.

Todays run focused on a much bigger Wednesday storm instead and as Coastalwx explained, that caused the barolonic zone to shift east into ocean and thus the Friday storm showed out to sea.

[Diego]

and didn't he say its highly unlikely ? show this run a few runs in a row and have the EURO come on board with a cold solution then we can talk snow

But the issue here was what would happen if the above depiction was true. No one's in disagreement about it's unlikeliness.

[earthlight]

But even assuming its correct, I disagree that most posters would view this as a snowstorm given the time of year, the marginal surface temps. and temps. at 850. And you have to factor in the sun angle if a daylight occurence. But would there would probably be at least some snow on the front and or back end.

Not sure I am understanding your point..are you saying that the GFS verbatim wouldn't be a snowstorm? By most people I mean those away from the beaches and eastern Long Island.

[NEG NAO]

But the issue here was what would happen if the above depiction was true. No one's in disagreement about it's unlikeliness.

seriously you have to consider this solution is a possibility because of the extreme weather we have had the last few years and especially this winter.......

[earthlight]

seriously you have to consider this solution is a possibility because of the extreme weather we have had the last few years and this winter.......

Pretty weak argument

[Diego]

Diego,

We aren't saying that it will snow a lot on Friday but the depiction of the GFS is most certainly a heavy snowfall, even in city.

But it's most likely wrong.

Let's hope it's not.

But IMHO,

We will see snow from 1 of the 2 systems. Either the euro Wednesday storm or the bigger Friday night storm.

Ok, but I disagree with that depiction with respect to the city.

[earthlight]

Ok, but I disagree with that depiction with respect to the city.

I'm not sure how you can, unless you're arguing that the snow would melt. That's completely possible, but you have to figure that with over an inch of liquid QPF falling, heavy frontogenic forcing to the northwest of the closed mid level centers, and strong dynamics with the strengthening low pressure and h5 shortwave...that the snow would be falling hard enough to stick.

Luckily, with todays technology we have maps which can take into account ground and soil temperature as well as snow rate and melting..and even they show a 6" snowfall in the city which seems reasonable.

Again, this is taking the 18z GFS verbatim, which if you ask me is most likely wrong.

[NEG NAO]

Pretty weak argument

ok I will ad to the argument that the EURO had a similar solution at one point and when that happens the chances imcrease same thing happened before the 2010 Boxing Day storm

[earthlight]

By the way, I am not advertising the accuracy of those maps..but I find them to be the most reasonable of the snow depth maps at this range. The earl barker ones and the storm vista ones are just rain/snow and liquid algorithms

[NEG NAO]

By the way, I am not advertising the accuracy of those maps..but I find them to be the most reasonable of the snow depth maps at this range. The earl barker ones and the storm vista ones are just rain/snow and liquid algorithms

IF that were to verify a few places in NYC metro would be challenging the 95 - 96 seasonal records

[Edge Weather]

Can you provide a link to those maps?

By the way, I am not advertising the accuracy of those maps..but I find them to be the most reasonable of the snow depth maps at this range. The earl barker ones and the storm vista ones are just rain/snow and liquid algorithms

[Diego]

I'm not sure how you can, unless you're arguing that the snow would melt. That's completely possible, but you have to figure that with over an inch of liquid QPF falling, heavy frontogenic forcing to the northwest of the closed mid level centers, and strong dynamics with the strengthening low pressure and h5 shortwave...that the snow would be falling hard enough to stick.

Luckily, with todays technology we have maps which can take into account ground and soil temperature as well as snow rate and melting..and even they show a 6" snowfall in the city which seems reasonable.

Again, this is taking the 18z GFS verbatim, which if you ask me is most likely wrong.

I acknowledge that the dynamics are all there. But you can't disregard the time of the year, and I would also add in climo. Besides the weakening and receding souce of arctic air, consider the snowfall statistics for Central Park over the past 140 years. During that period, there were only 4 instances when there were major snowstorms here, 1875, 1915, 1917 and 1982. Yet, I'll bet there were numerous setups similar to what the 18Z GFS has been depicting, where at best, we received maybe a mixture to several inches of wet snow because of borderline surface to 850 temps. and the sun angle. If this were merely forecasted to have occurred 2 weeks ago, we would get zonked,

[IsentropicLift]

Maybe I am wrong, but I remember the NAM being pretty good with the last storm, better than the GFS, even at 84 hrs. In fact, I remember the 84 hr NAM being better than the GFS on many occasions this winter.

With the last event the NAM showed us getting crushed before finally backing off at 18z. Either way my comment wasn't meant to be nasty. This storm looks like the real deal.

[ag3]

I acknowledge that the dynamics are all there. But you can't disregard the time of the year, and I would also add in climo. Besides the weakening and receding souce of arctic air, consider the snowfall statistics for Central Park over the past 140 years. During that period, there were only 4 instances when there were major snowstorms here, 1875, 1915, 1917 and 1982. Yet, I'll bet there were numerous setups similar to what the 18Z GFS has been depicting, where at best, we received maybe at best a mixture to several inches of wet snow because of borderline surface to 850 temps. and the sun angle. If this were merely forecasted to have occurred 2 weeks ago, we would get zonked,

Just want to add that both the storms are progged for Wednesday night and Friday night. So no sun angle as a factor.

[CooL]

I acknowledge that the dynamics are all there. But you can't disregard the time of the year, and I would also add in climo. Besides the weakening and receding souce of arctic air, consider the snowfall statistics for Central Park over the past 140 years. During that period, there were only 3 instances when there were major snowstorms here, 1875, 1915, 1917 and 1982. Yet, I'll bet there were numerous setups similar to what the 18Z GFS has been depicting, where at best, we received maybe at best a mixture to several inches of wet snow because of borderline surface to 850 temps. and the sun angle. If this were merely forecasted to have occurred 2 weeks ago, we would get zonked,

who is desregarding the time of year? earthlight?! he just said its highly unlikely

enough stating the obvious, we know its april, sun angle and what not ect. We are all hardcore. Earthlight just showed you up that what the 18z gfs has verbatim would be a snowstorm for nyc metro.