The PHL/NYC Medium Range Thread - Part 2

[earthlight]

February 2006 was a good example.

That's the ultimate "timing" event. Really was just a huge +PNA spike, coupled with a transient 50/50 block which happened to support the rapid amplification of the H5 trough at the perfect time. That setup was surrounded by an absolutely god-awful pattern.

[Dark Energy]

jesus. before i clicked the link i figured the greenland block would meet up with the block over the pacific. indeed it looks like it will or *may.

i think i saw some Euro maps that had the greenland block so far west that it set up a rex block as the trof over our area is trapped under it. this is why the gfs seems odd in that prev runs it tried to bring the trof from the next big storm too far north. the trof should set up shop over us just like the last closed gyre did not too long ago.

[earthlight]

Here's the pattern surrounding that epic event..a few days earlier, followed by a few days later, both awful.

http://www.meteo.psu.edu/~gadomski/NARR/2006/020221.png

http://www.meteo.psu.edu/~gadomski/NARR/2006/021621.png

[Chris L]

That's the ultimate "timing" event. Really was just a huge +PNA spike, coupled with a transient 50/50 block which happened to support the rapid amplification of the H5 trough at the perfect time. That setup was surrounded by an absolutely god-awful pattern.

Indeed and 22 inches later....

But goes to show you we can get something in timing.

We are in MUCH better shape with the NAO situation right now; though.

[Dark Energy]

That's the ultimate "timing" event. Really was just a huge +PNA spike, coupled with a transient 50/50 block which happened to support the rapid amplification of the H5 trough at the perfect time. That setup was surrounded by an absolutely god-awful pattern.

yea, have you noticed that the only ridging out west is being shown over the SW states? there is no ridge spiking north of there.

[earthlight]

i think i saw some Euro maps that had the greenland block so far west that it set up a rex block as the trof over our area is trapped under it. this is why the gfs seems odd in that prev runs it tried to bring the trof from the next big storm too far north. the trof should set up shop over us just like the last closed gyre did not too long ago.

The Euro has been indicative of this -NAO for a week or two now. If this does come to fruition we have to give tons of credit to it's weeklies from a few weeks ago which had this -NAO that went west based with huge height departures.

Regarding the ULL...I think if the west based NAO does develop, it's going to lift north and be forced to elongate more west to east (favorable confluent flow to our north), as opposed to the last one, which escaped north as the NAO collapsed.

[earthlight]

yea, have you noticed that the only ridging out west is being shown over the SW states? there is no ridge spiking north of there.

Yup, the Pacific jet is just eating away at anything that tries to build..and it will continue to do so until we can get a more favorable Pacific pattern across the board. Probably won't be anytime soon, either, so we will have to make due without it. We have had some biggies without a big PNA ridge, though, so that's not to say it can't happen.

[Dark Energy]

Yup, the Pacific jet is just eating away at anything that tries to build..and it will continue to do so until we can get a more favorable Pacific pattern across the board. Probably won't be anytime soon, either, so we will have to make due without it. We have had some biggies without a big PNA ridge, though, so that's not to say it can't happen.

i don't like our chances without the +pna. just saying. yea, it has happened, but it is much easier for the s/w trofs to dive on the east side of the ridge.

[SnowGoose69]

i don't like our chances without the +pna. just saying. yea, it has happened, but it is much easier for the s/w trofs to dive on the east side of the ridge.

-PNA/-NAO can be very good but that -NAO had better be in the right place.

[Dark Energy]

The Euro has been indicative of this -NAO for a week or two now. If this does come to fruition we have to give tons of credit to it's weeklies from a few weeks ago which had this -NAO that went west based with huge height departures.

Regarding the ULL...I think if the west based NAO does develop, it's going to lift north and be forced to elongate more west to east (favorable confluent flow to our north), as opposed to the last one, which escaped north as the NAO collapsed.

yea, that ULL moved north, but hell, it was over the NE for what, 4-5 days or something?

[Dark Energy]

-PNA/-NAO can be very good but that -NAO had better be in the right place.

I see your point on that. But dont you think we have a better chance historically with +pna/-nao? i mean, i know the PAC is killing the +pna right now, and we may have to take what we can. I like it more cut and dry. easier for the models to latch onto something that is real.

[Dark Energy]

right now, im pretty much keeping the -nao as a given until it shows any signs that it will quit. just need the pna to cooperate. in the meantime, we are all looking at these long range models for something that just is either bs or a tease.

[nzucker]

If this becomes the seasonal trend,which so far it seems like its heading that way, then I think we'll get ours as soon (if?) as the pacific cooperates

I'm really hoping we can get a clipper to amplify down the PNA ridge that the models seem to show around Day 7/8; that looks to be the next significant s/w for the NYC metro area to watch. Here's what the 18z GFS shows, a permutation of a similar idea of a PNA spike towards neutral/a bit positive. Unfortunately, this run doesn't develop the western ridge completely so the shortwave ejects very flat and eventually minors out, but it's a decent set-up with a confluent 50/50 low as well as a 1064mb arctic high sitting in Canada:

I;m interested in DT's info that the la nina is weakening. If that trend continues, whoa. We all may be in for a surprise.

It has been strengthening a lot at the surface recently despite the warming in subsurface anomalies that took place around mid-November. Here is a comparison of Pacific SSTs from now, 3 days ago, and a week ago.

Current:

3 Days Ago:

Week Ago:

You can really see a cold pool expanding around 140W as well as major cooling in the eastern regions with colder waters all the way from Region 3 to Central America. Still under heavy trade winds too with the SOI averaging around +25 to +30 lately.

If that trend continues, get ready for an historic winter for both snow and cold, and I'm not exaggerating.

Meh...the damage has already been done in terms of the Pacific. It's way too late in the winter for a reversal to more Niño-like patterns of tropical forcing. We have a Niña that is in the low-end strong category in early December and still building.

[SnowGoose69]

right now, im pretty much keeping the -nao as a given until it shows any signs that it will quit. just need the pna to cooperate. in the meantime, we are all looking at these long range models for something that just is either bs or a tease.

When you look back at the NAO indices to 1950 there are surprisingly a decent number of years where a negative NAO in Nov/Dec was positive for both the ensuing Jan/Feb....00-01 and 02-03 are two cases where that occurred...more frequently though it seems the NAO goes positive for January and then negative again for February....the other interesting thing to note is that in the cases where a negative Nov/Dec NAO went positive for both Jan and Feb...2002-2003 is the only year where the October NAO was also negative...every other case the October NAO was positive.

[uncle W]

1954-55 had a negative nao Jan-March with little snow to show for it...AO was negative most of the time...No matter how cold that winter got most of the time it warmed up and rained...The weak storms gave us most of the snowfall we saw that season...

[Isotherm]

right now, im pretty much keeping the -nao as a given until it shows any signs that it will quit. just need the pna to cooperate. in the meantime, we are all looking at these long range models for something that just is either bs or a tease.

Well considering 9/11 moderate/strong La Nina's featured a -PNA, it's very difficult historically speaking to sustain a +PNA pattern w/ this ENSO state.

While it is true that our snowiest winters come with a +PNA/-NAO couplet, it's also true that we've seen many cold winters with near normal snowfall in a -PNA/-NAO state.

As John posted, we could have a nice gradient pattern setting up in the medium to long range w/ short waves eecting ewd from the PAC NW and propagating across the country.

PNA looks to be approaching neutral as the Arctic/Atlantic signalling improves D8-10+

[Dark Energy]

Well considering 9/11 moderate/strong La Nina's featured a -PNA, it's very difficult historically speaking to sustain a +PNA pattern w/ this ENSO state.

While it is true that our snowiest winters come with a +PNA/-NAO couplet, it's also true that we've seen many cold winters with near normal snowfall in a -PNA/-NAO state.

As John posted, we could have a nice gradient pattern setting up in the medium to long range w/ short waves eecting ewd from the PAC NW and propagating across the country.

PNA looks to be approaching neutral as the Arctic/Atlantic signalling improves D8-10+

I agree, Tom, that -pna/-nao can still pop something. But is it usually of substance? I'm sure there have been good storms in that setup. I really only favor storms over a foot of snow. Anything else is not high in my book. I guess i like svr wx more in a way, but a big snowstorm is cool too. But it has to be a good storm for me to get excited about it. and those usually happen more, imo, in the +pna/west -nao regime. But to each his own.

[Chris L]

I agree, Tom, that -pna/-nao can still pop something. But is it usually of substance? I'm sure there have been good storms in that setup. I really only favor storms over a foot of snow. Anything else is not high in my book. I guess i like svr wx more in a way, but a big snowstorm is cool too. But it has to be a good storm for me to get excited about it. and those usually happen more, imo, in the +pna/west -nao regime. But to each his own.

I believe the February 1969 snowstorms occured when the -NAO and it had a -PNA.

Still the Lindsay storm put 20+ over the NYC area.

[earthlight]

Tonight's 00z GFS has a pretty classic -NAO block...and the vortex in SE canada also allows for some interesting possibilities.

[Isotherm]

I agree, Tom, that -pna/-nao can still pop something. But is it usually of substance? I'm sure there have been good storms in that setup. I really only favor storms over a foot of snow. Anything else is not high in my book. I guess i like svr wx more in a way, but a big snowstorm is cool too. But it has to be a good storm for me to get excited about it. and those usually happen more, imo, in the +pna/west -nao regime. But to each his own.

Yeah I agree w/ you on that, most of the storms are under 12" in magnitude. I guess that's where we differ, I'll take any type of snow event, 2-4, 3-6, 4-8 incher etc.

[NJwinter23]

I really am encouraged for the potential of some moderate overrunning storms in that pattern. Atlantic ridiculous, Pacific atrocious..cant see a KU happening in that but come on now, we need to go back to reality I think after last winter (and this whole decade for that matter).

[mattinpa]

Tonight's 00z GFS has a pretty classic -NAO block...and the vortex in SE canada also allows for some interesting possibilities.

Still looked pretty interesting in the D8-10 range. Another cutter in the LR, but it seems the GFS liked either big snowtorms in the super-extended or cuts too easily.

[Isotherm]

I really am encouraged for the potential of some moderate overrunning storms in that pattern. Atlantic ridiculous, Pacific atrocious..cant see a KU happening in that but come on now, we need to go back to reality I think after last winter (and this whole decade for that matter).

I'd definitely be more than happy with a 3-6" snow pack heading into Christmas, as I think most would.

[bmc10]

The cold and block seem apparent, just need something to enter the mix. Can't complain when some of the ingredients are in place. Maybe a spike in the PNA in the 8-12 allows for something to come north, like many have stated, an overrunning event. Most important is, I know the cold/dry pattern is frustrating, but it is still early in the winter, be patient. Lot's of time left.

[tombo82685]

the day 10 euro is still locked into a solid west based -nao

[bmc10]

the day 10 euro is still locked into a solid west based -nao

Maybe something can happen down the road, if the block relaxes slightly.

[easternsnowman]

I'm really hoping we can get a clipper to amplify down the PNA ridge that the models seem to show around Day 7/8; that looks to be the next significant s/w for the NYC metro area to watch. Here's what the 18z GFS shows, a permutation of a similar idea of a PNA spike towards neutral/a bit positive. Unfortunately, this run doesn't develop the western ridge completely so the shortwave ejects very flat and eventually minors out, but it's a decent set-up with a confluent 50/50 low as well as a 1064mb arctic high sitting in Canada:

It has been strengthening a lot at the surface recently despite the warming in subsurface anomalies that took place around mid-November. Here is a comparison of Pacific SSTs from now, 3 days ago, and a week ago.

Current:

3 Days Ago:

On this one I'll go with the pros especially DT

Week Ago:

You can really see a cold pool expanding around 140W as well as major cooling in the eastern regions with colder waters all the way from Region 3 to Central America. Still under heavy trade winds too with the SOI averaging around +25 to +30 lately.

Meh...the damage has already been done in terms of the Pacific. It's way too late in the winter for a reversal to more Niño-like patterns of tropical forcing. We have a Niña that is in the low-end strong category in early December and still building.

[easternsnowman]

I'll trust the pros on this one and picking out maps on specific days does'nt prove anything.

[Animal]

I'll trust the pros on this one and picking out maps on specific days does'nt prove anything.

I checked the 6 Z GFS this morning going out 200+ hours and i did not see anything that looked great for storms showing up yet for the PHL-NYC metro areas.

Obviously this can change, but it looked cold and dry with some small chances of snow showers after the storm in a few days.

[Allsnow]

I'll trust the pros on this one and picking out maps on specific days does'nt prove anything.

What are the pros saying? For the recored i would put the people that posted in this thread so far on a pro level