The Winter 2010-11 NYC/PHL Medium Range Thread

[MikeS]

What an interesting development and I hope the cold trend verfiies in the coming days. I miss the cold air.

[Analog96]

The full list since 1950 (if you include the borderline '81-'82 year) is:

1955-1956

1961-1962

1964-1965

1965-1966

1967-1968

1968-1969

1970-1971

1978-1979

1981-1982

1984-1985

2008-2009

Where does 1993-94 fit in? I thought that was on this list.

[Manny]

The Upcoming model runs, if they are consistent in depicting a favorable cold air pattern, could determine our state of mind going into Early December. lol

[Riptide]

Alot of amplification, like previous runs.

[blazess556]

12z GFS trended towards a much more interesting solution given how far out it is. Just have to keep watching.

[MJO812]

12z GFS trended towards a much more interesting solution given how far out it is. Just have to keep watching.

The block isn't in a good spot. We need the block to be in a much better spot and the cold air needs to come in faster. Nice south trend. Still a while to go.

[Rainshadow]

I deliberately did not include those lower skilled off sounding runs after the first one, going back to the 00z run on the 12th this is the first forecast time that the gfs had Philly dropping below a forecast 530 thickness. Yeah some of the runs early had sub 530 thicknesses over this weekend (20/21) which have since disappeared.

11/11 18z run - not at all, ok.

12th/00z.....7 pm 27th

12th/12z.....7 am 25th

13th/00z.....7 am 24th

13th/12z.....7 pm 24th

14th/00z.....7 pm 27th

14th/12z.....7 am 26th

15th/00z.....7 am 27th

15th/12z.....7 am 27th

16th/00z.....7 pm 26th

16th/12z.....7 pm 26th

17th/00z.....7 pm 26th

17th/12z.....7 pm 26th

18th/00z.....7 am 26th

18th/12z.....7 am 26th

[MJO812]

The Thanksgiving storm goes through the Lakes on the 12z Euro. Looks like a warm rain here. After that, the arctic floodgates open. It turns really cold.

[tombo82685]

day ten on the 12z euro has a massive west ridge and deep trof over the east, with a storm just missing out to sea. A good west based -nao is also there. Only concern is the goa low, so im not sure if the ridge out west kicks east after day 10, but its a warm between that and the nao

[jrodd321]

Just beautiful.

[tombo82685]

Maybe someone can hlep with this. Are the goa lows good or not? Usually with those lows you have a trof. Isn't that a good placement for the trof though, because that would then pump the ridge in the west then said the trof down in the east?

[Guest Noreaster]

Just beautiful.

If you can get a vort to drop in and bite, yes. Two problems with that

1) No subtropical jet

2) FAST Nina flow, even with the blocking.

Hopefully we get a fish on the line and land it on the boat :snowman: :snowing: :snowing:

[phlwx]

Maybe someone can hlep with this. Are the goa lows good or not? Usually with those lows you have a trof. Isn't that a good placement for the trof thoug, because that would then pump the ridge in the west then said the trof down in the east?

Depends on low placement, broadness of the trough, etc. If the low is too far east in the GOA the downstream ridge may be too close for comfort and you have a NW flow here as the following trough axis is out to sea. The way the Euro is setting up shows cold/dry with nothing in the pipeline after Thanksgiving.

[Nikolai]

Depends on low placement, broadness of the trough, etc. If the low is too far east in the GOA the downstream ridge may be too close for comfort and you have a NW flow here as the following trough axis is out to sea. The way the Euro is setting up shows cold/dry with nothing in the pipeline after Thanksgiving.

I think the models are finally coming around to affirming our first real cold spell 11/25 and later. The Thanksgiving storm is tentatively a lakes cutter, but I think it has some potential--still a week away. Beyond Thanksgiving, I think we see our first snow chance by the end of the month, and the pattern should continue into early December. Everyone should check out how cold Siberia is now getting... potential arctic outbreak after 12/10-15?

Europe is also looking very cold/snowy soon, interestingly enough. I think the -NAO will dominate our pattern, and while we may not always be well below average in December... any slackening of the cold should be temporary, and temps should still be chilly.

[Nikolai]

Trend is our friend

If the 50/50 low can trend stronger/further west, this could be the NY area's first shot at a wintry/mixed accumulating event. Key is to get the 50/50 better!

[Guest Kramer]

Trend is our friend

If the 50/50 low can trend stronger/further west, this could be the NY area's first shot at a wintry/mixed accumulating event. Key is to get the 50/50 better!

respectfully disagree. Look at the map you posted, the real problem is there isn't any true confluence to the north of the LP. Yes, you have a block and 50/50, but look at the pressure fields, the best part of the HP has tucked itself back against the rockies and only a small lobe moved east (coutesy of the se ridging) so the LP really isn't fighting anything. Yes, its harder to cut west of us, but in the end its not the 50/50 or the block, its the lack of true confluence to the north.

If you had a large 1035 or even 1030 arctic HP over southern and central canada, the confluence, block and 50/50 would work in tandum and likely the local area would have a nice overrunning or redevelopment event. We are just a little too early in the season to see that, especially with a lack of deep snow cover in southern canada.

you see it at 500 really clearly

[Nikolai]

respectfully disagree. Look at the map you posted, the real problem is there isn't any true confluence to the north of the LP. Yes, you have a block and 50/50, but look at the pressure fields, the best part of the HP has tucked itself back against the rockies and only a small lobe moved east (coutesy of the se ridging) so the LP really isn't fighting anything. Yes, its harder to cut west of us, but in the end its not the 50/50 or the block, its the lack of true confluence to the north.

If you had a nice 1035 or even 1030 arctic HP over southern canada, the confluence, block and 50/50 would work in tandum and likely the local area would have a nice overrunning or redevelopment event.

We are just a little too early in the season to see that, especially with a lack of deep snow cover in southern canada.

you see it at 500 really clearly

Canada is actually almost completely covered in snow now.

You make very good points, and indeed, the lack of an arctic HP on the 18z is the major problem (partially a result of the 50/50 low's progressive/relatively weak nature this run). I think if HP can settle in earlier--which it certainly could, given the trends--we could be dealing with a threat. This is all obviously tentative, but it's just something to keep an eye on for the next few days.

[Guest Kramer]

Canada is actually almost completely covered in snow now.

You make very good points, and indeed, the lack of an arctic HP on the 18z is the major problem (partially a result of the 50/50 low's progressive/relatively weak nature this run). I think if HP can settle in earlier--which it certainly could, given the trends--we could be dealing with a threat. This is all obviously tentative, but it's just something to keep an eye on for the next few days.

well, there is snow cover, and there is snow cover. Depth is KEY for keeping HP's robust.

Really what we have is just the pacific coming on board a hair too late and the front not getting through in order to let the wave ridge east, not north.

Patience.

[earthlight]

Canada is actually almost completely covered in snow now.

You make very good points, and indeed, the lack of an arctic HP on the 18z is the major problem (partially a result of the 50/50 low's progressive/relatively weak nature this run). I think if HP can settle in earlier--which it certainly could, given the trends--we could be dealing with a threat. This is all obviously tentative, but it's just something to keep an eye on for the next few days.

The problem is that the downstream pattern is not supportive of anything but amplification of the Southeast ridge. The confluence is actually pretty decent on this run of the GFS, but the shortwave still goes well north owing to the ridge heights. There's really not much room for anything else to happen.

This is a good thing, though, as this system sets up the big 50+ above avg DM ridge that builds into Greenland and when coupled with a potentially -/+ PNA could lead to some fresh cold air by the end of the month.

[Guest Kramer]

The problem is that the downstream pattern is not supportive of anything but amplification of the Southeast ridge. The confluence is actually pretty decent on this run of the GFS, but the shortwave still goes well north owing to the ridge heights. There's really not much room for anything else to happen.

This is a good thing, though, as this system sets up the big 50+ above avg DM ridge that builds into Greenland and when coupled with a potentially -/+ PNA could lead to some fresh cold air by the end of the month.

not nearly as good as if the whole HP came out of the rockies which is just not going to happen with, as you say, the downstream pattern.

Its just not there for this storm, but its only November 18, and we have a good three week period here to see something.

[Chris L]

I love the classic Greenland block signature showing up.

And some downstream amplification is starting to show up as well with some spikes (not your claasic PNA by any means) out west.

IF we get this in December, gotta hope that a strong vortmax(es) will dig to carve out a deep trough, and form a Miller A sfc low.

With lack of STJ, the Miller A(s) will be hard to come by.

[earthlight]

With lack of STJ, the Miller A(s) will be hard to come by.

Get used to it, buddy...going to be a repetitive theme this winter.

[Chris L]

Get used to it, buddy...going to be a repetitive theme this winter.

Way ahead of you, I already know that those crazy cutoffs from 2009-2010 are gone.

But, Miller Bs can happen.

[Guest Kramer]

I love the classic Greenland block signature showing up.

And some downstream amplification is starting to show up as well with some spikes (not your claasic PNA by any means) out west.

IF we get this in December, gotta hope that a strong vortmax(es) will dig to carve out a deep trough, and form a Miller A sfc low.

With lack of STJ, the Miller A(s) will be hard to come by.

STJ is not the only way to get a Miller A. Anything that splits out of the northern stream and drops down to the gulf coast can become a Miller A system. We have seen a few vorts split off the polar jet already this year.

However, your chances are significantly reduced.

Regardless, the all or nothing MIller A scenario the area saw last year can actually be WORSE than the nickle and dime with occasional decent storm, ala 2008-2009.

I haven't looked, but I am pretty sure some of the snow totals around the area were HIGHER in 08-09 than 09-10 with the strong STJ.

[am19psu]

Maybe someone can hlep with this. Are the goa lows good or not? Usually with those lows you have a trof. Isn't that a good placement for the trof though, because that would then pump the ridge in the west then said the trof down in the east?

Depends on whether there is a subtropical ridge beneath it (+EPO) or if it is by its lonesome and pumps up a Western ridge (+PNA). Make sense?

[am19psu]

BTW, I totally agree with what HM is saying on the main board. The Pacific looks absolutely awful for cold in December (forced by the tropics). You're really going to need a blocked up Atlantic for any hope of cold after the post-Thanksgiving chill exits.

Nikolai is right, though. With the NH snow cover, there are going to be some brutally cold air masses generated this year. The question is whether the -NAO/-AO cooperates to get them into the Eastern US. My guess is ORD/DSM/OMA win that lottery more often.

[tombo82685]

Depends on whether there is a subtropical ridge beneath it (+EPO) or if it is by its lonesome and pumps up a Western ridge (+PNA). Make sense?

yup makes sense. -epo is the ridge over alaska or just to the east?

[am19psu]

yup makes sense. -epo is the ridge over alaska or just to the east?

Yup. EPO is like an east based NAO for the Pacific.

[tombo82685]

BTW, I totally agree with what HM is saying on the main board. The Pacific looks absolutely awful for cold in December (forced by the tropics). You're really going to need a blocked up Atlantic for any hope of cold after the post-Thanksgiving chill exits.

Nikolai is right, though. With the NH snow cover, there are going to be some brutally cold air masses generated this year. The question is whether the -NAO/-AO cooperates to get them into the Eastern US. My guess is ORD/DSM/OMA win that lottery more often.

till it happens, im still hoping we get some cold and snow chances.

[Rainshadow]

BTW, I totally agree with what HM is saying on the main board. The Pacific looks absolutely awful for cold in December (forced by the tropics). You're really going to need a blocked up Atlantic for any hope of cold after the post-Thanksgiving chill exits.

Nikolai is right, though. With the NH snow cover, there are going to be some brutally cold air masses generated this year. The question is whether the -NAO/-AO cooperates to get them into the Eastern US. My guess is ORD/DSM/OMA win that lottery more often.

That would be my spin on it too. Don't see any stratospheric warning either fcst to go on thru day 10. Would like to see where this "cutter" low actually tracks around Thanksgiving.