The Winter 2010-11 NYC/PHL Medium Range Thread

[A-L-E-X]

How did you get that high? I've been holding at around 54.8 for over an hour.

It got to 60.1 somehow at 1 PM and then the seabreeze kicked in and now its down to 57.

[tombo82685]

Dt thinks some cold will come but the extremem cold that the gfs is showing is complete crap.

[Sundog]

Dt thinks some cold will come but the extremem cold that the gfs is showing is complete crap.

Well that's not exactly going out on a limb considering its the GFS at 240+ hours.

[Allsnow]

Dt thinks some cold will come but the extremem cold that the gfs is showing is complete crap.

what does the euro think?

[blazess556]

18z GFS looks like it squashes the Southeast ridge a little. Plus there are huge changes out west in the pacific.

[tombo82685]

what does the euro think?

only goes out to 240 hrs, but continues to delay the cold, looks like the cold air comes in with that storm that the gfs has possibly giving some area some snow in n mid atl. The euro has that going to buffalo and the cold air behind that.

[tombo82685]

You want the core of the highest height anomalies to be over Davis Straight/Baffin Island and even back toward Hudson Bay region for a west based block. If you look at the image posted above, you can see the core of the high anomalies are E of Greenland with a closed off contour out toward Iceland. That's definitely a more east based -NAO.

thats what i thought will, but someone said over greenland is west based still.

[Rainshadow]

You want the core of the highest height anomalies to be over Davis Straight/Baffin Island and even back toward Hudson Bay region for a west based block. If you look at the image posted above, you can see the core of the high anomalies are E of Greenland with a closed off contour out toward Iceland. That's definitely a more east based -NAO.

Tombo,

What Will posted.

[usedtobe]

only goes out to 240 hrs, but continues to delay the cold, looks like the cold air comes in with that storm that the gfs has possibly giving some area some snow in n mid atl. The euro has that going to buffalo and the cold air behind that.

The euro idea is probably best though at that time range, no model is good. The big question mark is when the cold come in, how cold will it be and how long will it stay. Not sure of either of those things. I do think we see a stretch of below normal weather after Turkey day and still like Dec averaging below normal but this year, I have little confidence in getting months right before they begin.

[Dsnowx53]

Oh hi there, polar vortex. Would you like to come in?

[Dsnowx53]

Wow, there is a split flow at the end of this run! Having the huge PV and the west-based -NAO allows the flow to buckle and split. Damn, would that be nice.

The Euro Ensembles were apparently hinting at this, too.

[jrodd321]

I know this is 384, but damn does this look familiar to anyone?

[nzucker]

Wow, there is a split flow at the end of this run! Having the huge PV and the west-based -NAO allows the flow to buckle and split. Damn, would that be nice.

The Euro Ensembles were apparently hinting at this, too.

I dunno, there might be some fun times ahead after Thanksgiving but the cold pattern keeps getting delayed. The GFS doesn't get any cold in until after Day 10 which is essentially the fantasy range.

[mattinpa]

I dunno, there might be some fun times ahead after Thanksgiving but the cold pattern keeps getting delayed. The GFS doesn't get any cold in until after Day 10 which is essentially the fantasy range.

It seems to just be the timing of the frontal passage. Pattern still has looked good overall for the past few runs, IMO.

[nzucker]

It seems to just be the timing of the frontal passage. Pattern still has looked good overall for the past few runs, IMO.

There'll definitely be a cold period after the Thanksgiving holiday with a -NAO developing, but we start to lose cross-polar flow at that point. The frontal passage is delayed until the cold air that you need for I-95 snow in late November/early December has left Canada for the most part, and then you have the NAO trying to fight against a very unfavorable Pacific with a +EPO. If the NAO breaks down at all or develops slightly more east-based than expected, temperatures will be above average for the East Coast. I like the look of the Atlantic, but unfortunately the Pacific regime starts to break down at the wrong moment. Don't expect much help from the Pacific in the next few weeks with a weak MJO signal, -AAM, and trade winds strengthening the La Niña. Hopefully we can tap the remaining cold air in Canada for a snow event with a west-based -NAO, but I don't think the pattern is nearly as favorable as some have assumed.

[earthlight]

There'll definitely be a cold period after the Thanksgiving holiday with a -NAO developing, but we start to lose cross-polar flow at that point. The frontal passage is delayed until the cold air that you need for I-95 snow in late November/early December has left Canada for the most part, and then you have the NAO trying to fight against a very unfavorable Pacific with a +EPO. If the NAO breaks down at all or develops slightly more east-based than expected, temperatures will be above average for the East Coast. I like the look of the Atlantic, but unfortunately the Pacific regime starts to break down at the wrong moment. Don't expect much help from the Pacific in the next few weeks with a weak MJO signal, -AAM, and trade winds strengthening the La Niña. Hopefully we can tap the remaining cold air in Canada for a snow event with a west-based -NAO, but I don't think the pattern is nearly as favorable as some have assumed.

Good post. Alot of the pattern development is still up in the air at the moment. We're going to have to watch carefully over the next several days. The past few days have been pretty tumultuous as far as medium-range guidance goes. We've seen several key changes in the Pacific that have altered the general pattern idea. That being said, one thing remains consistent, and probably a potentially good sign..the ridging near Greenland remains.

[mattinpa]

Good post. Alot of the pattern development is still up in the air at the moment. We're going to have to watch carefully over the next several days. The past few days have been pretty tumultuous as far as medium-range guidance goes. We've seen several key changes in the Pacific that have altered the general pattern idea. That being said, one thing remains consistent, and probably a potentially good sign..the ridging near Greenland remains.

Yeah, if that ridging stays, then we could see some late Nov./early Dec fun. I don't know if it will last the whole month of Dec., but it seems favorable for a period of wintry weather to me.

[nzucker]

Yeah, if that ridging stays, then we could see some late Nov./early Dec fun. I don't know if it will last the whole month of Dec., but it seems favorable for a period of wintry weather to me.

I think December will be our best month based on what models are showing with the -NAO, Niña climatology, and the fact that the polar vortex is just beginning to develop so the +QBO/solar min shouldn't be as much of an obstacle as later in the winter. I'm hoping the La Niña peaks early so that we can have a bookend winter with a good March, but that's still up in the air as trade winds are intensifying again with a dropping AAM and stagnant MJO.

[NJwinter23]

I dunno, there might be some fun times ahead after Thanksgiving but the cold pattern keeps getting delayed. The GFS doesn't get any cold in until after Day 10 which is essentially the fantasy range.

It definitely seems to be getting pushed back on the models, however, if you go back to some of the threads from last week (when the long range gfs especially was really hammering the cold idea starting this weekend into the beginning of Thanksgiving week), quite a few of the Mets and forecasters were discussing how this may be too early (the Euro and other models werent as quick as the gfs), and to look out more towards the end of the month 25th and beyond. This idea is still very much on the table, even if we end up more above average then anticipated the beginning of next week.

[earthlight]

[Isotherm]

The later the pattern change occurs, the better. Who wants a wasted favorable pattern before December 5th -- we rarely get significant snow before that time anyway. It looks to me like the -NAO/AO signal is almost a lock at this point, and IMO it could persist for quite awhile. Initially the PNA will be so strongly negative due to the extreme pos height anomaly near the Aleutians, resulting in a deep Western trough and SE-ridge. However, the PNA will be relaxing and heading towards neutral values as we approach early December. This is all we need w/ a -NAO of the magnitude depicted on modelling. Our autumn pattern has followed the progression of 1955 quite well, and I believe that will carry over into December w/ a colder than normal signal in the Lakes/Northeast.

Just think back to the Nina winters of 2007-08, 1998-99, etc, never was blocking of his magnitude depicted on modelling, even in the medium to long range. Low aa/geomag hangover from the past couple years FTW! I for one am cautiously optimistic about the December pattern. It's essentially as good as you can get for Nina of this intensity

[Isotherm]

It definitely seems to be getting pushed back on the models, however, if you go back to some of the threads from last week (when the long range gfs especially was really hammering the cold idea starting this weekend into the beginning of Thanksgiving week), quite a few of the Mets and forecasters were discussing how this may be too early (the Euro and other models werent as quick as the gfs), and to look out more towards the end of the month 25th and beyond. This idea is still very much on the table, even if we end up more above average then anticipated the beginning of next week.

Seems to happen almost all the time. Pattern changes tend to be rushed by 1-2 weeks on modelling. As I said, for us that should be good news since a pattern favorable for snow is worthless before about December 5th.

[Weathergun]

I don't like the 0z/16 GFS op at all in the long range. Especially how it handles the PV. The ECMWF Ensemble and NCEP Ensemble means show colder arriving by thanksgiving weekend. Looks like it hang around longer due to the more west -NAO and PV over SE Canada. I wouldn't be suprised to see winter storm threat that weekend or thereafter:

[phlwx]

Given the quickness of the northern flow so far this season, I'm not sure any pattern change will be lengthy. This pattern "changes" have been suggesting transitions and quick changes from below to above average...such is life in the battle zone. I'm not doubting there will be cold shots but I don't think we're going to see 2-3 wks solid below average. Temps might average below but we'll probably bounce around a fair bit, especially south of NYC.

[tombo82685]

0z euro is blah, very east based nao, se ridge flexing its muscles in the long run, nothing like the gfs

[Weathergun]

Given the quickness of the northern flow so far this season, I'm not sure any pattern change will be lengthy. This pattern "changes" have been suggesting transitions and quick changes from below to above average...such is life in the battle zone. I'm not doubting there will be cold shots but I don't think we're going to see 2-3 wks solid below average. Temps might average below but we'll probably bounce around a fair bit, especially south of NYC.

Oh, I fully expect there will be periods of moderation. But the pattern favors cold shots last longer than 1 or 2 days.

0z euro is blah, very east based nao, se ridge flexing its muscles in the long run, nothing like the gfs

The ensemble means have been more consistent with gradual west -NAO in the long term. I would follow that more than op runs. Which always change alot.

[phlwx]

Oh, I fully expect there will be periods of moderation. But the pattern favors cold shots last longer than 1 or 2 days.

With the dominance of the Pacific on the pattern we might be able to coax a solid week but I don't think we're going to get a "locked" pattern that lasts 2-3 wks even though modeling is more favorable...last week was modeling a solid shot from this weekend on and that has melted down to a one day cold shot before we're back at/above average on Saturday. The average on the whole will probably be slightly below average but I don't foresee weeks of uninterrupted cold compared to average.

It'll be a fun ride this winter though -- lots of variety in the cards.

[NorEaster27]

A strong east based NAO is pretty useless in Dec, in fact the SE ridge may be able to flex its muscle more in response.

[Analog96]

With the dominance of the Pacific on the pattern we might be able to coax a solid week but I don't think we're going to get a "locked" pattern that lasts 2-3 wks even though modeling is more favorable...last week was modeling a solid shot from this weekend on and that has melted down to a one day cold shot before we're back at/above average on Saturday. The average on the whole will probably be slightly below average but I don't foresee weeks of uninterrupted cold compared to average.

It'll be a fun ride this winter though -- lots of variety in the cards.

And it's going to be warm on Sunday, right? When NYC doesn't make 45 degrees. The GFS has been very consistent in advertising that Turkey Day is when the real cold gets here, and it actually has gotten colder (there are also a couple snow threats this run, but temps are easier to predict at that range). What I don't understand is why people think the cold is gettting pushed back, because it's not cold NOW? It was never supposed to be. The cold air and pattern change is perfectly on track!

[Guest Kramer]

And it's going to be warm on Sunday, right? When NYC doesn't make 45 degrees. The GFS has been very consistent in advertising that Turkey Day is when the real cold gets here, and it actually has gotten colder (there are also a couple snow threats this run, but temps are easier to predict at that range). What I don't understand is why people think the cold is gettting pushed back, because it's not cold NOW? It was never supposed to be. The cold air and pattern change is perfectly on track!

People see what they want to see and say what they want to say. Fact of the matter is the cold is exactly on time, Turkey Day. Not only that, people need to put down these NAO charts and LOOK at the 500 mb maps. A 550 block over greenland extending into the Davis Strait is a west based block, I don't need a computer to tell me that and its not east based.

Sometimes I wonder if we are too obsessed with figuring out a pattern instead of just seeing and reacting. Turkey Day and beyond most def. has the look of a west based NAO with either a split flow or possible western ridging with plenty of vortexes in the pipe line. That is good news with -10 850's hanging around a nice snow pack building over Southern Canada.