Pattern Changing: Early December threats?

[ski MRG]

I could see the 12/1-12/2 storm trending a bit further east and deeper with the secondary. Maybe a surprise for the Berks and Greens?

I enjoy your positive posts much more. What leads you to think this is a possibility ? Strength of the -NAO?

[Damage In Tolland]

As we thought. This possibility has been advertised for a number of days now.

We need to find a wifi-enabled watering hole. Do you know anybody in Worcester who could point us in the right direction?

Will ..if he would ever answer us in the GTG thread

[CoastalWx]

if that what you thought i meant.. you must think i'm a retard. cool.

temp fallng quickly here.......

i must say that last nite /today's' storm did trend cooler.....than modeled

much of extreme N. MA had ice outside 495.... should i say if you look at the weather bug data most sites were 32/31 ish for alot of the morning from just outside the NW part of 495 up thru southern new hamshire....and my temp in framingham was 34 degrees right thru the heaviest precip. I do believe i was supposed to warm a bit more. very close to a decent ice storm IMBY while other's had it....and most in NH had 100% frozen save the immedite SE coast. MPM had ice right thru 95% of precip.

That's not what I meant at all. I never attack people in a condescending way. I was just saying that sometimes that wx will do what it wants.

[40/70 Benchmark]

Well, I understand your thoughts, I guess you can rule it out to a certain point.

Yea....obviously it was technically possible and I know that, but I like to be very emphatic because it makes things more interesting. lol

[CT Rain]

They are all going nutty with the blocking past day 8...lol.

I'm honestly not sure what to make of all this. Everything is so blocked up in the pattern. I think the trends today are definitely good, but who knows what this is going to look like another 48 hours from now. One constant which I am pleased with is the EPO dump of frigid air into Canada...hopefully we can spread a nice sfc high to bring that southeast for some of the setups upcoming

What's weird is how changeable the EPO signal has been. Take the 12z GEFS they have a nice ridge in the Bering Strait but keep a closed low/+EPO signal off and on in the GOA and near British Columbia for virtually the entire run.

I'm thinking even losing the -EPO and flipping it to a +EPO isn't a bad thing if we can force a +PNA ridge to battle the SE ridge.

[CoastalWx]

What's weird is how changeable the EPO signal has been. Take the 12z GEFS they have a nice ridge in the Bering Strait but keep a closed low/+EPO signal off and on in the GOA and near British Columbia for virtually the entire run.

I'm thinking even losing the -EPO and flipping it to a +EPO isn't a bad thing if we can force a +PNA ridge to battle the SE ridge.

I think the 12z ecm ensembles show the result of when a +EPO can be a good thing. It's basically a weak GOA trough that is tilted from sw-ne (positively tilted) and also in the central GOA. It actually pops a weak ridge over the west.

[40/70 Benchmark]

What's weird is how changeable the EPO signal has been. Take the 12z GEFS they have a nice ridge in the Bering Strait but keep a closed low/+EPO signal off and on in the GOA and near British Columbia for virtually the entire run.

I'm thinking even losing the -EPO and flipping it to a +EPO isn't a bad thing if we can force a +PNA ridge to battle the SE ridge.

I agree because more often than not (nothing is absolute with respect to synoptic meteorology) having somewhat of a battle raging is optimal at this latitide; we don't want every indicator in the universe plunging the arctic into Ft. Lauderdale.

[CT Rain]

I think the 12z ecm ensembles show the result of when a +EPO can be a good thing. It's basically a weak GOA trough that is tilted from sw-ne (positively tilted) and also in the central GOA. It actually pops a weak ridge over the west.

It's hard to actually judge what the EPO value will compute to given a closed low SE of Anchorage and a ridge popping past Nome in the Bering Strait.

I think the ideal scenario for us is a near neutral EPO with a ridge in western Alaska to help dislodge the cold from the Pole and a trough/closed low in the eastern GOA to promote some downstream ridging in the PNA region.

What we're seeing is a classic Nina pattern with a weak or non existent STJ that's really causing the SE ridge to screw us especially with a -PNA pattern helping it. I think in a Nino year we'd probably be much better off in a -PNA/-NAO pattern than during a Nina with a SE ridge that's been cutting storms way west.

[Damage In Tolland]

Good news from JB

Enjoy it now, 'cause the beginning of the end of winter, at least in comparison to last year, is now showing up. The early season winter idea said December is the month, but the turnaround this year could be even more than I am implying now.

[40/70 Benchmark]

Good news from JB

Enjoy it now, 'cause the beginning of the end of winter, at least in comparison to last year, is now showing up. The early season winter idea said December is the month, but the turnaround this year could be even more than I am implying now.

Who cares what he says lol.....could be calling for a blizzard and I ignore that to.

[CoastalWx]

Weeklies are in.

The 7th until the 13th shows a pretty deep trough over the east in response to the strong Davis Strait block. Also some ridging over the southwest with a +epo. That is definitely an interesting setup over the east.

The third week has some ridging again in CA but also a stronger +epo. It also had a very weak, west based -nao. Slightly below normal heights in the east. Verbatim it's a firehose into CA, but the jet appears to be running south of us and not cutting west.

4th weak shows a +epo again with some more ridging in the southwest. However, a narrow area of above normal heights extend to the northeast from the 4 corners, right into se Canada. It also shows strong ridging just south of Greenland that looks like it's trying to build north. We have below normal heights over the southeast and northwest, right on either side of that ridge anomaly that I mentioned extending from the 4 corners region to se Canada.

[ORH_wxman]

The flipping to the +EPO (actually its not even a +EPO...its still quite negative, despite a vortex appearing in part of the EPO region) on these runs isn't bad for three reasons:

1. The initial -EPO has already dumped a lot of cold air into Canada

2. The trough is not over the Bering Straight and W AK area...its more to the south and SSE which can pop a slight PNA ridge at times

3. North of the vortex, there is actually still cross polar flow...almost like a split flow as illustrated below:

[40/70 Benchmark]

Weeklies are in.

The 7th until the 13th shows a pretty deep trough over the east in response to the strong Davis Strait block. Also some ridging over the southwest with a +epo. That is definitely an interesting setup over the east.

The third week has some ridging again in CA but also a stronger +epo. It also had a very weak, west based -nao. Slightly below normal heights in the east. Verbatim it's a firehose into CA, but the jet appears to be running south of us and not cutting west.

4th weak shows a +epo again with some more ridging in the southwest. However, a narrow area of above normal heights extend to the northeast from the 4 corners, right into se Canada. It also shows strong ridging just south of Greenland that looks like it's trying to build north. We have below normal heights over the southeast and northwest, right on either side of that ridge anomaly that I mentioned extending from the 4 corners region to se Canada.

I'm a little confused as to how the 4th week is here....could you please elaborate; thx.

[CoastalWx]

Weeklies are in.

The 7th until the 13th shows a pretty deep trough over the east in response to the strong Davis Strait block. Also some ridging over the southwest with a +epo. That is definitely an interesting setup over the east.

The third week has some ridging again in CA but also a stronger +epo. It also had a very weak, west based -nao. Slightly below normal heights in the east. Verbatim it's a firehose into CA, but the jet appears to be running south of us and not cutting west.

4th weak shows a +epo again with some more ridging in the southwest. However, a narrow area of above normal heights extend to the northeast from the 4 corners, right into se Canada. It also shows strong ridging just south of Greenland that looks like it's trying to build north. We have below normal heights over the southeast and northwest, right on either side of that ridge anomaly that I mentioned extending from the 4 corners region to se Canada.

And yes the common theme is the ridging into the Aleutians and into the Bering Sea.

[ORH_wxman]

It's hard to actually judge what the EPO value will compute to given a closed low SE of Anchorage and a ridge popping past Nome in the Bering Strait.

I think the ideal scenario for us is a near neutral EPO with a ridge in western Alaska to help dislodge the cold from the Pole and a trough/closed low in the eastern GOA to promote some downstream ridging in the PNA region.

What we're seeing is a classic Nina pattern with a weak or non existent STJ that's really causing the SE ridge to screw us especially with a -PNA pattern helping it. I think in a Nino year we'd probably be much better off in a -PNA/-NAO pattern than during a Nina with a SE ridge that's been cutting storms way west.

Agreed 100%...this is what I was trying to demonstrate in the post with the image...but you posted this before I finished with mine.

[CT Rain]

Will, what's the difference between how Alan computes the EPO and ESRL...

http://raleighwx.americanwx.com/models/12zensindices.html

http://www.esrl.noaa.gov/psd/forecasts/teleconn/images/epo.png

Do you have any idea?

I agree with your post... seeing the Bering Strait ridge and troughing/low in the GOA is pretty solid for us.

I think the key for us over the next month is keeping the PNA either neutral or somewhat positive in order to prevent the SE Ridge from flexing too much. The -PNA pattern just isn't cutting it.

[CoastalWx]

Agreed 100%...this is what I was trying to demonstrate in the post with the image...but you posted this before I finished with mine.

That split flow would do wonders too, especially with the -nao.

[40/70 Benchmark]

Thanks....looks like a hair above avg heights......essentially neutral pattern.

[CoastalWx]

It's hard to actually judge what the EPO value will compute to given a closed low SE of Anchorage and a ridge popping past Nome in the Bering Strait.

I think the ideal scenario for us is a near neutral EPO with a ridge in western Alaska to help dislodge the cold from the Pole and a trough/closed low in the eastern GOA to promote some downstream ridging in the PNA region.

What we're seeing is a classic Nina pattern with a weak or non existent STJ that's really causing the SE ridge to screw us especially with a -PNA pattern helping it. I think in a Nino year we'd probably be much better off in a -PNA/-NAO pattern than during a Nina with a SE ridge that's been cutting storms way west.

I agree, I think it would probably be near neutral or perhaps only slightly + as well. I should refer to it as the GOA low in order to avoid confusion.

[CT Rain]

Agreed 100%...this is what I was trying to demonstrate in the post with the image...but you posted this before I finished with mine.

Your post was more clear with the image lol.

But I really think we're getting to a point where the models are showing what we want them to show lol.

[ORH_wxman]

That 4th week is starting to look pretty crappy on the weeklies. The low heights are retrograding into the uglier part of the EPO region and the NAO is turning to crap too...hopefully its wrong, lol.

[CT Rain]

I agree, I think it would probably be near neutral or perhaps only slightly + as well. I should refer to it as the GOA low in order to avoid confusion.

Yeah a +EPO isn't going to kill us by any means. A transient -EPO to dislodge the cold followed by a +EPO would be solid too.

[40/70 Benchmark]

That 4th week is starting to look pretty crappy on the weeklies. The low heights are retrograding into the uglier part of the EPO region and the NAO is turning to crap too...hopefully its wrong, lol.

I know...noticed that.

[CT Rain]

That 4th week is starting to look pretty crappy on the weeklies. The low heights are retrograding into the uglier part of the EPO region and the NAO is turning to crap too...hopefully its wrong, lol.

Yeah that's what we don't want to see... that's starting to torch conus lol

[MaineJayhawk]

That 4th week is starting to look pretty crappy on the weeklies. The low heights are retrograding into the uglier part of the EPO region and the NAO is turning to crap too...hopefully its wrong, lol.

Any idea what the 4th week verification might be? I'm guessing (perhaps hoping) rather low.

[Mr Torchey]

That 4th week is starting to look pretty crappy on the weeklies. The low heights are retrograding into the uglier part of the EPO region and the NAO is turning to crap too...hopefully its wrong, lol.

I really cant take another grinch storm or warmup right before xmas, some great decembers the last few years only to be ruined just before xmas.

[ORH_wxman]

Any idea what the 4th week verification might be? I'm guessing (perhaps hoping) rather low.

Its pretty low, so yeah, I wouldn't sweat it yet. Just making a comment on thats the type of pattern we do not want to see.

[CoastalWx]

Yeah a +EPO isn't going to kill us by any means. A transient -EPO to dislodge the cold followed by a +EPO would be solid too.

Yeah definitely. We talked about how a GOA low isn't a bad thing in the central GOA if it does sort of create split flow. You and Will outlined the battle plan for this pattern. -EPO ridge to dump the cold into Canada, ridging out west or up in western Canada to slide some of the cold east, and NAO blocking to help fight rising heights in the east (if we do pop a -pna or trough in the southwest).

[powderfreak]

I see the Lake Erie band is making it all the way to the southeastern Dacks (barely) on the wsw flow. Maybe the Ontario band (once formed well) will head toward SLK and even N. VT. Although I guess the Greens kill that ever making it over.

Luckily I'm tucked in decently close to Mount Mansfield... and sort of fall under its umbrella of weather. Things usually dry out just a mile or two further down the road. Plenty of times so far this fall I've seen it precipitating here at my location between the village center and the ski resort, while the roads are dry down in the center of town.

[CT Rain]

Yeah definitely. We talked about how a GOA low isn't a bad thing in the central GOA if it does sort of create split flow. You and Will outlined the battle plan for this pattern. -EPO ridge to dump the cold into Canada, ridging out west or up in western Canada to slide some of the cold east, and NAO blocking to help fight rising heights in the east (if we do pop a -pna or trough in the southwest).

I think the last thing we want to see is a retrograding GOA low back toward the Aleutians... then we get to torch city.

The last couple weeks have shown us how tenacious the SE ridge is. The -NAO has muted it significantly (we would have totally torched without it) but until the Pac cooperates getting sustained below normal and more substantial snow threats (beyond front end thumps/SWFEs) will be hard.