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Taking a look into October and November

OKpowdah

By OKpowdah,
in New England

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OKpowdah

OKpowdah

Posted
Posted

I have extremely limited time, but from the glimpses I've taken at the developing pattern I'm becoming more and more interested in how fall 2012 is shaping up for North America.

This week will feature a significant pattern change beginning in the Pacific and extending across NA by next weekend.

Pacific jet energy is poised to dump into western NA by the middle of next week. The weakness in the deep south (hey that's me now!) allows this shear vorticity to dig into one of the first big full-latitude troughs of the season. Upstream, the previously suppressed flat ridge explodes poleward into Alaska.

Meanwhile, we can't forget the train of monster TCs recurving in the WPac. As has been shown, these events can trigger wave dispersion downstream, amplifying ridging over EPac and W NA.

And all of a sudden we have this beautiful massive block forming along 130W. Wow, here we go!

Doing some quick analog math based on the pattern in the past few weeks, I also get potentially a cold November in the cards for the eastern half of the nation.

I think we could get some great discussion on this development, so I figured I would start up this thread and see what happens!

I'll try to post a little more especially as we get these cool larger scale pattern evolutions. I miss New England and its weather! All the best to everyone here

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dryslot

dryslot

Posted
Posted

I have extremely limited time, but from the glimpses I've taken at the developing pattern I'm becoming more and more interested in how fall 2012 is shaping up for North America.

This week will feature a significant pattern change beginning in the Pacific and extending across NA by next weekend.

Pacific jet energy is poised to dump into western NA by the middle of next week. The weakness in the deep south (hey that's me now!) allows this shear vorticity to dig into one of the first big full-latitude troughs of the season. Upstream, the previously suppressed flat ridge explodes poleward into Alaska.

Meanwhile, we can't forget the train of monster TCs recurving in the WPac. As has been shown, these events can trigger wave dispersion downstream, amplifying ridging over EPac and W NA.

And all of a sudden we have this beautiful massive block forming along 130W. Wow, here we go!

Doing some quick analog math based on the pattern in the past few weeks, I also get potentially a cold November in the cards for the eastern half of the nation.

I think we could get some great discussion on this development, so I figured I would start up this thread and see what happens!

I'll try to post a little more especially as we get these cool larger scale pattern evolutions. I miss New England and its weather! All the best to everyone here

Nice read Sam, Looks like the prospects for a decent winter are starting to shape up, AK and the PAC are going to play a vital roll going forward

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Typhoon Tip

Typhoon Tip

Posted
Posted

I have extremely limited time, but from the glimpses I've taken at the developing pattern I'm becoming more and more interested in how fall 2012 is shaping up for North America.

This week will feature a significant pattern change beginning in the Pacific and extending across NA by next weekend.

Pacific jet energy is poised to dump into western NA by the middle of next week. The weakness in the deep south (hey that's me now!) allows this shear vorticity to dig into one of the first big full-latitude troughs of the season. Upstream, the previously suppressed flat ridge explodes poleward into Alaska.

Meanwhile, we can't forget the train of monster TCs recurving in the WPac. As has been shown, these events can trigger wave dispersion downstream, amplifying ridging over EPac and W NA.

And all of a sudden we have this beautiful massive block forming along 130W. Wow, here we go!

Doing some quick analog math based on the pattern in the past few weeks, I also get potentially a cold November in the cards for the eastern half of the nation.

I think we could get some great discussion on this development, so I figured I would start up this thread and see what happens!

I'll try to post a little more especially as we get these cool larger scale pattern evolutions. I miss New England and its weather! All the best to everyone here

Exactly! This should, also, be a good thread going forward for this type of discussion as the other was sort of banter-oriented and Will's winter thread's getting a bit long.

I echoed your sentiments in greater measure this morning in said banter thread, but I believe it more appropriate here - so pasting it in.

It's so early in the season, though, that some modification of cold anomalies as the first couple of masses come south of the Canadian border has to be assumed. Then passing those air masses over the balmy Great Lakes is going to moderate even further. We don't have a snow pack and the sun is still at least tepid in strength. These factors should limit how cool it gets. However, if the blend of the operational Euro and GFS' D5-10 were to play out a month from now? Look out!

The longer term teleconnector mean off the GFS cluster is doubling up the cold signal, converging a target into the OV. There is a tandem +PNA/-NAO(-EPO), during which time there is a -1.5 correction going on with the Arctic Oscillation as we pass deeper into October. None of which appears challenged for duration. It appears these operational runs are really tapping into those background physics because there are no interfering forces in play. We even have recurving TCs in the western Pac Basin, if it were not enough, and now the MJO is strengthening in late Phase 7 (phase 6 first). My goodness - the colors are exploding early too - not that's just getting weird haha.

I mean I don't see how that can all transpire without synoptic snow taking place N of the 40th parallel by the middle of October. Though rare across a 50-year climate mean, sure, we have in recent years witnessed that when parametrics align it is not as hard to snow in October as we may think. It's just getting the frequency of those parameters aligning, which per an entirely different discussion, we seem to be in some odd intra-decadal positive anomaly. Who knows why.

Anyway, it's probably a good measure to see northern plains negative temperature anomalies then take a few successive re-enforcing cool shots to really convincingly press the colder continental air east (eventually) of the eastern Cordillera; but I don't see how that is avoidable given time, given all the above. It's going to be cooler than normal. Quick comment on the geopotential medium: While the absolute anomaly distributions may appear only moderate in scope, the spatial orientation and overall pervasive mass-field involvement in this pattern in the first two weeks of October is pretty f awesome people.

John

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OKpowdah

OKpowdah

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Posted

Exactly! This should, also, be a good thread going forward for this type of discussion as the other was sort of banter-oriented and Will's winter thread's getting a bit long.

I echoed your sentiments in greater measure this morning in said banter thread, but I believe it more appropriate here - so pasting it in.

It's so early in the season, though, that some modification of cold anomalies as the first couple of masses come south of the Canadian border has to be assumed. Then passing those air masses over the balmy Great Lakes is going to moderate even further. We don't have a snow pack and the sun is still at least tepid in strength. These factors should limit how cool it gets. However, if the blend of the operational Euro and GFS' D5-10 were to play out a month from now? Look out!

The longer term teleconnector mean off the GFS cluster is doubling up the cold signal, converging a target into the OV. There is a tandem +PNA/-NAO(-EPO), during which time there is a -1.5 correction going on with the Arctic Oscillation as we pass deeper into October. None of which appears challenged for duration. It appears these operational runs are really tapping into those background physics because there are no interfering forces in play. We even have recurving TCs in the western Pac Basin, if it were not enough, and now the MJO is strengthening in late Phase 7 (phase 6 first). My goodness - the colors are exploding early too - not that's just getting weird haha.

I mean I don't see how that can all transpire without synoptic snow taking place N of the 40th parallel by the middle of October. Though rare across a 50-year climate mean, sure, we have in recent years witnessed that when parametrics align it is not as hard to snow in October as we may think. It's just getting the frequency of those parameters aligning, which per an entirely different discussion, we seem to be in some odd intra-decadal positive anomaly. Who knows why.

Anyway, it's probably a good measure to see northern plains negative temperature anomalies then take a few successive re-enforcing cool shots to really convincingly press the colder continental air east (eventually) of the eastern Cordillera; but I don't see how that is avoidable given time, given all the above. It's going to be cooler than normal. Quick comment on the geopotential medium: While the absolute anomaly distributions may appear only moderate in scope, the spatial orientation and overall pervasive mass-field involvement in this pattern in the first two weeks of October is pretty f awesome people.

John

Very well spelled out! I'm sorry I missed your original post. I'm definitely looking forward to this fall in North America!

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nzucker

nzucker

Posted
Posted

True. My bad

It's really both: I originally thought it was an omega block because of the two powerful ULLs, one near the Aleutians, one in the Southwest, leading to the formation of a strong ridge in between, over Alaska/BC. But it's also true that we have a weakness (the Southwest cut-off low that's so common in El Niño winters) trapped underneath the monster -EPO ridge. The pattern is really starting to resemble El Niño, despite how much difficulty ENSO has had in getting its feet off the ground with colder than normal waters popping up right along the equator and the -PDO signature off Baja California continuing to strengthen with those below average SSTs bleeding towards the ENSO regions as well. However, I see the MJO is chugging towards Phases 6/7, and I wonder if that Niño-like tropical forcing is driving this change towards a -EPO.

The ECMWF 168-240 anomaly map really shows a very strong gradient pattern centered right over New England; someone in the thread already mentioned SWFEs as a potential result as we get deeper into the cold season. I'm starting to wonder if this could be a 93-94 type of warm ENSO pattern heading into the winter, where there's a large -EPO block but the NAO stays near neutral, causing a gradient to form with a frigid polar vortex over Hudson Bay contrasting with a mild Southeast ridge. DCA had 13.2" snowfall that winter whereas BOS had 96.3," surely the greatest disparity in records. It would be interesting if we had a sort of hybrid winter, with the Niño leading to Pacific side blocking and a strong -EPO, but that pattern displacing the polar vortex into Hudson Bay and thus rendering the NAO rather neutral, but in a favorable fashion for those from NYC on north. The GFS maps also show the NAO block being a bit east-based as an ULL dropped south by the -EPO keeps heights lower in the Baffin Island/Foxe Basin/Hudson Bay region.

This could be a fascinating hybrid winter if such a regime continues.

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