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January Forecast Discussion


REDMK6GLI

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Great discussion!

 

Only issue I have with getting excited for big snow storms in this pattern is the lack of true blocking over the N Atl to Greenland. Heights rise over N Greenland but we're maintaining this N Atl ridge pattern. So we drop this anomalous trough into the eastern US, up against the ridge, and upper level winds are screaming from the S/SW. Certainly a baroclinic environment, and the monster ridge in the west favors amplifying disturbances, so east coast cyclogenesis potential looks great. But without more of a block to the NE, looks like a pattern that'll have 980mb lows zipping by with 6 hours of snow. Granted that can easily be a 10" storm, but in the great quest for a MECS, I would want more blocking.

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Great discussion!

Only issue I have with getting excited for big snow storms in this pattern is the lack of true blocking over the N Atl to Greenland. Heights rise over N Greenland but we're maintaining this N Atl ridge pattern. So we drop this anomalous trough into the eastern US, up against the ridge, and upper level winds are screaming from the S/SW. Certainly a baroclinic environment, and the monster ridge in the west favors amplifying disturbances, so east coast cyclogenesis potential looks great. But without more of a block to the NE, looks like a pattern that'll have 980mb lows zipping by with 6 hours of snow. Granted that can easily be a 10" storm, but in the great quest for a MECS, I would want more blocking.

Yeah, although with the PV so close to us you'd still want any blocking to be relatively weak and you also need a SE ridge to some extent.
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Great discussion!

Only issue I have with getting excited for big snow storms in this pattern is the lack of true blocking over the N Atl to Greenland. Heights rise over N Greenland but we're maintaining this N Atl ridge pattern. So we drop this anomalous trough into the eastern US, up against the ridge, and upper level winds are screaming from the S/SW. Certainly a baroclinic environment, and the monster ridge in the west favors amplifying disturbances, so east coast cyclogenesis potential looks great. But without more of a block to the NE, looks like a pattern that'll have 980mb lows zipping by with 6 hours of snow. Granted that can easily be a 10" storm, but in the great quest for a MECS, I would want more blocking.

Aren't you, Adam and Hm talking about that very thing on twitter lately? ;-)

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For a downwelling SSW, true -NAO blocking develops in February

Till then, ( which I hope materializes) we're stuck with a progressive flow. It can snow in this scenario, as proven in December. Little shows for now, maybe blockbuster later mid feb

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Great discussion!

 

Only issue I have with getting excited for big snow storms in this pattern is the lack of true blocking over the N Atl to Greenland. Heights rise over N Greenland but we're maintaining this N Atl ridge pattern. So we drop this anomalous trough into the eastern US, up against the ridge, and upper level winds are screaming from the S/SW. Certainly a baroclinic environment, and the monster ridge in the west favors amplifying disturbances, so east coast cyclogenesis potential looks great. But without more of a block to the NE, looks like a pattern that'll have 980mb lows zipping by with 6 hours of snow. Granted that can easily be a 10" storm, but in the great quest for a MECS, I would want more blocking.

I agree with this concern in full. I think the issue for me moving forward is how and when does this gyre of sorts retrograde farther west than Central Canada? This is always the issue in these retrograding pattern progressions.

In 2010 we saw it retrograde to a perfect spot and we had the big time blocking build into the Davis Straight at the same time. And so that progression was absolutely classic and nearly perfect -- textbook. I don't think we can compare this to that yet until we see some sustained high latitude blocking development. But what we are seeing on medium range guidance is a big first step toward it.

Anyway...the other thing getting my attention is the potential split flow development once the ridge retrogrades back off the west coast. With the PV just north of us in Canada and increasing moisture available..a load of possibilities there too.

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Great discussion!

 

Only issue I have with getting excited for big snow storms in this pattern is the lack of true blocking over the N Atl to Greenland. Heights rise over N Greenland but we're maintaining this N Atl ridge pattern. So we drop this anomalous trough into the eastern US, up against the ridge, and upper level winds are screaming from the S/SW. Certainly a baroclinic environment, and the monster ridge in the west favors amplifying disturbances, so east coast cyclogenesis potential looks great. But without more of a block to the NE, looks like a pattern that'll have 980mb lows zipping by with 6 hours of snow. Granted that can easily be a 10" storm, but in the great quest for a MECS, I would want more blocking.

 

 

The types of large snowstorms in this pattern are generally Miller Bs...but they are hard to get into KU status. January 1961 was able to pull it off in a very similar pattern progged. January 2005 was somewhat similar, though I liked the Atlantic a tad bit more in that setup than our upcomibng pattern. Both were Miller Bs.

 

But I'd probably favor a series of smaller events at this point. But sometimes those clipper/redevelopers can surprise.

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I agree with this concern in full. I think the issue for me moving forward is how and when does this gyre of sorts retrograde farther west than Central Canada? This is always the issue in these retrograding pattern progressions.In 2010 we saw it retrograde to a perfect spot and we had the big time blocking build into the Davis Straight at the same time. And so that progression was absolutely classic and nearly perfect -- textbook. I don't think we can compare this to that yet until we see some sustained high latitude blocking development. But what we are seeing on medium range guidance is a big first step toward it.Anyway...the other thing getting my attention is the potential split flow development once the ridge retrogrades back off the west coast. With the PV just north of us in Canada and increasing moisture available..a load of possibilities there too.

transient blocks occur in these patterns John, cripes just look at Boston blizzard this month. You wrote a beautiful piece, laying out very well the options.
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The types of large snowstorms in this pattern are generally Miller Bs...but they are hard to get into KU status. January 1961 was able to pull it off in a very similar pattern progged. January 2005 was somewhat similar, though I liked the Atlantic a tad bit more in that setup than our upcomibng pattern. Both were Miller Bs.

But I'd probably favor a series of smaller events at this point. But sometimes those clipper/redevelopers can surprise.

exactly I don't think John is calling for a KU either but certainly some of our great snowstorms have occurred with very similar setups.
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I agree with this concern in full. I think the issue for me moving forward is how and when does this gyre of sorts retrograde farther west than Central Canada? This is always the issue in these retrograding pattern progressions.In 2010 we saw it retrograde to a perfect spot and we had the big time blocking build into the Davis Straight at the same time. And so that progression was absolutely classic and nearly perfect -- textbook. I don't think we can compare this to that yet until we see some sustained high latitude blocking development. But what we are seeing on medium range guidance is a big first step toward it.Anyway...the other thing getting my attention is the potential split flow development once the ridge retrogrades back off the west coast. With the PV just north of us in Canada and increasing moisture available..a load of possibilities there too.transient blocks occur in these patterns John, cripes just look at Boston blizzard this month. You wrote a beautiful piece, laying out very well the options.

Thanks man. Means a lot espec. coming from someone like yourself, Scott, etc.

The transient blocks definitely occur, and can often be timed well too. But as far as really slowing down the flow and talking about something more established in the higher latitudes, I think we will have to wait a little longer for the strat warming to really down well.

I haven't been able to check the vectors lately -- where are we at with that? They were looking decent as recently as Monday.

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exactly I don't think John is calling for a KU either but certainly some of our great snowstorms have occurred with very similar setups.

 

 

Oh I didn't say he was. I was just agreeing with Sam that bigger storms are tough to come by in this pattern. Even with a transient block...you saw how the Jan 2-3 storm just scooted quickly once the coastal developed and was pretty far SE. That "block" in Greenland was barely worth the name. It was pretty weak...though it certainly didn't hurt.

 

 

But the big storms can still happen. I gave two examples. Preferably to slow things down without a true block is to get a pretty potent 50/50 feature well-timed and it can basically act as block temporarily. The reason we love Greenland blocks is that they basically force a semi-permanent 50/50 feature

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The types of large snowstorms in this pattern are generally Miller Bs...but they are hard to get into KU status. January 1961 was able to pull it off in a very similar pattern progged. January 2005 was somewhat similar, though I liked the Atlantic a tad bit more in that setup than our upcomibng pattern. Both were Miller Bs.

 

But I'd probably favor a series of smaller events at this point. But sometimes those clipper/redevelopers can surprise.

 

I don't necessarily disagree with this idea, but I do think that this pattern is retrograding and not necessarily something that is set in stone to only deliver late-developing Miller B's. If the ensemble guidance is correct in bringing the center of the upper level low back over Central Canada, that opens up the door for much more significant amplification farther south, especially when combined with the presence of the big time ridge on the West Coast.

 

Just my thoughts...at this range mostly heresay given the changes we've seen on guidance on a day to day basis. The general idea moving forward though is for a very favorable period essentially from 1/22 onward. 

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I don't necessarily disagree with this idea, but I do think that this pattern is retrograding and not necessarily something that is set in stone to only deliver late-developing Miller B's. If the ensemble guidance is correct in bringing the center of the upper level low back over Central Canada, that opens up the door for much more significant amplification farther south, especially when combined with the presence of the big time ridge on the West Coast.

 

Just my thoughts...at this range mostly heresay given the changes we've seen on guidance on a day to day basis. The general idea moving forward though is for a very favorable period essentially from 1/22 onward. 

 

 

I mentioned back in the New England subforum that I think a more widespread system might be favorable in the final 5 days of the month or so...but the initial pattern for Jan 21-26 or so will not favor that.

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Speaking of 50/50 lows...one has to wonder if we may have multiple chances to slow down the pattern with any phasing system coming around the upper level low in canada. It may not go into the textbook 50/50 position but any rapidly deepening surface low near there could serve to slow down the pattern. 

 

You loop this and you realize we'll probably have more than a few swings at this thing..

 

http://www.meteo.psu.edu/~fxg1/ENSHGTAVGNH_18z/ensloopmref.html

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I agree with this concern in full. I think the issue for me moving forward is how and when does this gyre of sorts retrograde farther west than Central Canada? This is always the issue in these retrograding pattern progressions. In 2010 we saw it retrograde to a perfect spot and we had the big time blocking build into the Davis Straight at the same time. And so that progression was absolutely classic and nearly perfect -- textbook. I don't think we can compare this to that yet until we see some sustained high latitude blocking development. But what we are seeing on medium range guidance is a big first step toward it. Anyway...the other thing getting my attention is the potential split flow development once the ridge retrogrades back off the west coast. With the PV just north of us in Canada and increasing moisture available..a load of possibilities there too.

 

Absolutely. And your emphasis of the importance of the PV enlongation is spot on. That's when we can actually get some real perturbations on the flow

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