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Meteorological Winter Discussion, Always In Season


hm2
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The medium range progression with torques is classic. The effect of this anticyclone-down-the-slopes routine will be added +AAM and ultimately a N PAC jet extension. This will bring back a deeper N PAC low / more classic Niño pattern.

 

Because the EPO dislodges some cold air, the transition from SE RIDGE / -EPO pattern to PNA to Canonical Nino may open up a chance for us to get a wintry event in early Dec. However, this isn't a pattern for big snows or anything with raging +NAO etc.

 

This MT event and subsequent N PAC low will develop the stratospheric Aleutian High / wave 1 stress. However, models already showing the next Siberian attack at the end of the month / early Dec which could bring the next wave 2 stress.

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From HM:

 

Some caveats:

 

1. IF the EPO high fails to fully develop or ends up less pronounce, it could mean very little for this early Dec chance (since it's the cold source).

 

2. The Niño heater effect could erode things by the time something amplifies. Between that and the +NAO, it could mean nothing during the transition.

 

3. If everything works out, it is also possible that compression of waves could occur with this pattern producing a suppressed or weak storm.

 

So, this is not by any means something legit, and I've seen better signals than this.

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00z GFS brings home the best case outcome for early DEC before the transition back normal Nino DEC torch. Second cold push deeper and further east days 10-12. Low then rides northeast up the coast along boundary. Nice snow event in la la land.

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00z GFS brings home the best case outcome for early DEC before the transition back normal Nino DEC torch. Second cold push deeper and further east days 10-12. Low then rides northeast up the coast along boundary. Nice snow event in la la land.

 

Yes it looks like a window cracked open vs no windows at all on that side of the house.

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00z GFS brings home the best case outcome for early DEC before the transition back normal Nino DEC torch. Second cold push deeper and further east days 10-12. Low then rides northeast up the coast along boundary. Nice snow event in la la land.

 

 

Yes it looks like a window cracked open vs no windows at all on that side of the house.

EPS Snowfall mean and indiv members show the potential as well in the first week of december.

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BTW, talk about a difference in ensembles. GEFS have a ----epo, while the EPS have a ++++epo. Also GEFS park the pv over baffin island and with a good amount of positive hgt anomalies across the pole also helping to push the pv south.  While the eps don't have this and continue with trof in alaska flooding canada with warm air.  There is some cold air leftover from the -epo it had but that probabkly would get flushed out fast with the pac flow. 

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BTW, talk about a difference in ensembles. GEFS have a ----epo, while the EPS have a ++++epo. Also GEFS park the pv over baffin island and with a good amount of positive hgt anomalies across the pole also helping to push the pv south. While the eps don't have this. But on the GEFS the +++nao may not help deliver cold despite the -epo

 

This is welcome back to last winter even with the pv spending some time around Baffin Island.  Its all about the amplitude.

 

post-27-0-02050200-1447945438.png

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This is welcome back to last winter even with the pv spending some time around Baffin Island.  Its all about the amplitude.

 

attachicon.gifqLNp1YUNsw.png

Yea, the GEFS pattern is for sure better because at least canada is cold, but I'm not sure I trust them. EPS would flood everywhere with pac air with that pig over alaska.

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Yea, the GEFS pattern is for sure better because at least canada is cold, but I'm not sure I trust them. EPS would flood everywhere with pac air with that pig over alaska.

 

Yes, the GEFS mean has had a much higher skill score/correlation coefficient at day 10 for the NAO (.76) than for the PNA (.57).  I dont have a skill score for the EPO.  On the other hand, the ERSL is still outlooking a pretty healthy -epo. 

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Just not sure how cold this pattern is. The 6z GEFS back off a little on the -epo signature in the long run that the 0z had, but it still has some higher hgts there. Just not sure how cold this pattern would be. You can see there is trofing over the east but it looks like the flow is off the pacific. You can see the southern stream is cutting underneath.

post-1-0-09054700-1447946081.png

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Just not sure how cold this pattern is. The 6z GEFS back off a little on the -epo signature in the long run that the 0z had, but it still has some higher hgts there. Just not sure how cold this pattern would be. You can see there is trofing over the east but it looks like the flow is off the pacific. You can see the southern stream is cutting underneath.

 

Yes, I just follow the contouring over us westward, it enters NOAM in Oregon. Tough to get sustained cold with that.  Need it to be coming in from Canada, even lower BC would do.

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Yes, I just follow the contouring over us westward, it enters NOAM in Oregon. Tough to get sustained cold with that.  Need it to be coming in from Canada, even lower BC would do.

that's what i figured,but in that timeframe if you look at the 850 anomalies, it's not really a warm look and by the end of the run below normal 85o temps dominate much of the east. I would assume maybe that is because of the model trying to pin point a storm somewhere?

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BTW, talk about a difference in ensembles. GEFS have a ----epo, while the EPS have a ++++epo. Also GEFS park the pv over baffin island and with a good amount of positive hgt anomalies across the pole also helping to push the pv south. While the eps don't have this and continue with trof in alaska flooding canada with warm air. There is some cold air leftover from the -epo it had but that probabkly would get flushed out fast with the pac flow.

I'd side with the eps on that. Probably a brief period of an EPO block, but nothing long term. December Nino is your best odds, roll with them.

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that's what i figured,but in that timeframe if you look at the 850 anomalies, it's not really a warm look and by the end of the run below normal 85o temps dominate much of the east. I would assume maybe that is because of the model trying to pin point a storm somewhere?

 

I dont know. I havent looked if CPC 6-10, 8-14 had some wet day analogs in it regardless if it snowed or not.  I would tend to go with the Ecmwf ensembles with the epo/pna and GFS ensembles with the nao, not that either can't be wrong.

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