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Winter 2014-2015 Thread


Ji

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I have to give a presentation to the DC Council on 10/27 and I am still pretty confused...I will probably just end up hedging, and going climo, and be nebulous....I guess for now, I still like my call of 0 to +1 and slightly north of median snow

 

Give them -2 and -3 and 400% snow just to get their reaction. :snowing:

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This is a really important post. Appreciate it.  I don't think many people realize that the GOA was cold this time last year. 

 

anomnight.10.7.2013.gif

 

It really didn't start to look anomalous until late December. I totally agree about the region being more of a byproduct of the pattern vs a driver. I suppose once things are ripe it could potentially feedback into persistence but I'll defer there. 

 

Watching the npac sst config evolve is a pretty good tool for finding clues about persistence. Right now the npac in general has been under assault with storms and BN temps. Running the loop for the last 6 weeks is very telling. The region in general will almost certainly continue to cool for at least another week and then it looks like the GOA will continue beyond that. 

 

All of this is fine in my book. At the very least, the clues I'm seeing right now support the possibility of a +pdo during the start of winter. Mixed signals on the ensembles down the line irt the aleutian low showing as strong signal on the monthly mean. Even if it does because we are off to such a strong start, if it starts getting erased because of stubborn ridging in the same area  later this month it would be a net negative in the grand scheme.

 

Hard to get worked up about anything imo right now considering it's only October. There is nothing hostile staring at any of us in the East. Hopefully it stays that way. 

 

I thought we have been more negative in September than we were...Mantua had us at +0.67 which surprised me a bit.....anyway the PDO region is looking better and better...the whole NPAC along 40N has been cooling..we've had a +PDO all year, .and +PDO in October leads to a +PDO in the winter about 85% of the time....While I am not sure it will be strongly positive, there is no reason to think it will be a -PDO winter

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I have to give a presentation to the DC Council on 10/27 and I am still pretty confused...I will probably just end up hedging, and going climo, and be nebulous....I guess for now, I still like my call of 0 to +1 and slightly north of median snow

It would actually be anomalous for DC to come in at climo for winter.  Feast or famine, it's been.   :whistle:

 

MDstorm

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I'm feeling better and better that we don't sh-it the bed....I don't see any reason to believe the crappy pos neutral/weak nino winters are viable analogs....

More questions than answers. If I was forced to say something definitive I suppose I'm leaning towards short cycle volatility vs a tale of 2 winters (or no winter. lol).

I could easily envision each winter month having some decent cold shots but reprieves in between. Not convinced at all that we get the big stable cold/warm pattern and ride it for 6 weeks.

Snow in the 75%-125% of climo seems reasonable. Snow is such a beast to predict anyways.

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More questions than answers. If I was forced to say something definitive I suppose I'm leaning towards short cycle volatility vs a tale of 2 winters (or no winter. lol).

I could easily envision each winter month having some decent cold shots but reprieves in between. Not convinced at all that we get the big stable cold/warm pattern and ride it for 6 weeks.

Snow in the 75%-125% of climo seems reasonable. Snow is such a beast to predict anyways.

 

 

That's a pretty thick limb you're standing on.

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My only concern right now is that the ridge in Alaska gives in, and gives way to nasty GOA vortex that pumps pacific air into CONUS...everything else looks good to me. Nino is struggling, but I am confident it will positively effect winter as it slowly matures.

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My only concern right now is that the ridge in Alaska gives in, and gives way to nasty GOA vortex that pumps pacific air into CONUS...everything else looks good to me. Nino is struggling, but I am confident it will positively effect winter as it slowly matures.

that made me think about some of the posters here    lol

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I know better than to make a definitive snow call months in advance. It's best to wait until after the season is over.

My armchair guess is no disaster or shovelfest. That's all I got.

If I had to make a snowfall prediction with no scientific backing, I would say slightly above average snow. Maybe 130%? So that would place DC around 20"... if I remembered their average correctly.

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If I had to make a snowfall prediction with no scientific backing, I would say slightly above average snow. Maybe 130%? So that would place DC around 20"... if I remembered their average correctly.

I could easily see that happening. I could also see 10" while IAD/BWI fare much better. I don't think any reasonable # can be laid out with any confidence. Seems like things are lining up for some ok periods and not wall to wall suicide watch. That can change of course.

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I could easily see that happening. I could also see 10" while IAD/BWI fare much better. I don't think any reasonable # can be laid out with any confidence. Seems like things are lining up for some ok periods and not wall to wall suicide watch. That can change of course.

How often do you guys have back to back great winters? I am sure you guys have had them.

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How often do you guys have back to back great winters? I am sure you guys have had them.

86-87/87-88 was the last DC climo+. But there was a freak storm in Nov that kinda skews that. Without that storm the 87-88 winter was "ok" but not great.

81-82/82-83 were pretty good together. Overall the stretch from 77-78 through 87-88 made DC look like a snow town. The 60's were great overall. I've personally wondered how much the AMO has to do with it. The -amo period from 1960-1990 contains an awful lot of good winters. When it flipped + snowfall kinda tanked year over year. The only thing keeping us up on the averages are 4 really big winters in the last 25 years.

ETA:

The 40's and 50's weren't good at all here. Especially considering snowfall was measured at a better location. These decades were during a +amo period. I don't know enough about it to say much more than it seems like decent snow periods correlate better to a -amo than +amo.

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http://theweathercentre.blogspot.com/2014/10/historically-accurate-pattern-predictor.html

 

Interesting... I don't know why it would be called  "OPI Index" when all it does is predict the state of the AO. The name implies that it can predict the overall pattern, which, the AO alone cannot do.

My unhelpful post!

post-1604-0-77676000-1412800681_thumb.jp

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86-87/87-88 was the last DC climo+. But there was a freak storm in Nov that kinda skews that. Without that storm the 87-88 winter was "ok" but not great.

81-82/82-83 were pretty good together. Overall the stretch from 77-78 through 87-88 made DC look like a snow town. The 60's were great overall. I've personally wondered how much the AMO has to do with it. The -amo period from 1960-1990 contains an awful lot of good winters. When it flipped + snowfall kinda tanked year over year. The only thing keeping us up on the averages are 4 really big winters in the last 25 years.

ETA:

The 40's and 50's weren't good at all here. Especially considering snowfall was measured at a better location. These decades were during a +amo period. I don't know enough about it to say much more than it seems like decent snow periods correlate better to a -amo than +amo.

We are the same....a return to the that period would be nice. The question is has the upturn started as of 09/10 or are we going to suck wind a few more seasons and it doesn't start until end of this decade or even longer.

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We are the same....a return to the that period would be nice. The question is has the upturn started as of 09/10 or are we going to suck wind a few more seasons and it doesn't start until end of this decade or even longer.

I don't think it started but I surely don't know enough about the topic to be taken seriously. It seems like we in fading stage of the + period still. Seems like the neutral years have been good recently. Unfortunately the index has moved up the last 3-4 months so I don't think we can look to it for help or insight for the upcoming winter.

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First week of the month looks pretty good and the anomaly near the Aleutians will grow in strength over the week. Trends have been steadfast in moving the lowest height anoms in the GOA region down the line but the big aleutian ridge idea is fading. The area will ridge out for a time but it looks brief. Ensembles are becoming pretty flat in d10-15 so that period is pretty muddy. Probably a result of timing on the various members. Looks active and progressive in the region from what I can tell. Which is fine. As long as a ridge doesn't anchor itself we will almost certainly have a good look on the means for the month. 

 

post-2035-0-14949100-1412863984_thumb.gi

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First week of the month looks pretty good and the anomaly near the Aleutians will grow in strength over the week. Trends have been steadfast in moving the lowest height anoms in the GOA region down the line but the big aleutian ridge idea is fading. The area will ridge out for a time but it looks brief. Ensembles are becoming pretty flat in d10-15 so that period is pretty muddy. Probably a result of timing on the various members. Looks active and progressive in the region from what I can tell. Which is fine. As long as a ridge doesn't anchor itself we will almost certainly have a good look on the means for the month. 

 

attachicon.gifOct 1-7.GIF

 

I thought a Alaskan ridge would be beneficial even with a Aleutian low?

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I thought a Alaskan ridge would be beneficial even with a Aleutian low?

 

We don't want a ridge where the current neg anomaly has built up. It typically means that downstream there is a low in GOA acting as a pac air pump into the conus. 

 

Ridging above the low anomaly is totally fine and expected most of the time. Move that ridge south and we are in trouble more often than not. 

 

There's also a big difference between oct and winter months. Matt posted a killer composite on how most of our above climo winters featured an aleutian low in Oct. 

 

It's also a common feature during nino's. Even though we aren't in a nino, the atmosphere appears to be acting like we are right now. 

 

The current pattern we are in would be pretty darn good if it was met winter. If we see it again when it really matters is anyone's guess. 

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We don't want a ridge where the current neg anomaly has built up. It typically means that downstream there is a low in GOA acting as a pac air pump into the conus. 

 

Ridging above the low anomaly is totally fine and expected most of the time. Move that ridge south and we are in trouble more often than not. 

 

There's also a big difference between oct and winter months. Matt posted a killer composite on how most of our above climo winters featured an aleutian low in Oct. 

 

It's also a common feature during nino's. Even though we aren't in a nino, the atmosphere appears to be acting like we are right now. 

 

I see, thanks for clarifying. I was under the impression that with a decent ridge in Alaska, even with a Aleutian low and +PDO, cold air would become more common in CONUS. I have to look into this further..

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I see, thanks for clarifying. I was under the impression that with a decent ridge in Alaska, even with a Aleutian low and +PDO, cold air would become more common in CONUS. I have to look into this further..

 

even if we remove the years that had a formidable nino at this point, the composite of 20"+ winters had an aleutian low in october...this is all related to what the OPI thread is about, and what Hart was doing years ago with his NPAC index based on his own dataset

 

post-66-0-50331000-1412873404_thumb.png

 

Here is the composite of the big winter ninos that were already happening in those octobers...the low is south of the aleutians (where we want it this winter), but this features is already pretty nino driven

 

post-66-0-71160500-1412873657_thumb.png

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