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December pattern/forecast thread


weathafella

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Exactly!  That's why we can't rule anything out.  Could get very warm?  Could get very cold?  Could have a snowy period like Scott brought up..those are hard to see coming from any lead time.  There have been many nice stretches in not so great/riding the fence set ups over the years.  I think it will be interesting though going forward-not boring anyway.  

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1 minute ago, WinterWolf said:

Exactly!  That's why we can't rule anything out.  Could get very warm?  Could get very cold?  Could have a snowy period like Scott brought up..those are hard to see coming from any lead time.  There have been many nice stretches in not so great/riding the fence set ups over the years.  I think it will be interesting though going forward-not boring anyway.  

Thanks for the pep talk! That made us feel better!!

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3 minutes ago, Typhoon Tip said:

mmm .. i put it at about 70/30 in favor of warm frankly.  

Could be warm and snowy too...we've had patterns sort of like that. Feb 2013 comes to mind...I think it was a fairly warm month in the CONUS overall...we were right around average here, but of course it was a snowy month as well. We typically need some blocking though to make it work.

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5 minutes ago, ORH_wxman said:

Could be warm and snowy too...we've had patterns sort of like that. Feb 2013 comes to mind...I think it was a fairly warm month in the CONUS overall...we were right around average here, but of course it was a snowy month as well. We typically need some blocking though to make it work.

He's prob basing it on EPO going ++

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34 minutes ago, Googlymoogly said:

Can one of the mets indulge me and tell me how torchy Xmas period might get, and the main reasons why? 

Prior to present time ... we were dealt a negative East Pac Oscillation index, which is synonymous with ridging up ivo Alaska at mid and upper levels. 

That flow construct causes N/NW transportation of air masses into western Canada ...these cold plumes then spread out across the remainder of the Canadian and so forth.  

This usually all presages some sort of cooling temperature distribution over the contiguous U.S. given time, as well.   

However, concurrent with that was the preponderant SE ridge ... actually down right interminable it would seem.  Perhaps keyed into the -PNA that's heavily correlated and also was going on ...  

Those two signals are in conflict.  In conflict, at our latitude, cold has a funny way of winning from time to time.  We can get deals like the other day... or, if a high pressure node times better, more of a mix or ice or 'front end loaded' snow storm...etc.   Not always, but it's not a done deal for warmth when the EPO is negative.  

Unfortunately, ...present teleconnectors from the GEF's (American -based model offices) are signaling a rising EPO...flipping the phase entirely positive over just the next week. While these other teleconnectors remain static.  If so, that would mean we are conceptually losing any capacity to 'fend off' the warm signal from the preponderant SE ridge.  In fact, (and this is just my opinion based upon what I have seen...) it would not shock me at all if at some point record warm - however long not withstanding - eventually verified over the next 10 days to two week; with perhaps one or two intervening returns to normal/...maybe somewhat below, in between.

I was just noticing the thickness pattern in the operational GFS is attenuating the gradient look from D 7 or so onward ...may be a physical manifestation of losing the cold loading (+EPO) taking hold. 

 

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4 minutes ago, Damage In Tolland said:

He's prob basing it on EPO going ++

Yes, and it's a good hedge...it is hard to be cold with a +EPO.

 

If the pattern is right though it can still snow up here. '07-'08 spent much of the winter in a +EPO pattern...we did get a stint of -EPO in the first half of December when we cleaned up, but January and Feb were positive and we still had some good snow events...but we also averaged above normal temps in the means.

 

And of course, the EPO could be volatile too...we just don't know how it will change with time. 2008-2009 is an example of wild swings in the EPO...we had bouts of big negative and then huge positive.

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3 hours ago, WinterWolf said:

I wouldn't rule anything out.  Even last years torch winter had the coldest outbreak in years(granted in a sea of warmth), and the biggest blizzard for some areas of the Mid Atlantic of all places, ever...NYC breaks there all time 24 hour snow record in that one.  It isn't all doom and gloom. 

 The problem is last winter, the pattern looked like it would reverse toward a favorable one for January. We had strong wave driving and conducive tropical forcing which aided in perturbation and subsequently NAM decrease. Right now, I don't see much indication of decelerating PNJ given the tropospheric pattern. Wave 1 and 2 will meander within typical standard deviations. Pacific forcing isn't great either. We will retract the jet and attempt to build poleward ridges through wave breaks and QBO modulation, but likely in transient periods. I have more confidence that the Pacific will aid us occasionally, rather than the Atlantic. Further north in much of interior New England, snowfall can occur in a mediocre pattern and largely low arctic heights as well. We shall see how things progress. I certainly wouldnt be worried in most of New england away from the coast. But the pattern isn't a good one for the coastal plain in general.

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41 minutes ago, Isotherm said:

 The problem is last winter, the pattern looked like it would reverse toward a favorable one for January. We had strong wave driving and conducive tropical forcing which aided in perturbation and subsequently NAM decrease. Right now, I don't see much indication of decelerating PNJ given the tropospheric pattern. Wave 1 and 2 will meander within typical standard deviations. Pacific forcing isn't great either. We will retract the jet and attempt to build poleward ridges through wave breaks and QBO modulation, but likely in transient periods. I have more confidence that the Pacific will aid us occasionally, rather than the Atlantic. Further north in much of interior New England, snowfall can occur in a mediocre pattern and largely low arctic heights as well. We shall see how things progress. I certainly wouldnt be worried in most of New england away from the coast. But the pattern isn't a good one for the coastal plain in general.

there's nothing there I would disagree with -

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Could be warm and snowy too...we've had patterns sort of like that. Feb 2013 comes to mind...I think it was a fairly warm month in the CONUS overall...we were right around average here, but of course it was a snowy month as well. We typically need some blocking though to make it work.


This...this is what I was referring to in regards to getting storms and snow in a less than favourable pattern.
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The split flow and the Scandanavian Ridge should save nne and Atlantic Canada from a complete disaster but the pacific is pretty bad. 


Is that what is causing the weird storm track where the lows are riding up into St. Lawerence valley and then shunting off either over NS or just south at the last second?
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1 hour ago, Hazey said:


Is that what is causing the weird storm track where the lows are riding up into St. Lawerence valley and then shunting off either over NS or just south at the last second?

No im talking about the christmas period. Right now we just have really fast confluent flow with lots of cold around because of the big Ak ridge is about to go bye bye.

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27 minutes ago, Hazey said:


Ok fair enough. Looks like you'll have a nice pack before any torch comes through.

Looks like New Glasgow Nova Scotia will have a good snow pack too before any warmth comes through. I heard that their is a 50-50 chance of a white christmas for Halifax, and a higher chance as you go North this year.

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