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December 2019 Med/Long Range Disco


Bob Chill
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2 hours ago, anotherman said:

 

When the NAO does flip it often happens around day 5-10 but people still seem surprised. NWP has very little skill past day 10 with that. When there is a clear signal and the atmospheric base state is in congruence with that then nwp can be somewhat reliable at range. But of course those are also the times seasonal forecasts are easier. But when there are weak or conflicting signals or the base state is incongruent with those signals the long range nwp is useless because in my experience after day 10 they try to revert to whatever they think the base state should be regardless of the pattern. 

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15 minutes ago, C.A.P.E. said:

Yeah as we well know, the "perfect" h5 looks often don't produce. I will take a -AO , a west based -NAO, and a mediocre PAC with a warm neutral/Nino background state and roll with it.

I don’t want a perfect pattern. I just want one that parks a high pressure over southern Quebec lol. As active as it’s been put a high there and let’s roll the dice.

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18 minutes ago, WinterWxLuvr said:

I don’t want a perfect pattern. I just want one that parks a high pressure over southern Quebec lol. As active as it’s been put a high there and let’s roll the dice.

50-50 low under a NA h5 ridge + surface HP beneath the confluence to its W/SW is money.

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54 minutes ago, psuhoffman said:

But when there are weak or conflicting signals or the base state is incongruent with those signals the long range nwp is useless because in my experience after day 10 they try to revert to whatever they think the base state should be regardless of the pattern. 

That is an interesting comment psu. I think we even see this in the EPS at times.

Meanwhile Anthony thinks cold is coming, I am speculating it could be impressive eventually. ( and hopefully stormy ) 

This might have to do with the weakening + IOD, as he and Webb both recently mentioned, an evolving  MJO and the evolution of sub seasonal factors. 

I also see a potentially more Modoki - ish type configuration as well in the Pac. 

 

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Nice to see this .... it appears region 1.2 is cooling ahead of schedule. Of course we all know this region has a lot of volatility. However,  we don't really want to have significant warm anomalies there.   You can also see the slight changes starting in the IOD. 

 

1896F10F-BAE0-4481-A6B3-84A877AF78BA.png.f32b8218e4572fc0559948a613cc6a50.png

 

 

Meanwhile the visualization at an attempt to weaken the IOD / standing wave further. Hopefully it works out, as it would match the seasonal progression. 

 

5A8AAEC2-443C-4270-8042-A5F3477EB333.png

 

 

 

 

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@frd this is just a hunch and I probably won't articulate this well enough although I will try, but one of the things that has me most hopeful right now is that I kind of have the gut feeling we are experiencing the worst pattern winter has to throw at us and yet its muted and not that bad.  We are going through the same basic progression we are used to early season except the results are muted by this years base state fighting back in a positive way imo.  There are some similarities to last year, only this year the MJO was muted and didnt go ape through warm phases.  The background state seems more conducive to blocking episodes either from the EPO side or NAO side.  Last year the pattern did improve, I know it didnt live up to high expectations but we did get a decent amount of snow in January and February.  This year when some of the typical season progression happens and things "improve" along with our climo just getting more favorable...I have a feeling we will get a pretty good pattern at some point.  

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@Bob Chill that crazy ridiculous block on the GFS yesterday is now on the EPS and all other guidance for that matter day 6/7 lol.  Right now the PAC kind of mutes the impact but we shouldn't be shocked if a storm ends up forced under instead in that look. 

ETA:  at the very least we are going to avoid one of the things that is a bad omen...a VERY positive NAO/AO number for December.  It might still come in slightly positive for the month but we wont have some +2 type number and that is good because there are plenty of examples of slightly positive AO/NAO Decembers that flipped negative for January/February...but there are not many examples of extremely positive Decembers that flipped.  The recent developments up top put us into the range where a better second half is way more believable.  

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7 minutes ago, psuhoffman said:

@frd this is just a hunch and I probably won't articulate this well enough although I will try, but one of the things that has me most hopeful right now is that I kind of have the gut feeling we are experiencing the worst pattern winter has to throw at us and yet its muted and not that bad.  We are going through the same basic progression we are used to early season except the results are muted by this years base state fighting back in a positive way imo.  There are some similarities to last year, only this year the MJO was muted and didnt go ape through warm phases.  The background state seems more conducive to blocking episodes either from the EPO side or NAO side.  Last year the pattern did improve, I know it didnt live up to high expectations but we did get a decent amount of snow in January and February.  This year when some of the typical season progression happens and things "improve" along with our climo just getting more favorable...I have a feeling we will get a pretty good pattern at some point.  

and to further your point, last year we had faux NAO projections which really mucked up some good periods (in addition the MJO that liked the #6).

This year we actually have what appears to be legit opps at -NAO, and MJO moving along, which makes the base state much more workable when things line up right.

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21 minutes ago, psuhoffman said:

The background state seems more conducive to blocking episodes either from the EPO side or NAO side. 

This is right on the mark. I love seeing the -NAO action and it would appear the background state is more conducive to wanting to deliver cooler outcomes. 

No wild high amp warm MJO phases that stall, seems more so to a degree normal,  versus last year at this time . 

If we get the Pac to improve things look very interesting indeed.  I myself enjoy seeing the crazy vacillations in the in the vortex. 

The end of the winter might really feature some good Pac periods, contrary to some thoughts out there. Hopefully, blocking continues to show up.  

The vortex is suppose to get stronger soon, but I believe it is natural at this time of the year to be near interim highs.  I would not be a bit surprised to see weakening by mid Jan to benefit  Feb at some point ,and March especially.  Just speculating but the descending QBO should kick in and be a more significant player by Feb. but as you know we are already getting some blocking episodes. 

This was a cool piece of info ( see below )  that I came across on HM's  feed  IO . 

The uncertain part may not be the weakening of the IOD,  but more so how long will the lag effect take to wear off. That is the tricky part. Seems the standing wave had interfered with achieving the best outcomes from the MJO and tropical forcing.  HM thinks that changes moving forward along with a few other mets. 

Things are looking to pick up around here soon. I have a feeling sometime before March 15 th there will be a KU event for the DC to Baltimore area.  It fits the extreme nature of recent weather events and I feel the HL are targeting the Eastern half of the country this winter season.   

2h
 
The N PAC low/+EPO and Scand. look you see seeing in the extended range is actually a classic IO lag. But the next West Pac influence is already underway then.

 

 

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2 minutes ago, psuhoffman said:

@Bob Chill that crazy ridiculous block on the GFS yesterday is now on the EPS and all other guidance for that matter day 6/7 lol.  Right now the PAC kind of mutes the impact but we shouldn't be shocked if a storm ends up forced under instead in that look. 

I'm not down on the longer range at all. Quite the opposite. But I do think (just like you said) it will take time for seasonal shifts to make it less difficult to snow in these parts. I'm not feeling too good about prospects before Christmas though and I do think we're going to end up in a shutout pattern down the line 10 days or so. Probably short lived but long enough to be annoying. That's just my gut feeling.

I can see the "way out" of a shutout just like you outlined. And that could certainly happen. I can't shake the strong gut feeling that the final "bad pac trough" digs deep and scours NA followed by a -EPO spike and cold factory starts again which would mean things may look really good sometime between Christmas and New Years. Just a total WAG but that's what I think will happen right now. 

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18 minutes ago, psuhoffman said:

baby steps, but a step towards the euro, on the GFS

ETA: compared to 0z....forgot to look at 6z

Has a bit of a detached front end WAA piece which is good because it gets precip into the cold airmass. Quick snow and ice thump.

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GFS sniffing the potential down the road    :sled:.......or maybe just tripp'in  :thumbsdown:

I am looking forward t the Euro and EPS run soon. I really feel the block is not figured out yet properly by any model, not to mention the vacillation of the PV near days 7 to 12.  

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11 minutes ago, StantonParkHoya said:

GFS still insistent on the the SLP off the SE coast next weekend

Just to show how futile it is to look at an op that far out in range (even tho I am for kicks and giggles only), you gotta love the 6 closed LP contours off the coast. Take your pick. Again, resolution gets cut at this range but just funny to see. 

gfs_mslp_pcpn_frzn_neus_40.png

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11 minutes ago, StantonParkHoya said:

GFS went from putting down snow on the OBX beaches to raining on us with the same low (12/22) within 2 cycles. lol.

Would you expect anything different 10 days out on an operational model? Pick any random time stamp d10+ on Tropical Tidbits and click "previous run" at least 10 times. It will always be that way. 

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Just now, WinterWxLuvr said:

Man what an active pattern we seem to have heading into prime climo. This keeps up and we may end up with a big winter.

You and I have always said bring on the wet first and then let's see what happens. I've been happy to see the moisture train start back up a few weeks back after the dry stretch.

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1 minute ago, leesburg 04 said:

You and I have always said bring on the wet first and then let's see what happens. I've been happy to see the moisture train start back up a few weeks back after the dry stretch.

If I recall correctly last December was for the most part was dry. I remember not having any issues with my "Longwood Gardens -ish " type Christmas lights out front. This December so far has featured a combo of chilly, cloudy, wet and raw and and a covering of snow. 

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8 minutes ago, frd said:

GEFS does have some hits for our area on 12/21.  

I doubt this cuts. Either it hits, or a Southern slider or OTS. 

Damn, that block, so pretty !  

 

  

gfs-ensemble-all-avg-namer-z500_anom-6951200.png

Any staying power with that block?  Maps not out yet on TT.  Just curious 

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