December pattern/forecast thread

[dryslot]

I had to go look after seeing some of the post, I still think things look ok, Even if we have to take another cutter or so

[CoastalWx]

8 minutes ago, dryslot said:

I had to go look after seeing some of the post, I still think things look ok, Even if we have to take another cutter or so

Typical transition.  What looks good 8 days out doesn't always come to fruition and people get bummed. That's the risk of being 7-8 days out. Next week still needs to be watched for interior and NNE.

[dryslot]

4 minutes ago, CoastalWx said:

Typical transition.  What looks good 8 days out doesn't always come to fruition and people get bummed. That's the risk of being 7-8 days out. Next week still needs to be watched for interior and NNE.

I agree with you on next week, I know some expect it to be like a light switch you just flip it off or on and its full blown winter, Its a step down process and after last Dec, At least there is more of a chance that it gets wintry this year,  But as evident here today, We were already suppose to be above freezing but the cold hangs on longer then modeled and we have zr falling with temps at 29°F

[ORH_wxman]

Usually at this stage of the season, there's some that want to talk in the same way we talk when snow threats are 3-4 days out. Unfortunately we can't do that. 

 

I would say the best thing about guidance right now is the monster WPO ridge. That's going to make this December at least in contention unlike the past two. 

[40/70 Benchmark]

2 hours ago, Ginx snewx said:

I suppose we could play the waffle game and throw out caution flags to make it legit. 

 

It might be cold or it may not. Ya know tropical forcing and the MJO might or might not play a role but I will wait until the next model run comes out. I mean it looks good until it doesn't then when it doesn't I can say I told you so 

 

We could....but I'd rather not bite on the single most threatening suite of guidance, until some measure of consistency is achieved.

[40/70 Benchmark]

22 minutes ago, ORH_wxman said:

Usually at this stage of the season, there's some that want to talk in the same way we talk when snow threats are 3-4 days out. Unfortunately we can't do that. 

 

I would say the best thing about guidance right now is the monster WPO ridge. That's going to make this December at least in contention unlike the past two. 

It looks like a normal month to me....which isn't to speak in absolutes because that idea could prove wrong.

But there seems to be this natural proclivity for folks to want to polarize concepts, and accordingly label ideas as dismissive of guidance supportive of more extreme solutions. 

Its paradoxical in the sense that if anything, they should be doing the exact opposite until very short lead times.

Think bell curve, people.

[Damage In Tolland]

Any concern about the massive SE ridge on the GEFS and the AO not going negative? It's hard when we are depending on the EPS only

[Typhoon Tip]

1 hour ago, ORH_wxman said:

I would say the best thing about guidance right now is the monster WPO ridge. That's going to make this December at least in contention unlike the past two. 

It's showing up in the low level wind flux anomalies as shown here:

ftp://ftp.cdc.noaa.gov/Public/gbates/reforecast2/teleconn/4indices.png

I'd like to see the CPC method for computing the teleconnectors on that, too - unfortunately, as far as I can find ...there are no agencies on this side of the pond that compute the Pacific quadratures - the CPC only does the PNA.   The EPO and WPO, I've always had to rely on the Climate Diagnostic Center's postings. 

It makes a difference because ... the CDC (as hinted above) relies on lower lever wind anomalies to infer the indexes; contrasting, the CPC uses mid-level geopotential height anomalies.  

I think that matters, seasonally.  In the summer, the wind fluxes may be more pertinent, but in the winter?  The winds/jets are maxing everywhere and the stretching wave lengths that lock in as a physical response means that the geopotential anomalies would be more telling.  

'Course, then there's the EPS -based products; which I have no idea if they even disseminate actual quantized predictions of these different mass-fields.  Like ...is there an ECM ensemble -based West Pacific Oscillation?  EPO for that matter... PNA, ...NAO... etc, etc.  No idea. I don't want to pay for their products because frankly... I find that subtleties in trends and so forth, re the GEFs -based products, do just fine.  I've pulled more D12 plausibilities out of the ether based on the GEFs than I can count, and the Euro..heh, was always there waiting in the wings for when x-y-z event came into the mid ranges of lore. 

Anyway, the WPO as show above is going negative and the 'tonality' of the depiction looks clad and steady - not spiked and returning positive. Meanwhile, the EPO doesn't seem as interested...though is slipping some. It may be that the EPO's domain space is being 'stressed'/influenced by the physical presence of the WPO's wave spacing decaying downstream.  If that's the case, the EPO may not really be the 'type' of negative folks want it to be. But I agree in principle; if the WPO gets strongly negative eventually the Pacific's northern arc should enter the AB phase --> -EPO surely follows. 

When? 

heh. right.  Frankly, the 00z operational versions tell us to pull the shades and/or find different hobbies until further notice.  Man, they slipped right back into a persistence wrt the SE ridge anomaly.  Actually, in fairness, I think the GFS has been demonstrating good consistency et al. The Dec 5 thing that Euro tried to sell yesterday understandably dumped that idea about as fast as it was snowing in the previous run ...one would expect the southern component to shear/damp as it ran into that height wall.  No shocker there... I was mentioning that to Scott or someone yesterday that the SE ridge's presence really needs to be deconstructed before (personally) biting into much any middle/extended range.  The correction vector is always pointed toward negative interference until that happens. I don't think that feature is immovable... whatever is back-building it's existence is obviously connected to some systemic thing down stream from who-knows-what.  

Prior to mid level waves being ejected out of the west, if the heights over Miami are above 582 decameters and/or the balanced geostrophic wind is above 35 kts, it's a game of how much does said wave get eaten alive.   

[CT Rain]

38 minutes ago, Damage In Tolland said:

Any concern about the massive SE ridge on the GEFS and the AO not going negative? It's hard when we are depending on the EPS only

Looks like the PV is about to strengthen quite a bit in the D8-D15 range. I would not count on any -AO in the near future.

[WEATHERBUFF]

41 minutes ago, Damage In Tolland said:

Any concern about the massive SE ridge on the GEFS and the AO not going negative? It's hard when we are depending on the EPS only

gfs has been horrible, rather have the euro

[J Paul Gordon]

The link Tip gave seems to show things moving in a less than positive direction. -PNA (and getting more so), -NAO getting less so. I'm not familiar enough with the WPO and EPO to even begin to understand how they play.

Question is, are things moving toward a warmer, zonal flow, SE Ridge solution, or, is it all (literally) still up in the air?

[masonwoods]

50 minutes ago, Damage In Tolland said:

Any concern about the massive SE ridge on the GEFS and the AO not going negative? It's hard when we are depending on the EPS only

You should read Dr. Cohen's Blog.  He provides updates every Monday.

http://www.aer.com/science-research/climate-weather/arctic-oscillation

[ORH_wxman]

7 minutes ago, J Paul Gordon said:

The link Tip gave seems to show things moving in a less than positive direction. -PNA (and getting more so), -NAO getting less so. I'm not familiar enough with the WPO and EPO to even begin to understand how they play.

Question is, are things moving toward a warmer, zonal flow, SE Ridge solution, or, is it all (literally) still up in the air?

 

The WPO/EPO numbers are good...that is what we want to see. Having them negative increases cold in the northern tier...it's basically just telling us that there is cross-polar flow into Canada and that drains into the CONUS. The strongly negative PNA is helping pump the SE ridge up for next week, but it relaxes further out in time....and a -PNA itself isn't terrible for New England...it's far worse for the Mid-Atlantic. Some of our biggest Decembers have come during a -PNA regime. The thing is, with that type of pattern, you want impulses ejecting out of the western trough in pieces and not one huge shortwave...the latter makes a cutter more likely. Having pieces of energy eject makes an overrunning or SWFE more likely.

 

We're also at the whim of what is going on in SE Canada...you can have good confluence there to lock in a strong high to the north of Maine, but if you don't have that, then you will quickly flip to plain rain and it will be easier for any surface low to pass NW of us.

[CoastalWx]

5 minutes ago, J Paul Gordon said:

The link Tip gave seems to show things moving in a less than positive direction. -PNA (and getting more so), -NAO getting less so. I'm not familiar enough with the WPO and EPO to even begin to understand how they play.

Question is, are things moving toward a warmer, zonal flow, SE Ridge solution, or, is it all (literally) still up in the air?

It's moving into a typical Nina state with tropical convection in the Indonesia area forcing a big Bering Sea ridge and downstream trough in western NAMR. As is usually the case in these patterns, the battle ground is close by. Now when 50-100 miles means the difference between rain and an all out snow blitz.....that's something impossible to determine.  However, it's probably the best look we've seen in a while for the month of December. I'd role with that look.

[qg_omega]

18 minutes ago, CT Rain said:

Looks like the PV is about to strengthen quite a bit in the D8-D15 range. I would not count on any -AO in the near future.

directly related to recent uptick in solar activity.  

AN UPTICK IN SOLAR FLARE ACTIVITY: Two new sunspots are rapidly emerging on the solar disk, and one of them is crackling with B- and C-class solar flares. So far the eruptions are minor. However, they do represent a noteable uptick in activity compared to the absolute quiet of recent months. 
 

From speacweather

[J Paul Gordon]

Thank you mets for your response. I have a better sense of the larger picture. And, as you both said, it's looking a lot better than the past two Decembers. I had thought a -PNA was a disaster for SNE. I'm glad you clarified that it is not (necessarily) the case. Is this a north of 40N vs south type of thing?

[Ginx snewx]

AO is neutral for the foreseeable future on the latests GEFS  EPS and yes EPS has charts on all telles Tip

[Allsnow]

We probably run the risk of two more cutter next week before we see more of a favorable pattern. The EPS shows the mean trough moving towards the central plains around the 8th. We will probably have another big cutter just before that. That day 8-15 looks pretty good on the EPS. 

[ORH_wxman]

1 minute ago, J Paul Gordon said:

Thank you mets for your response. I have a better sense of the larger picture. And, as you both said, it's looking a lot better than the past two Decembers. I had thought a -PNA was a disaster for SNE. I'm glad you clarified that it is not (necessarily) the case. Is this a north of 40N vs south type of thing?

 

There's no set latitude line where it's fine north and horrible south...it just gets progressively worse as you go south of New England.

 

 

 

[CoastalWx]

Don't forget that these patterns really seem to get much more useful near mid December. That's when climo helps and you establish a nice snowpack in Canada to keep the source cold.  a 1040 high in Quebec is definitely more useful over the interior when there is snow at the source region. So, take the setup you see now and add two more weeks....likely a more wintry outcome.  What may be IP and ZR to rain now, could be SN to ice later.

[dmillz25]

5 minutes ago, ORH_wxman said:

 

There's no set latitude line where it's fine north and horrible south...it just gets progressively worse as you go south of New England.

 

 

 

Yup one of those things where BOS could luck out, NYC is on the edge and PHl on south suffers

[ORH_wxman]

3 minutes ago, CoastalWx said:

Don't forget that these patterns really seem to get much more useful near mid December. That's when climo helps and you establish a nice snowpack in Canada to keep the source cold.  a 1040 high in Quebec is definitely more useful over the interior when there is snow at the source region. So, take the setup you see now and add two more weeks....likely a more wintry outcome.  What may be IP and ZR to rain now, could be SN to ice later.

 

It matches our SWFE climo pretty well when you look at the December events over the years...whether it's Dec 1970, Dec 1975, Dec 2007 or 2008...the fun tends to begin after the 10th.

Typically before that, we need something fully underneath us at 5H...ala 12/9/05 or one of the Dec 5th events from 2002 or 2003. We could still get that around Dec 5 this year, but it's an uphill battle.

[Damage In Tolland]

Was it the GEFS or EPS last winter that kept insisting winter was coming? 

[CoastalWx]

1 minute ago, Damage In Tolland said:

Was it the GEFS or EPS last winter that kept insisting winter was coming? 

This is nothing like last December. Not even close. The hemispheric pattern is night and day. Our horrible winters and Decembers for that matter, usually have a crappy pattern to a good chunk of the US and srn Canada. This is nothing like that. 

[WinterWolf]

Will and Scott, thank you both so much for some fabulous posts and info.  Very well put, and easy to understand!!  This, like some were eluding to, will take some time to establish itself, but the look is nothing like last December as you both pointed out.  And we should feel some sense of relief for that alone, and that the pattern going forward at leasts affords us the chance at some type of Wintry events...as you both put it:  We'll all role the dice in this upcoming pattern and take our stabs!!

 

Thanks again.

[J Paul Gordon]

P.S. I'm not real sure about names around here. Do we have a list of folks actual names vs. posting ids?

I'm J Paul--just like my profile says. 

[MJO812]

GEFS looks a lot better than the op run moving forward

[40/70 Benchmark]

29 minutes ago, J Paul Gordon said:

P.S. I'm not real sure about names around here. Do we have a list of folks actual names vs. posting ids?

I'm J Paul--just like my profile says. 

I'm Ray, Paul..

[ORH_wxman]

The 12z GGEM sort of shows you how things could stay on the cold side next week...it's all about the timing of the shortwaves. It's why we shouldn't get into the habit of saying things like "the cold is locked in" or "we're locked into a cutter next week"....with good cold lurking to the north but a deep trough out west at the same time, it's never a good idea to lock stuff in. You can go either way.

FWIW....time sensitive:

http://mp1.met.psu.edu/~fxg1/CMCNA_12z/cmcloop.html

 

I do think the deeper cold will be more prevalent after about Dec 9-10 or so...but there's still enough cold lurking before that to not rule anything out.

[CT Rain]

Euro caves to GFS on Monday storm.