Winter 2019-2020 Discussion

[ORH_wxman]

17 minutes ago, 40/70 Benchmark said:

That looks like a neutral to even a modestly neg NAO to me...

The positive height anomaly is kind of blah, but that swath of good negative anomalies stretching from the central Atlantic all the way back into the northeast is very classic -NAO response. 

Either way, we'd take it. 

[40/70 Benchmark]

1 minute ago, ORH_wxman said:

The positive height anomaly is kind of blah, but that swath of good negative anomalies stretching from the central Atlantic all the way back into the northeast is very classic -NAO response. 

Either way, we'd take it. 

Yea, which is why I don't agree with it being a replica of the past few seasons...its better, save for March 2018..

[OSUmetstud]

21 minutes ago, ORH_wxman said:

The positive height anomaly is kind of blah, but that swath of good negative anomalies stretching from the central Atlantic all the way back into the northeast is very classic -NAO response. 

Either way, we'd take it. 

The cfs is definitely -nao. The cansips is debatable. It doesnt look like the positive anomalies in northern greenland are affecting the upstream pattern. 

[40/70 Benchmark]

Just now, OSUmetstud said:

The cfs is definitely -nao. The cansips is debatable. It doesnt look like the positive anomalies in northern greenland are affecting the upstream pattern. 

That's why I said neutral to slightly negative.. 

[OSUmetstud]

2 minutes ago, 40/70 Benchmark said:

That's why I said neutral to slightly negative.. 

I dont agree. The strong ridging further south shows that theres no effective blocking response. It looks more like the -epo +nao winters weve seen of late as opposed to the 2000s classic -NAOs. 

[40/70 Benchmark]

5 minutes ago, OSUmetstud said:

I dont agree. The strong ridging further south shows that theres no effective blocking response. It looks more like the -epo +nao winters weve seen of late as opposed to the 2000s classic -NAOs. 

I disagree. There are modest positive anonalies INVO Greeland.

We all agree its a nice look.

[ORH_wxman]

Just now, 40/70 Benchmark said:

I disagree. There are modest positive anonalies INVO Greeland.

We all agree its a nice look.

He's saying those positive anomalies over Greenland have no response to the south and southwest on the cansips. Look at that swath of positive height anomalies across the Atlantic exactly where the negative anomalies are on the cfs. That looks like a positive NAO pattern despite the anomalies over Greenland. So it might technically be negative based on the cpc definition, it actually behaves more like a positive NAO for our downstream sensible wx. 

[OSUmetstud]

3 minutes ago, ORH_wxman said:

He's saying those positive anomalies over Greenland have no response to the south and southwest on the cansips. Look at that swath of positive height anomalies across the Atlantic exactly where the negative anomalies are on the cfs. That looks like a positive NAO pattern despite the anomalies over Greenland. So it might technically be negative based on the cpc definition, it actually behaves more like a positive NAO for our downstream sensible wx. 

The positive anomalies over the eastern namer and west and central atlantic are factored into the nao calculation from cpc anyway. 

[40/70 Benchmark]

9 minutes ago, ORH_wxman said:

He's saying those positive anomalies over Greenland have no response to the south and southwest on the cansips. Look at that swath of positive height anomalies across the Atlantic exactly where the negative anomalies are on the cfs. That looks like a positive NAO pattern despite the anomalies over Greenland. So it might technically be negative based on the cpc definition, it actually behaves more like a positive NAO for our downstream sensible wx. 

No more positive than the anonalies over Greenland. Neutral to slightly negative is my interpretation.

[ORH_wxman]

3 minutes ago, OSUmetstud said:

The positive anomalies over the eastern namer and west and central atlantic are factored into the nao calculation from cpc anyway. 

Yeah. That's actually even more than I thought initially was incorporated down in the Atlantic basin. 

[ORH_wxman]

2 minutes ago, 40/70 Benchmark said:

No more positive than the anonalies over Greenland. Neutral to slightly negative is my interpretation.

Maybe. But that negative height anomaly near Hudson Bay and just east of there counts too. That's part of the domain...so even if you say Greenland cancels out the central Atlantic, Hudson Bay to just south of Baffin Island is going to tip it.

Regardless, the cfs pattern is much more classic for -NAO. 

[40/70 Benchmark]

12 minutes ago, ORH_wxman said:

Maybe. But that negative height anomaly near Hudson Bay and just east of there counts too. That's part of the domain...so even if you say Greenland cancels out the central Atlantic, Hudson Bay to just south of Baffin Island is going to tip it.

Regardless, the cfs pattern is much more classic for -NAO. 

Yea, I'm not saying its classic -NAO.. I am fine with saying neutral.

[40/70 Benchmark]

The CANsips image that Ventrice tweeted def. looks positive NAO. Little discrepancy...

[dryslot]

I think we all can agree that looks like it would snow out of that pattern.............

[Great Snow 1717]

1 hour ago, OSUmetstud said:

I dont agree. The strong ridging further south shows that theres no effective blocking response. It looks more like the -epo +nao winters weve seen of late as opposed to the 2000s classic -NAOs. 

Agree

[OSUmetstud]

Mike V's maps looked more like Tropical Tidbits for the CanSIPS. It does look like the Weatherbell maps have erroneous ridging over central and northern Greenland. Weird.

 

 

[raindancewx]

It's pretty likely that the Canadian Model is really just outputting information and spatial information for coordinates. So it is up to the vendor to determine the basis for the anomaly with the raw information. Just another reason to be wary of models. Same reason all the different SST data has slightly different baselines.

[OSUmetstud]

1 hour ago, raindancewx said:

It's pretty likely that the Canadian Model is really just outputting information and spatial information for coordinates. So it is up to the vendor to determine the basis for the anomaly with the raw information. Just another reason to be wary of models. Same reason all the different SST data has slightly different baselines.

True, at least Tidbits puts where they are getting their baseline, wxbell just posts "anomaly." 

[dendrite]

6 hours ago, OSUmetstud said:

True, at least Tidbits puts where they are getting their baseline, wxbell just posts "anomaly." 

Anyone check Maue's map? I assume he was the creator of that product at wxbell.

[OSUmetstud]

November ECMWF Seasonal is out. +PNA/+NAO pattern. Big difference for December from October forecast with a beatdown of the WAR and lower heights and pressure over eastern North America extending into the central Atlantic. 

[Typhoon Tip]

I've never seen a seasonal -based tendency product pretty much ever signal a predominating negative North Atlantic Oscillation.  I wonder why that is.. I have a lot of science fiction/plausible explanations, but they are as that implies, suppositional. 

Oh, I'm sure there must've been -NAO seasonal outlooks in the past. But by and large that look above - well, for one, it's really just the PNAP,  or "Perennial North American Pattern." 

Not to be mistaken with the PNA. "Pacific North American,"  it's the entire years geometric height mean, then averaged over all years.  The results features an isohypsotic bulge over the terrain of western North America's Rockies, with a shallowing out east over the remainder of the continent. A PV signature ... Baffin Island (~) does also concomitantly result.   History and averages, the PNAP looks a lot like that above.  

The NAO is a stochastic index ... often demonstrating intraweekly time scale variances.  It's very hard to draft up seasonal deviation/expectations because it is [ apparently ] less anchored by global heat-source-sink and R-wave distribution, as much as it is guided up and down in index value by cyclonic traffic. NCEP also admits this readily in their seasonal outlooks.  Speculation, but that doesn't lend well to any seasonal outlook seeing a positive or negative bias... I mean that look above certainly looks positive, but look closer. There is a subtle albeit real ridge curvature there toward Greenland. It may be that the NAO is really just a very relative index - I think there is some truth to that.  I suspect that the forcing from upstream ...which really starts over eastern Asia/WPO and involves the Pacific eddy as the transitive origin, is all so dominating ... the NAO may be negative or positive relative to that, while not necessarily being defined as positive or negative in any momentary scalar value.  That could certainly account for some of the index' obscuring in seasonal outlooks.   I wonder if the NAO can really be forecast at all.  fascinating -

In any case, that look above to me is really only slightly more indicative than "N/S"; though it lands similarly upon the yearly PNAP structure, just in mind's eye ... perhaps with an edge toward amplitude?  So call it a modest +PNAP ... maybe that is all that is needed to through a couple historic cold waves and some storms through the circuit.    

[OSUmetstud]

23 minutes ago, Typhoon Tip said:

I've never seen a seasonal -based tendency product pretty much ever signal a predominating negative North Atlantic Oscillation.  I wonder why that is.. I have a lot of science fiction/plausible explanations, but they are as that implies, suppositional. 

Oh, I'm sure there must've been -NAO seasonal outlooks in the past. But by and large that look above - well, for one, it's really just the PNAP,  or "Perennial North American Pattern." 

Not to be mistaken with the PNA. "Pacific North American,"  it's the entire years geometric height mean, then averaged over all years.  The results features an isohypsotic bulge over the terrain of western North America's Rockies, with a shallowing out east over the remainder of the continent. A PV signature ... Baffin Island (~) does also concomitantly result.   History and averages, the PNAP looks a lot like that above.  

The NAO is a stochastic index ... often demonstrating intraweekly time scale variances.  It's very hard to draft up seasonal deviation/expectations because it is [ apparently ] less anchored by global heat-source-sink and R-wave distribution, as much as it is guided up and down in index value by cyclonic traffic. NCEP also admits this readily in their seasonal outlooks.  Speculation, but that doesn't lend well to any seasonal outlook seeing a positive or negative bias... I mean that look above certainly looks positive, but look closer. There is a subtle albeit real ridge curvature there toward Greenland. It may be that the NAO is really just a very relative index - I think there is some truth to that.  I suspect that the forcing from upstream ...which really starts over eastern Asia/WPO and involves the Pacific eddy as the transitive origin, is all so dominating ... the NAO may be negative or positive relative to that, while not necessarily being defined as positive or negative in any momentary scalar value.  That could certainly account for some of the index' obscuring in seasonal outlooks.   I wonder if the NAO can really be forecast at all.  fascinating -

In any case, that look above to me is really only slightly more indicative than "N/S"; though it lands similarly upon the yearly PNAP structure, just in mind's eye ... perhaps with an edge toward amplitude?  So call it a modest +PNAP ... maybe that is all that is needed to through a couple historic cold waves and some storms through the circuit.    

The UKMET Glosea5 last fall forecasted a fairly strong -NAO for the winter. It didn't verify. But I mean if were just looking for the post-2013 era, the NAO has nearly constantly positive through winter. 

[40/70 Benchmark]

The EURO had a negative NAO last season.

[weathafella]

That pattern is serviceable 

[raindancewx]

Larry Cosgrove is one of the better seasonal forecasters I've seen, and he's got similar storm track frequencies to what I have in mind. For Dec-Mar his map is probably right for temps. For Dec-Feb, my analogs had the entire cold area to the Northwest by like 300-500 miles. March has a strong bias to be cold in the East in low-solar years. My main disagreement with him is December - his analog blend is pretty cold in Nino 4, which is an easy way to get the East cold in December. My snow map had an enhanced area in the NW, the high elevations of the Rockies, and then in the Midwest, like his does. My hunch for the NE was its "everybody gets 35" kind of winter for Boston to Philly, but that's not quite what the data said.

You can see his forecast on his Facebook. https://www.facebook.com/larry.cosgrove

[bkviking]

Isotherms winter forecast is out 

 

[weathafella]

Isotherm going with a ratter south, less so north.

[512high]

4 minutes ago, weathafella said:

Isotherm going with a ratter south, less so north.

wonder if this will change Rays outlook next week.......

[dryslot]

That outlook looked gradient to me similar to last year.

[40/70 Benchmark]

9 hours ago, 512high said:

wonder if this will change Rays outlook next week.......

I normally don't read outlooks before issuning mine.