NittanyWx

46 minutes ago, EasternLI said:

I'd be cautious of those RMM charts if I were you...

I say this every year and no one ever listens.

Hard to dislodge this Aleutian piece balance of Dec.  Threading the needle difficult as PNA dives and lack of source air.  It's very hard to get E Canada HP in a pattern like this.

Think this takes a bit of time to unwind.  

40 minutes ago, Brian5671 said:

Seattle goes into the deep freeze next week that's where all the cold air is going with the -PNA.  We end up with stale cold and battling the SE ridge from time to time for the next 7 days or so.  

For me it's more a matter of if you can leak some air east behind one of these storms, have some HP and can get a little SW riding the boundary between the antecedent airmass and that ridge.

That's how you thread the needle in this type of pattern.  It's a tougher ask.

1 hour ago, MJO812 said:

Alot of redevelopers in in east with the negative NAO

I've read this 3x and I still don't know what you're trying to say.

Not loving these west/Pac trends last few runs.   Path of least resistance is to dump this cold air supply west, makes for a trickier situation if we can bleed something east storm wise. 

The big issue with P 7-8-1 in healthy Nina's like this is the tendency for subsidence over CPac.  It's a seasonal standing wave issue

Well that GOA ridge didnt last long on the EC Ens...

40 minutes ago, EasternLI said:

Happy new year from the 12Z EPS 

You'd want that GOA ridge to nudge east a bit more to really dislodge that cement, but if it can hold onto this for a few runs it would at least be a step in the right direction 

14 minutes ago, MJO812 said:

The AO and NAO arent going to help ?

Neither of those dislodge a decent source airmass into eastern Canada when the Pacific looks like it does.   Tuesday a great example..you get a coastal low with no air and no HP. 

Storms can happen in these patterns, but it's a thread the needle situation and those generally don't work out well for this area.

2 hours ago, jm1220 said:

I’d certainly want to see the PNA at least trend toward neutral for our area. Otherwise I agree we risk another 07-08 with rounds of SWFEs that blast I-90 and do us no good. The SE ridge is beneficial though (not overwhelming) since it forces the storms to turn north and not suppress out to sea. 

The problem is the 2 sigma block sitting over the Aleutians instead of the GOA.  That's driving the PNA tank.

Once again the American suite overamped the VP signal in an area where standing wave/seasonal interference during well developed Nina's occur, got people to bite on it, then backed off on the signal closer in.  I've lost count how many times I've seen the American suite do that.

If the Pacific isn't gonna help at all its gonna be a struggle. 

On 2/24/2020 at 5:54 PM, snowman19 said:

The large area of 90+ degree SSTs north of Australia with convection firing over it back in November should have been a huge red flag that the entire global heat budget and wavetrain forcing was going to get altered in a very big way. The same thing happened back in 2015-2016 with the super El Niño, when ENSO region 3.4 hit +3.1C at the end of November and certain people were still using 57-58, 02-03, and 09-10 as “analogs” and forecasting a very cold and snowy winter in the east because the super nino was more “west-based” than 97-98.....

Right, but it's more obvious when it shows up, but I didn't react until I saw it.  What I'm saying is that there should have been people identifying that risk ahead of time, before the rapid warm-up in early November instead of seeing it in Dec and going 'oh crap'.

On 2/20/2020 at 12:15 PM, Brian5671 said:

LR forecasting is difficult at best.   Look at the super strong PV this year plus the warm water north of Australia-both were late breaking events that helped cause us to be warm and snowless.   Good luck seeing something like that more than a month out....

I think the Australia situation was one where people weren't paying attention or connecting the dots in retrospect.  I don't think a lot of people, at least here in the states anyway, look that closely at Australia to see whether the rainy season advancement was delayed or not.  Once it was clear that was going to happen and solar radiation was going to be much higher than usual at a time when the IOD was collapsing, in retrospect that was a big flag that we should have seen coming.  Even as someone who had a mild winter forecasted, I wasn't nearly warm enough and I think it's because I was too slow to the draw on recognizing that piece and wave train alteration accordingly.

After the record positive Arctic Oscillation print of last week, we now are > +2sigma zonal wind anomaly at 10mb.  PV is an absolute beast this year.

19 minutes ago, bluewave said:

We continue to see the 240hr SE ridge correct stronger than the 360hr forecast.

 

500mb model bias has been way too aggressive with heights in the GOA/AK region all season.  Happened again.

20 hours ago, Allsnow said:

Great post. The only issue I have is that we really haven’t had a coherent wave in the cold phases since November. From the start of  December it has been all warm phases and movement into 7/8 has been to weak. The pv position and strength has played huge role in this disaster. Just a lot went wrong between the pv and mjo. 
 

We did have a coherent wave into the cold phases back in Nov 2019. That was a big reason why that month was so cold. 

See this is where I'm disagree.  I really am not a fan of using RMM plots when I can observe OLR/VPA data in real time.  This was our mid-Jan period.  That's about as coherent of a dateline forcing signal as you're gonna get...

And we still couldn't find a way to get durable cold out of this.  Some will argue that it was a bit more biased to SHem forcing due to some tropical activity, but you still had broad lift in the dateline regions and a ton of subsidence in the Maritime Continent.

4 hours ago, MJO812 said:

2nd winter in a row  where meteorologists disregarded the mjo.

Most meteorologists I know did not disregard the MJO.  If anything, the pattern did not mimic the expected outcome when it transitioned to the 'colder phases' this year.  What does that tell you?  If you want to say that maybe the MJO has had more of an IO/warmer phase bias and that bathwater from a slow monsoon advancement north of Australia torpedoed cold chances earlier in winter, that's fine by me. 

But in a year with very little blocking and a strong ass MJO that was coherent thru the colder phases, we still never got durable cold.  When that happens odds are other things going on overwhelmed the typical MJO wave response.  And that again brings us back to the PV...

1 hour ago, WestBabylonWeather said:

I used to look up to that guy in the 90s reading his accuweather blog

 

hes probably saying ice age coming in March. 

He got dragged pretty badly this month.  He had 881 HDD Feb due to something called a Grand Planetary Alignment.  That theory isn't going well.

4 hours ago, Isotherm said:

Re, correlations to snowfall and 2m temperatures, the issue w/ meteorology, as I'm sure you know, is that many of these relationships are indirect and obfuscated by other contemporaneous signals, so finding the elusive direct correlation to snowfall might be quite difficult [although there are many indicators of high utility in my opinion].

Sure, but you know how the thinking goes: 'This looks like more blocking so it's gonna be cold and snowy'.  

On the surface temps though, I've definitely found 1 and 2 month lead-time signals that exhibit a good amount of skill, but there are always competing influences.  Just stating solar cycles and the QBO weren't 2 of them.  Yet, they get a ton of play in the seasonal space in winter.  In reality, the QBO is a much better rainfall anomaly predictor in certain on/off equator deep convective regions.   

On 1/31/2020 at 5:09 PM, Isotherm said:

 

Solar activity and its attendant proxies have significant utility if one recognizes how to employ it. Those who argued solar minimum induced blocking for the present winter did so with incomplete knowledge. Solar forcing can modulate high latitude geopotential heights, but it must be analyzed in concert with other variables, such as the QBO for example. Thus, linear correlations between SSN and NAO values will be unimpressive because there are other variables masking and confounding. There is a false belief that low solar activity is both a necessary and sufficient condition for high latitude blocking, but that isn't veridical. It's a much more complex relationship. I did not think the suppressed solar activity would lead to a -NAO/AO this winter.

Which is fine and all, but neither the QBO nor solar cycles are able to exhibit a statistically significant correlation to snowfall and 2mt.  Which is what makes this whole exercise challenging and makes me really skeptical about how much we can truly use solar cycles for blocking predictability purposes.

IOD, I'm sure will shoulder the blame and your point about solar minimum in concert with other things potentially affecting high latitude blocking is well-taken.  We absolutely should be looking at other things, and I personally was a 'warm' outlier with my seasonal early this year (obviously not this warm) for a host of other reasons.  But one look at stratospheric zonal wind tells me that there's a lot more going on here than people want to believe they understand on the solar/PV modulation piece in isolation.  It's part of the grey area of the science, and I think we get fooled by noise a lot in this field.

On 1/31/2020 at 5:36 PM, Maestrobjwa said:

 

Hello! Visiting from the Mid-ATL forum...We had a similar discussion during the Fall. One theory that was floated was in reference to a "lag" effect (I cannot remember what study was cited)--supposing that sometimes it was the winters after the minimum during which the minimum from the previous year may have affected blocking (for example, the previous solar minimum was listed as ending around December 2008. Of course it wasn't that winter but the following one that had the blocking. Now perhaps someone else may want to chime in on this "lag" theory.

I'm really having a hard time buying it, but I suppose we'll get another data point next winter.  The #1 correlation I see cited by those who believe in solar theory is the NAO correlation, whereby the thought is that the high-latitude blocking over Greenland would be frequent/strong enough to be statistically relevant in peak solar minima years (this year definitely qualifies as a peak minima year).  Those who believe the theory often use Monte Carlo simulations or other methodologies to prove it.  However, I went back and isolated the past 5 peak solar minima years and found that we had just as many cases that were NAO positive as were negative when we average out NDJFM.

My theory is that we've been fooled largely by small sample size, recency bias (08-09) and randomness.  Maybe there's an element of climate change in there too, but I'm coming around more to the idea that it was never really that robust a relationship to begin with.

20 minutes ago, Brian5671 said:

dramatic flip that year....went from torch to freezer in the space of a few days

Had blocking that year, which remains the biggest thing lacking in this pattern.  I'm still a bit taken aback about just how badly the solar minimum ideas failed this year.  Wasn't the biggest believer in them, but this is pretty a spectatular faceplant which I certainly wouldn't have expected.

Just wanted to point out that the models today are setting a new record positive AO when I comb through my dataset.   I think this winter has done a phenomenal job of disproving a lot of analysis on the 'solar minimum' and it's perceived correlation to blocking.  I had my suspicions before this, but this winter is the final straw for me.

6 hours ago, EastonSN+ said:

What I do not get is the sense that once the bad pattern sets in it's all over as in it will not correct to a better pattern in the future. Unless there is something about the upcoming pattern that historically sticks for months?

It could correct to a better pattern in the future, but from my point of view, I don't think that week 2/week 3 period qualifies.  I'm talking about the pattern and view I have confidence in at the moment, which is for that window.   Generally that's what forecasting is.  I didn't say "no snow balance of winter", did i?"

That said, I still like the pieces on the board for the upcoming weekend and think theres a good chance at a significant storm here.  

Synoptically we have some decent pieces in place for next weekend.   This is the 'window' that I think makes the most sense for a chance at a more significant system.   Behind that, I'm not loving the way the pattern sets up.  But these transition periods historically are where I tend to find we get tagged.

Something to track this week before it gets boring again.

Finished 3.75" here.

Other than north shore LI doing a bit better than expected, generally feel good about how the event unfolded relative to expectations.