February 2025 Disco/Obs Thread

[mahk_webstah]

According to Wpc map the primary has come back to western pa.  This is what Will said needed to happen

[40/70 Benchmark]

5 minutes ago, CoastalWx said:

You guys might be ok, it's just more dicey down here.

Yea, he will probably have a net gainer and I may even...just saying I don't see it as a KU.

[CoastalWx]

Just now, Cold Miser said:

This would be Steve's "Big Dog" that he has been talking about?

Possibly. 

[40/70 Benchmark]

2 minutes ago, CoastalWx said:

Possibly. 

That is the window...after this weekend.

[mahk_webstah]

4 minutes ago, 40/70 Benchmark said:

Yea, he will probably have a net gainer and I may even...just saying I don't see it as a KU.

The KU comes next week I’d think.  Well, at least a pattern that has a strong chance to produce one. That could be the one where we are on the fringes up here.  In the meantime, we just pile it up. I’m glad you did well yesterday! My brother-in-law lives in East Derry and they got like 10 inches so there was a nice jackpot down in that general direction.
 

[40/70 Benchmark]

1 minute ago, mahk_webstah said:

The KU comes next week I’d think.  Well, at least a pattern that has a strong chance to produce one. That could be the one where we are on the fringes up here.  In the meantime, we just pile it up. I’m glad you did well yesterday! My brother-in-law lives in East Derry and they got like 10 inches so there was a nice jackpot down in that general direction.
 

The piles along my driveway are like 4-5'.

[mahk_webstah]

Just now, 40/70 Benchmark said:

The piles along my driveway are like 4-5'.

Feels great eh?  You might be far enough north and inland to get a few inches on Thursday.

[40/70 Benchmark]

8 minutes ago, mahk_webstah said:

According to Wpc map the primary has come back to western pa.  This is what Will said needed to happen

You should change your handle to wpc lol

[40/70 Benchmark]

Just now, mahk_webstah said:

Feels great eh?  You might be far enough north and inland to get a few inches on Thursday.

I got an like 1.5" on Feb 2, so probably something similar.

[ORH_wxman]

33 minutes ago, CoastalWx said:

The 6z GFS is "probably" the more likely winter scenario vs all snow. You can see at hr 150 we have a s/w that is coming SE and sort of compressing the field a bit to allow the second low underneath SNE. I'm wondering if the easiest route to a colder scenario is to cheer for that, because I feel like a full court press SE is unlikely. 

Yes I think this prob the best way to snow this coming weekend....the PV trends in Canada have been very bad the last 24-36 hours....I suppose they could reverse but I'm growing more skeptical.

[Typhoon Tip]

24 minutes ago, mahk_webstah said:

But doesn’t the correction vector still point colder?

 

There was two reasons one might suspect a colder correction to these mid range products, but the models are carpet surfing reasons to offset them ( lol )

1,  the NAO being negative.  Here's the rub on that... I just noticed that the NAO isn't actually negative at CPC.  I was deferring to a different source before.   So there's discrepancies/argument over the real index depending on what source is used.  The CPC changed their calculation approach last year.  They still use PCA ( Principle Component Analysis - you can look that up.. )  but they now rotate it... "rPCA"    The 'supposed' advantage, is that it lower(raises) the field and exposes a 'truer' value.  Whether that is true in this case or not, it just is what it is ..and right now they are actually positive-neutral-positive.   The other source I've seen is negative.   However, the insistence of these operational runs to run the 13th ( for example ) up the St L. corridor, strikes me as a positive leaning NAO - less colder correction chances.   Or... if all this isn't complicating enough, the NAO ( as we know... ) can be distributed more west or east in the domain. That can f'up the expectations in its own right.  So the bottom line on the "correction vector"  ...it's not as clear.  

2, compression and faster streamline flow tends to offset curved surfaces.  That's just physics.  That's why the wave numbers go down in the heart of winter, because the flow speeds up with seasonal gradient increase.... and this necessarily stretches the L/Ws ...  This principle applies also to the anomalous state of compression that is exaggerated over the continent, which has been demonstrative if not predominating this winter as a predicament.  Anyway ... this tends to keep the trajectories from turning as the deep layer troposphere leans more w-e in the flow type. 

As an aside, the 16th is nuts... Both the EPS and GEFs take a NY Bite low center at 162 or so hours, ...and 6 hours later, it is E of the BM!  That's like 350 naut miles, so this low is moving 60 or 70 mph. 

[dendrite]

12 minutes ago, 40/70 Benchmark said:

You should change your handle to wpc lol

wpc/wu_wx

[40/70 Benchmark]

15 minutes ago, Typhoon Tip said:

 

There was two reasons one might suspect a colder correction to these mid range products, but the models are carpet surfing reasons to offset them ( lol )

1,  the NAO being negative.  Here's the rub on that... I just noticed that the NAO isn't actually negative at CPC.  I was deferring to a different source before.   So there's discrepancies/argument over the real index depending on what source is used.  The CPC changed their calculation approach last year.  They still use PCA ( Principle Component Analysis - you can look that up.. )  but they now rotate it... "rPCA"    The 'supposed' advantage, is that it lower(raises) the field and exposes a 'truer' value.  Whether that is true in this case or not, it just is what it is ..and right now they are actually positive-neutral-positive.   The other source I've seen is negative.   However, the insistence of these operational runs to run the 13th ( for example ) up the St L. corridor, strikes me as a positive leaning NAO - less colder correction chances.   Or... if all this isn't complicating enough, the NAO ( as we know... ) can be distributed more west or east in the domain. That can f'up the expectations in its own right.  So the bottom line on the "correction vector"  ...it's not as clear.  

2, compression and faster streamline flow tends to offset curved surfaces.  That's just physics.  That's why the wave numbers go down in the heart of winter, because the flow speeds up with seasonal gradient increase.... and this necessarily stretches the L/Ws ...  This principle applies also to the anomalous state of compression that is exaggerated over the continent, which has been demonstrative if not predominating this winter as a predicament.  Anyway ... this tends to keep the trajectories from turning as the deep layer troposphere leans more w-e in the flow type. 

As an aside, the 16th is nuts... Both the EPS and GEFs take a NY Bite low center at 162 or so hours, ...and 6 hours later, it is E of the BM!  That's like 350 naut miles, so this low is moving 60 or 70 mph. 

The NAO has is so nuanced...there are like 6 different calculations and the orientation/shape of the heights can have drastically different implications on the pattern. Good luck to anyone trying to soley utilize a numerical index derivative of it in a forecast.

[mahk_webstah]

45 minutes ago, 40/70 Benchmark said:

You should change your handle to wpc lol

I look at them, I read Gray, I find my underground projections are often on target, and obviously I weigh this forum the most heavily

[mahk_webstah]

33 minutes ago, dendrite said:

wpc/wu_wx

Let’s go with win Philly Central

[CoastalWx]

6z Euro looks horrible for the weekend too.

[MJO812]

Mid Atlantic is the new snow capital 

[mreaves]

58 minutes ago, 40/70 Benchmark said:

You should change your handle to wpc lol

mahk_WPC

[WinterWolf]

1 hour ago, RUNNAWAYICEBERG said:

Another failed ssw. Send that and Judah to the moon. 

Wasn’t the SSW supposed to happen this week? Just curious(I’m not following it closely) how has it failed if it hasn’t happened yet?  And any implications are delayed a couple weeks anyway..right.   

[CoastalWx]

Lets get DC with more snow on the season than Tolland.

[Kitz Craver]

13 minutes ago, CoastalWx said:

6z Euro looks horrible for the weekend too.

Horrible. Rain to NNE on DR. Asshole.

[40/70 Benchmark]

1 hour ago, RUNNAWAYICEBERG said:

Another failed ssw. Send that and Judah to the moon. 

PV looks pretty split to me....I think the failure is in assuming that 3 feet of snow should instantaneously apprear in our driveway.

[CoastalWx]

1 minute ago, Kitz Craver said:

Horrible. Rain to NNE on DR. Asshole.

It's why I never get caught up with all these exotic looks 10 days out about sigma anomalies etc. We have a hell of a -AO and that PV is going to do enough that despite that AO look...send a low right up our fannies. 

[CoastalWx]

Instead of buckling up, mother nature is going to strap it on.

[RUNNAWAYICEBERG]

6 minutes ago, WinterWolf said:

Wasn’t the SSW supposed to happen this week? Just curious(I’m not following it closely) how has it failed if it hasn’t happened yet?  And any implications are delayed a couple weeks anyway..right.   

Failure as in, it’s happening…but it’s likely not producing at the surface. 

[CoastalWx]

Bring in the gimp

 

[40/70 Benchmark]

EURO AI is pretty pants-tenty all the way around......Thursday is like 3-4" from I 84 N & W, next weekend another 6-8" outside of 495, and then a big dog next week.

[RUNNAWAYICEBERG]

Pretty h5 colors.

[Typhoon Tip]

2 minutes ago, 40/70 Benchmark said:

PV looks pretty split to me....I think the failure is in assuming that 3 feet of snow should instantaneously apprear in our driveway.

There's also no propagating ( down welling ...) SSW spanning the last 20+ days

- this is an ordeal above that aroused via other wholesale mechanics.  

 

[40/70 Benchmark]

4 minutes ago, RUNNAWAYICEBERG said:

Failure as in, it’s happening…but it’s likely not producing at the surface. 

They seldom produce immediately....like folks have been saying, wait until the tropics begin to align with what is going on at the pole.