December Medium/Long Range Discussion

[DownpourDave]

Regardless how this ends up, love the look of a strong high pressure overtop to prevent the storm from cutting. 

 

Edit: Unfortunately, the high pressure system moves out of the way allowing the low pressure system over Texas to cut. 

 

 

 

[psuhoffman]

7 minutes ago, SnowLover22 said:

Regardless how this ends up, love the look of a strong high pressure overtop to prevent the storm from cutting. 

 

Edit: Unfortunately, the high pressure system moves out of the way allowing the low pressure system over Texas to cut. 

 

 

 

Trough is way too amplified too far west. Pumps ridging ahead. No confluence. Cutter. But a whole lot of higher heights up top by day 10. I know patience is difficult but after the AO/NAO bottoms out and starts to relax is our favored time. 

[psuhoffman]

One last observation. The runs that show snow around New Years do so by splitting the energy out west. There are multiple SWs crashing in next week. Runs that keep them separated and bring them out in pieces are further south. If they consolidate into one amplified trough out west the storm cuts. 

[psuhoffman]

Day 10 

That’s a lot of red in the right places 

[yoda]

2 minutes ago, psuhoffman said:

Day 10 

That’s a lot of red in the right places 

I was going to say Day 10 (of course it does since its Day 10 lol)  looked enticing at h5... probably get a storm chance in the few days after

[Vice-Regent]

2 hours ago, psuhoffman said:

Finally starting to see the temp anomalies we need showing up.  

 

However with a torched source region for arctic airmasses and an increasing sun angle is a recipe for disaster. I am not surprised anyone can look at these graphics with a semblance of sanity and see the writing on the wall. The corona extinction of aerosols is what got us but we were already close to the end.

 

[CAPE]

3 hours ago, psuhoffman said:

@Ji Just sayin maybe we should let this play out. The blocking is just establishing itself next week. With each wave break it retrogrades more into a canonical blocking regime.  Both the TPV and SPV look to get obliterated soon.  We typically score after the blocking peaks not before. 

Yeah its going to take some patience, Both the EPS and GEFS build the +heights  more NW towards the Davis strait by the first week of Jan. Until then its going to be a struggle to get something to track underneath with a lot of energy dropping down so far west, and the NA ridge in the near term displaced too far east.

[CAPE]

Hopefully this doesn't become a can kicking exercise in the LR. This is where we want the block, and we hope for some Pacific cooperation. This is a good look right here.

EPS has an impressive west based -NAO as well, but maybe a bit less favorable look out west.

 

[Ji]

6 hours ago, psuhoffman said:

Not hating the mean precip distribution  during that same period either 

there is a big hole over DC 

[PivotPoint]

5 hours ago, psuhoffman said:

Day 10 

That’s a lot of red in the right places 

Unfortunately, the blue is all types of wrong out west lol. It’s always 10 days away @psuhoffman lol. Crazy block though 

2 hours ago, CAPE said:

Hopefully this doesn't become a can kicking exercise in the LR. This is where we want the block, and we hope for some Pacific cooperation. This is a good look right here.

EPS has an impressive west based -NAO as well, but maybe a bit less favorable look out west.

 

Again, one frame at 384 hours. And flow looks pretty flat coming off the PAC. I’m beginning to worry that we won’t score with a bad PAC and troughing south of AK. Seems like that a recipe for warm wet, cold dry sequence over and over again. Can’t not expect it though. That’s kinda La Niña for you

[PivotPoint]

5 minutes ago, Ji said:

there is a big hole over DC 

It’s more over you. Leesburg SH.

[aldie 22]

8 minutes ago, Ji said:

there is a big hole over DC 

No that is over Leesburg

[aldie 22]

4 minutes ago, PivotPoint said:

Unfortunately, the blue is all types of wrong out west lol. It’s always 10 days away @psuhoffman lol. Crazy block though 

Again, one frame at 384 hours. And flow looks pretty flat coming off the PAC. I’m beginning to worry that we won’t score with a bad PAC and troughing south of AK. Seems like that a recipe for warm wet, cold dry sequence over and over again. Can’t not expect it though. That’s kinda La Niña for you

Let me guess, you always approach model and map reading with a "what could go wrong" eye?

[frd]

5 hours ago, psuhoffman said:

One last observation. The runs that show snow around New Years do so by splitting the energy out west. There are multiple SWs crashing in next week. Runs that keep them separated and bring them out in pieces are further south. If they consolidate into one amplified trough out west the storm cuts. 

 

Seems as though there will be multiple +EAMT events upcoming.  Hopefully, this provides a few +PNA intervals, coinciding with a storm threat for us in January. 

 

 

 

[frd]

 

Member count continues to increase. 

 

 

[frd]

 

Looking forward to the next update, but this is rather impressive and starts in only a few days,  

 

 

[PivotPoint]

33 minutes ago, leesburg 04 said:

Let me guess, you always approach model and map reading with a "what could go wrong" eye?

Not at all. If you go back and read my posts starting 3+ weeks back I talked about how I thought that LR looked good for cyclical blocking regime and an Atlantic that is not fighting us. Haven’t had that combo in awhile.

I read maps at an amateur level anyways. So it probably doesn’t matter lol. But no, I just see what I see. And when it looks good I say so. When it doesn’t, I say so. It just happens that it looks not good more than it looks good. That’s our climo

[CAPE]

12 minutes ago, PivotPoint said:

Not at all. If you go back and read my posts starting 3+ weeks back I talked about how I thought that LR looked good for cyclical blocking regime and an Atlantic that is not fighting us. Haven’t had that combo in awhile.

I read maps at an amateur level anyways. So it probably doesn’t matter lol. But no, I just see what I see. And when it looks good I say so. When it doesn’t, I say so. It just happens that it looks not good more than it looks good. That’s our climo

Despite all the imperfectness, somehow things align in a way to produce snow a few times almost every winter.

[poolz1]

7 hours ago, psuhoffman said:

 

To me, the most surprising aspect of that mean is the lower heights off the west coast and extending into AK.  Would not have expected that to be the case.  Just south enough to give a little PNA love....doesnt have to be some monster PNA ridge out west.

[MillvilleWx]

3 minutes ago, poolz1 said:

To me, the most surprising aspect of that mean is the lower heights off the west coast and extending into AK.  Would not have expected that to be the case.  Just south enough to give a little PNA love....doesnt have to be some monster PNA ridge out west.

The ridge alignment is literally perfection with that setup too. You want those + height anomalies over ID/W MT for a reflection of SLP track along and off the eastern seaboard. The premise of 100-200 miles in exact placement of succinct ridge/trough patterns is a marvel to think about on a hemispheric scale. The big ones need that star alignment, and the fact it happens as often as it does is pretty outstanding. I love weather  

[dallen7908]

7 hours ago, psuhoffman said:

@Ji Just sayin maybe we should let this play out. The blocking is just establishing itself next week. With each wave break it retrogrades more into a canonical blocking regime.  Both the TPV and SPV look to get obliterated soon.  We typically score after the blocking peaks not before. 

I wonder when this will be .. The AO and NAO look stable and negative for the last few days of 2020 and the first week of 2021. 

The DC-proper snow means from the GEFS and EPS for the next 10-15 days are less than 1" (below the 2" amount that is typical this time of year)

The good news is the large-scale pattern is not close-the-window-shades bad.  Its been a decade since we've had anything in the mid-range to track in late December - still a chance this year. 

[psuhoffman]

2 hours ago, PivotPoint said:

Unfortunately, the blue is all types of wrong out west lol. It’s always 10 days away @psuhoffman lol. Crazy block though 

Again, one frame at 384 hours. And flow looks pretty flat coming off the PAC. I’m beginning to worry that we won’t score with a bad PAC and troughing south of AK. Seems like that a recipe for warm wet, cold dry sequence over and over again. Can’t not expect it though. That’s kinda La Niña for you

Is it...the blues out west look pretty close to this...

Remember blocking changes what works out west.   Without blocking that wouldn’t work.  With blocking you want that trough off the west coast to kick everything along and promote enough ridging over the CONUS to prevent suppression. If we had what we think of as a ideal pac with great blocking everything would get squashed. That’s a cold dry look.  On the plot you posted I don’t see a disaster. The WPO vortex backed off enough to allow some epo ridging. The system south of AK is far enough south not to flood pac puke across.  It’s part of the flow not detached. I’d like a little more pna but it’s not bad.  If we have blocking.

1 hour ago, poolz1 said:

To me, the most surprising aspect of that mean is the lower heights off the west coast and extending into AK.  Would not have expected that to be the case.  Just south enough to give a little PNA love....doesnt have to be some monster PNA ridge out west.

Look at my response above. I think some are looking for the “ideal” pac but what is ideal changes based on other factors. It’s a balance. What’s on one side changes what we want on the other. A full latitude EPO/PNA ridge at the same time as a -AO/NAO is really rare. First of all you almost need the tpv to either drop into the US or completely vacate our side to get that. And when we have gotten that mid winter it’s tended to be a cold dry look. Think Jan 1977. 

52 minutes ago, dallen7908 said:

I wonder when this will be .. The AO and NAO look stable and negative for the last few days of 2020 and the first week of 2021. 

The DC-proper snow means from the GEFS and EPS for the next 10-15 days are less than 1" (below the 2" amount that is typical this time of year)

The good news is the large-scale pattern is not close-the-window-shades bad.  Its been a decade since we've had anything in the mid-range to track in late December - still a chance this year. 

Imo the snow mean hasn’t responded yet because after the New Years storm it’s dry. And that’s to be expected with that blocking look. The New Years period is the HA storm on the front end as the blocking goes up. The wave break from those 2 systems help get the block into our canonical location. Once there though waves will likely slow down over the CONUS...blocking. We would then need the blocking to start to relax some. Or...the Feb 2010 option when a really strong stj wave attacked the blocking aided by a trough off the west to promote enough ridging (and the wave was strong enough not to shear out) to get that moisture to attack the block.  But waves will likely be less frequent after the blocking establishment 

[psuhoffman]

4 hours ago, CAPE said:

Hopefully this doesn't become a can kicking exercise in the LR. This is where we want the block, and we hope for some Pacific cooperation. This is a good look right here.

EPS has an impressive west based -NAO as well, but maybe a bit less favorable look out west.

 

EPS look out west is more problematic.  Not a total deal breaker...we have had some good snowstorms in that look but its not as common as if that trough stays centered off the west coast a bit more allowing just a little bit of PNA ridge into the southwest.  Perfect blocking can erase a lot of issues in other areas though.  I wonder if we saw this....would we pick apart the less then ideal pacific?

[psuhoffman]

Keep in mind also...when you look at the ensemble means at day 10-15 because of timing differences on waves details get washed out.  The blue in the west is not a big huge trough...its from pacific waves crashing in every couple days.  We need those waves...hopefully one of them ends up our snowstorm.   There would be short periods with some PNA ridging in between imo...but its getting washed out by the lower heights of the waves crashing and the timing differences between members.  

[howrdcounty snow]

1 minute ago, psuhoffman said:

Keep in mind also...when you look at the ensemble means at day 10-15 because of timing differences on waves details get washed out.  The blue in the west is not a big huge trough...its from pacific waves crashing in every couple days.  We need those waves...hopefully one of them ends up our snowstorm.   There would be short periods with some PNA ridging in between imo...but its getting washed out by the lower heights of the waves crashing and the timing differences between members.  

sir would you define the waves crashing into west coast as the southern jet??

[CAPE]

10 minutes ago, psuhoffman said:

EPS look out west is more problematic.  Not a total deal breaker...we have had some good snowstorms in that look but its not as common as if that trough stays centered off the west coast a bit more allowing just a little bit of PNA ridge into the southwest.  Perfect blocking can erase a lot of issues in other areas though.  I wonder if we saw this....would we pick apart the less then ideal pacific?

Nina vs Nino background state is one difference. Pac is inherently more hostile to our snow chances during a typical Nina, although this may be less of a factor now and moving forward.

[psuhoffman]

5 minutes ago, howrdcounty snow said:

sir would you define the waves crashing into west coast as the southern jet??

I saw one pure STJ wave. Others were polar jet in origin.  But that’s ok when they eject into the plains they can pick up stj moisture. 

[psuhoffman]

4 minutes ago, CAPE said:

Nina vs Nino background state is one difference. Pac is inherently more hostile to our snow chances during a typical Nina, although this may be less of a factor now and moving forward.

True but I haven’t seen much of a typical Nina response yet. 

[Eskimo Joe]

 

[howrdcounty snow]

1 minute ago, Eskimo Joe said:

 

isn't that the cold air were hoping for as critical ingredient for snow, among others?