February Mid/Long Range Discussion

[psuhoffman]

The feb 2 deal taking a step back is disappointing.  And because of the lower QPF with that the overall numbers, as ji posted, took a step down.  But there are multiple threats still on the table.  And Feb 2 isnt completely dead yet. 

The GEFS did take a step back overall but still has a healthy look for snowfall overall.  The threats, as Bob accurately pointed out are spread out and each one looks to be a minor event, 1-3" type deal, but there are several and each does hold some potential to be moderate if things break right.  But I posted the other day that the look on the pattern the next 10-14 days is one of small events not big.  Towards the end the pattern looks more favorable for something bigger and that has not changed. 

The EPS actually just had the weeniest snowfall run of the winter so far.  Snowfall mean is around 5-6" for most of the area.  Again its spread out over several threats but overall only about 15% of EPS members manage not to get DC 2" of snow in the next 15 days.  Just like with the GEFS I like the look towards the end much more for a significant event.  

Overall the last 24 hours wasnt the best and took a small step back but people are way over reacting.  Things still look fairly promising for snow chances in the next few weeks.   I am not blind to the fact that things have failed as they near short range this year, so skepticism is ok and fine.  And its ok to point that out.  But if you have totally given up to the point you don't even want us speculating on chances then why bother even reading this thread.  

That is my honest assessment of where we are.  I still think it is unlikely we dont get some snow in the next 2 weeks.  I think that snow is probably going to be on the minor event side but I doubt a shutout.  After that I think the chances of a moderate or better event go up with the look were seeing towards mid february.  

[Bob Chill]

GFS is slowly trending back towards digging h5 in the plains after being really flat a few days ago. If you want to know what to track for increased precip along the front, watch the dig over the great plains. 12z looks better than the last 3 runs. 

[frd]

36 minutes ago, Isotherm said:

 

Yeah, the +NAO was a mainstay of my winter forecast again this year. The AO is averaging close to neutral for the winter thus far, and the NAO positive. The Atlantic is a factor (as is the Pacific), and exogenous variables like solar. The coupled indicator I've been using has shown excellent success (retrospectively 87% since 1950). I'd rather not discuss details but what I will say is that the end of +NAO cycle, in the means, is rapidly approaching.

Isotherm your NAO call for this winter, o far has been great. Without stating more than is needed is the cause for the NAO change coming up more so ocean driven or solar, or other factors.  Thanks as always. By the way while you are here do you think the Atlantic wave activity I hear about coupled with the Pac will produce anything meaningful for March as there is a lag.  Jason Furtado was talking about it recently. Not common for the Atlantic wave pulses to be involved but it is forecasted to.  

 

[Bob Chill]

Significantly more precip this run with the gfs. Mids are great but surface causes most of it to fall as rain or non-accum snow. Unlike no precip, we can work with temps. Walking the line

[stormy]

4 hours ago, NutleyBlizzard said:

That's a typical La Nina pattern. Pattern is just to progressive to produce a large event. With the lack of Atlantic blocking, every time a shortwave tries to dig there's a kicker on its heels to shunt everything out. Very frustrating. That's what makes the winters of 1995-96 and 2010-11 so special. 

I agree with much of what you say, but the mystery is this.  1995 -96 was a La Nina winter averaging -.9C. The winter of 2010 - 11 was also a La Nina winter averaging -1.1C.

[BTRWx's Thanks Giving]

5 minutes ago, stormy said:

I agree with much of what you say, but the mystery is this.  1995 -96 was a La Nina winter averaging -.9C. The winter of 2010 - 11 was also a La Nina winter averaging -1.1C.

Fwiw, the western Atlantic had negative sst anomalies for January both those years.

[Bob Chill]

8 minutes ago, stormy said:

I agree with much of what you say, but the mystery is this.  1995 -96 was a La Nina winter averaging -.9C. The winter of 2010 - 11 was also a La Nina winter averaging -1.1C.

There's no mystery. Both those years had nao blocking the balance of winter. 2010-11 had a very strong -nao that flippped at the end of January. That was the last time we've had a persistent -nao. 

[pasnownut]

57 minutes ago, Isotherm said:

 

Yeah, the +NAO was a mainstay of my winter forecast again this year. The AO is averaging close to neutral for the winter thus far, and the NAO positive. The Atlantic is a factor (as is the Pacific), and exogenous variables like solar. The coupled indicator I've been using has shown excellent success (retrospectively 87% since 1950). I'd rather not discuss details but what I will say is that the end of +NAO cycle, in the means, is rapidly approaching.

Boy I sure hope that last sentence is correct ISO.  Great seeing you in here btw.

 

[Interstate]

Another VA Beach special showing up on the GFS.  Maybe they should buy all of our snowplows.

[stormy]

2 minutes ago, Bob Chill said:

There's no mystery. Both those years had nao blocking the balance of winter. 2010-11 had a very strong -nao that flippped at the end of January. That was the last time we've had a persistent -nao. 

Thanks Bob! That explains a lot.

[pasnownut]

23 minutes ago, Bob Chill said:

Significantly more precip this run with the gfs. Mids are great but surface causes most of it to fall as rain or non-accum snow. Unlike no precip, we can work with temps. Walking the line

yeah IMO 12z was a nice improvement for next 2 in line.  Nice uptick for sure.  

[stormy]

5 minutes ago, BTRWx's Thanks Giving said:

Fwiw, the western Atlantic had negative sst anomalies for January both those years.

The Atlantic sst anomalies are certainly toasty off the MA this year.

[Bob Chill]

3 minutes ago, stormy said:

Thanks Bob! That explains a lot.

I circled what to look for on guidance when assessing a pattern that can produce bigger snow storms and extended cold. The block near greenland suppresses storm track and locks cold air into the east. We haven't had a good -NAO since Jan 2011. It's coming back eventually. The pattern we're heading towards more closely resembles Feb of 2014&15 with fast progressive flow. There will be cold and storm chances but the windows will open and close quickly and cold will move in and out quickly too. With no block near greenland, everything can just zip across the Conus and out into the atlantic. We can still get snow but without something to slow the flow down or keep storms from cutting we have a much higher risk of rain and most (if not all) precip events will be smaller. .25-.50" is a solid event in progressive flow. .5-1" qpf is a big event in progressive flow.

[BTRWx's Thanks Giving]

11 minutes ago, Bob Chill said:

There's no mystery. Both those years had nao blocking the balance of winter. 2010-11 had a very strong -nao that flippped at the end of January. That was the last time we've had a persistent -nao. 

Whoever learns what drives the NAO at long range deserves a Nobel prize.  The future!

[Bob Chill]

10 minutes ago, pasnownut said:

yeah IMO 12z was a nice improvement for next 2 in line.  Nice uptick for sure.  

GFS/CMC/ICON and even last night's Euro all showed tightly spaced shortwaves running through the flow with cold lurking. There will be more chances. They won't be well modeled outside of 3-4 days tops but there will be things to watch. Even if something looks like crap d5+, the chance of the solution remaining static at that lead is near zero. I said when we were heading into this pattern that it's high risk/high reward and won't be for the faint of heart. Nothing can be completely written off or hugged until inside of 3 days. We just need to be close and all the ops are close. 

[pasnownut]

42 minutes ago, Bob Chill said:

GFS is slowly trending back towards digging h5 in the plains after being really flat a few days ago. If you want to know what to track for increased precip along the front, watch the dig over the great plains. 12z looks better than the last 3 runs. 

CMC is also now headed SE at 500 for Friday.  Take a look.  Nice step 

[Interstate]

Would be nice to have something pull the SL out of the GoM at 222

[Bob Chill]

3 minutes ago, BTRWx's Thanks Giving said:

Whoever learns what drives the NAO at long range deserves a Nobel prize.  The future!

There isn't always a reason for things. Long lead will be more of an art than a science for as long as I'm alive unless there is a breakthrough (which I doubt). Global weather is exceptionally complicated. Sometimes just accepting that weather is just weather and not worrying about the whys is better than trying to figure it out. Cohen "thought" he had a breakthrough with the SAI. That has proven to be as reliable as a 1982 Chrysler K car. 

[pasnownut]

cmc at 96.  HMMMM

[Interstate]

Bob... would it be correct to say that we are close to some good at 234 if the energy could phase?

[psuhoffman]

2 minutes ago, Bob Chill said:

GFS/CMC/ICON and even last night's Euro all showed tightly spaced shortwaves running through the flow with cold lurking. There will be more chances. They won't be well modeled outside of 3-4 days tops but there will be things to watch. Even if something looks like crap d5+, the chance of the solution remaining static at that lead is near zero. I said when we were heading into this pattern that it's high risk/high reward and won't be for the faint of heart. Nothing can be complete written off or hugged until inside of 3 days. We just need to be close and all the ops are close. 

I am still general positive on our chances to get one of these to work out.  However, seeing both the GFS and GGEM runs with a train of northern stream systems going just north and southern stream systems staying just south gives me some pause.  Everytime we have a nina people say "we just keep getting unlucky" when storms go just north and just south of us, when in reality thats what a nina does much of the time.  There is a reason the snowfall anomaly map for a nina shows the greatest negative departures right over us with more snow WRT normal both north and south of us.  

It seems to me that the progressive northern stream and weaker southern stream we typically get in a nina, and have this year, would naturally lead to that.  The northern stream vorts are racing along with kickers constantly preventing buckling to dig under us without those exception years with blocking.  The STJ is weak and so with a fast NS blasting by to the north with little chance anything can phase and with the stj weak its unlikely it can bully its way up to us without phasing.  So "stuck in between" is our default setting unfortunately in a nina without NAO blocking.  

Now that said many Nina's we do finally luck our way into something.  1995 the early Feb storm.  1999 early March.  2000 we had one epic week.  2001 we at least had that wave Jan 20.  2006 we lucked into the Feb MECS.  So MOST nina's while the majority go north or south of us at least one finally from sheer luck finds its way over us.  The pattern is active enough that at least our chances of that luck happening are higher because there will be more opportunity, but the pattern does favor north and south of us.  Thats not bad luck, its nina.  

[Bob Chill]

1 minute ago, Interstate said:

Bob... would it be correct to say that we are close to some good at 234 if the energy could phase?

Yea, it's digital close. CMC is actually a couple hits with weaker waves. Stability will be virtually non-existent though. If anything looks good inside of 4 days then it can be considered real. Until then it's just episodes of your favorite (or least favorite) tv show and not the nightly news. 

[stormy]

15 minutes ago, Bob Chill said:

I circled what to look for on guidance when assessing a pattern that can produce bigger snow storms and extended cold. The block near greenland suppresses storm track and locks cold air into the east. We haven't had a good -NAO since Jan 2011. It's coming back eventually. The pattern we're heading towards more closely resembles Feb of 2014&15 with fast progressive flow. There will be cold and storm chances but the windows will open and close quickly and cold will move in and out quickly too. With no block near greenland, everything can just zip across the Conus and out into the atlantic. We can still get snow but without something to slow the flow down or keep storms from cutting we have a much higher risk of rain and most (if not all) precip events will be smaller. .25-.50" is a solid event in progressive flow. .5-1" qpf is a big event in progressive flow.

Thanks again Bob!  And of course the Greenland block encourages the good ole 50/50 low.

[frd]

30 minutes ago, BTRWx's Thanks Giving said:

Whoever learns what drives the NAO at long range deserves a Nobel prize.  The future!

 Well.............................An accurate NAO forecast at long leads is to weather hobbyists and Mets as the location and existence of the Holy Grail is to Indiana Jones 

 

[frd]

24 minutes ago, Bob Chill said:

I circled what to look for on guidance when assessing a pattern that can produce bigger snow storms and extended cold. The block near greenland suppresses storm track and locks cold air into the east. We haven't had a good -NAO since Jan 2011. It's coming back eventually. The pattern we're heading towards more closely resembles Feb of 2014&15 with fast progressive flow. There will be cold and storm chances but the windows will open and close quickly and cold will move in and out quickly too. With no block near greenland, everything can just zip across the Conus and out into the atlantic. We can still get snow but without something to slow the flow down or keep storms from cutting we have a much higher risk of rain and most (if not all) precip events will be smaller. .25-.50" is a solid event in progressive flow. .5-1" qpf is a big event in progressive flow.

Bob, what you have referecned here is very similiar to the long range looks on the Nina + MJO plots DT has on his recent snow podcast. 

Seems that you have similiar looks in both El Nino and La Nina years,  but the 500 mb strenght and placements are slightly differant , again based on Nina or Nino.   Less pronouced in a La Nina , more so in a Nino. 

 

 

[BTRWx's Thanks Giving]

4 minutes ago, frd said:

Bob, what you have referecned here is very similiar to the long range looks on the Nina + MJO plots DT has on his recent snow podcast. 

Seems that you have similiar looks in both El Nino and La Nina years,  but the 500 mb strenght and placements are slightly differant , again based on Nina or Nino.   Less pronouced in a La Nina , more so in a Nino. 

 

 

It's possible, but those two years alone aren't enough to make that conclusion.

[frd]

11 minutes ago, BTRWx's Thanks Giving said:

It's possible, but those two years alone aren't enough to make that conclusion.

I am really looking forward to see the progression towards the mid and end of part of Feb. Always something new to learn.  

[Bob Chill]

Not the worst spread embedded in here for a week down the line. A number of gefs solutions have a pretty good track with good hp placement to the N. This panel doesn't capture the full spread due to timing but it's close enough and worth watching over time. It's a timing type of deal of course because the hp to the north is certainly not locked in place but this is reminiscent of the types of events in feb 14/15.

[baltimoreguy]

1 hour ago, frd said:

 Well.............................An accurate NAO forecast at long leads is to weather hobbyists and Mets as the location and existence of the Holy Grail is to Indiana Jones 

 

Something to leave behind even as a European model clutches for it and instead plummets into a bottomless pit?

[Bob Chill]

Euro drops .3-.4 again across the region Friday but temps don't cooperate until the end. Mids are good. Surface is not. 35-39 degrees at onset. All we can do is hope it trends colder. Most guidance is coming in around .2-.4 for the wave/front now so that part is better than what the gfs showed yesterday. Just need some luck in the temp department.