January Mid-Long Range Disco

[mitchnick]

2 minutes ago, psuhoffman said:

Gfs teasing at 384 hours. All feels right in the world. 

Teasing? Nah....getting ready to shove that Great Lakes low down our throats just when we think we're going to score. I like the way it tries to hide it from us. Lol 

[WxUSAF]

47 minutes ago, psuhoffman said:

.  It's called bad luck. 

You misspelled La Niña.

[poolz1]

This arctic front will at least be interesting weather....The euro really crashes temps overnight Fri... HGR for example, 58* at 7pm, 23* at 7am with gusts 30+.  Precip looks to be close to an inch before the flash freeze.  Salt will be washed off the road and especially bridges and overpasses. Fortunately, it's a weekend but need to keep close tabs if you are heading out early sat morn. 

[Quasievil]

If you feel like torturing yourself by taking the 18Z GFS out to 384, you'll find that the snow hole over Maryland is no joke. Oh, wait, except for the new Southern New England, aka, the Eastern Shore.

[Bob Chill]

Thank you very much @Isotherm. Most of what you said makes complete sense. Here's my translation:

-The trop -AO is probably transient and not part of a wholesale regime change

-Any meaningful changes in the strat are either going to happen in Feb or not at all

-The mid-atlantic will need to keep hoping for luck embedded in hostile flow for snow chances until further notice

-The best chance for blocking and/or a decent pattern for snow won't come until the second week of Feb and beyond

 

The latest weeklies run agrees with your thoughts as well. The npac looks out of sync and hostile until after the first week of Feb. What I'm hoping for is that the AO will be generally negative for at least a couple weeks. If we're going to have a dominant northern stream AND persistent lower heights in the NE Pac then we need all the help we can get to push something under us. The -AO can do that if the mid latitude wavelengths time something right. I've seen many small or moderate storms hit our area in an otherwise hostile pattern. Especially from Mid Jan - Mid Feb. Once we get to late Feb then climo temps start to fight back pretty hard. 

 

 

[Bob Chill]

The ICON model is on its own but the way it snows on us is worth keeping an eye out for as we get closer. The shortwave is slow moving and it's likely going to jump the coast north of us but no way to say anything definitive other than that's the way it usually works. However, the slow speed can set up an inverted trough type of precip event as low pressure stretches out and elongates between the initial low to the west and the eventual low off the coast. You don't have to rely on organized low pressure. Sometimes being in between can work. Often these types of events happen way to fast and it ends up being a band of flurries or light snow at best. If the process of transferring and deepening off the coast is more drawn out (like it looks like right now) then someone will probably get under some half decent precip before the coastal starts winding up. I'm still not a liking what I see but the slower speed can change the outcome from typical to atypical. 

[psuhoffman]

There is more support on the gefs for something forced under us by the blocking in the day 10-15 period then I expected. 

[BristowWx]

50 minutes ago, Bob Chill said:

Thank you very much @Isotherm. Most of what you said makes complete sense. Here's my translation:

-The trop -AO is probably transient and not part of a wholesale regime change

-Any meaningful changes in the strat are either going to happen in Feb or not at all

-The mid-atlantic will need to keep hoping for luck embedded in hostile flow for snow chances until further notice

-The best chance for blocking and/or a decent pattern for snow won't come until the second week of Feb and beyond

 

The latest weeklies run agrees with your thoughts as well. The npac looks out of sync and hostile until after the first week of Feb. What I'm hoping for is that the AO will be generally negative for at least a couple weeks. If we're going to have a dominant northern stream AND persistent lower heights in the NE Pac then we need all the help we can get to push something under us. The -AO can do that if the mid latitude wavelengths time something right. I've seen many small or moderate storms hit our area in an otherwise hostile pattern. Especially from Mid Jan - Mid Feb. Once we get to late Feb then climo temps start to fight back pretty hard. 

 

 

Of all the posts you’ve made that one was the most sobering.  2nd week of Feb would literally burn through all of our prime climo. That is startling and didn’t expect us to be in this position.  

[Bob Chill]

1 minute ago, psuhoffman said:

There is more support on the gefs for something forced under us by the blocking in the day 10-15 period then I expected. 

The big block showing up over the pole can help create opportunity. The h5 ens mean in the east is deceiving. It's not going to be 5 or 10 days of constant ridging. Shortwaves and fronts will be embedded in the mid latitudes. On average heights will be AN due to the downstream response of mutiple troughs hitting the pac NW but the pattern is far from a persistant ridge like we see sometimes in the winter. 

I've been looking at the ens memeber temp panels and things go haywire out in time. Lots of cold and warm solutions for any given day. Some are very cold and others are furnaces so the ens mean averages look above normal but nothing crazy. In reality is either going to be a good bit below normal or down right balmy. We just need the right spacing so a shortwave can take advantage when the cold is in place. 

One thing for sure, there is going to be a heck of a lot more precip events across the conus over the next 2-3 weeks compared to the last 2-3 weeks. I wouldn't call the advertised pattern a shutout pattern. Odds will favor wet over white in general but if something does hit us down the line it won't surprise me much at all. 

[Isotherm]

3 hours ago, psuhoffman said:

I get the sense from your posts up in the NYC threads that you probably think the places down this way that are still waiting for snow are in pretty big trouble this year. Piecing together your posts you seem pretty down on any snow chances for the next month or so. And down here climo starts becoming a problem after that. Would it be fair to say you think it's very likely we finish well below climo snow again?  Not saying I disagree just trying to let you elaborate since your thoughts for NYC don't decessarily match here. Love your analysis btw. Thanks for your thoughts. 

 

Psu, thanks. Unfortunately, your interpretation is generally correct. I went 9-16" and 12-19" for DCA and BWI respectively this winter, sub normal; not shut-outs though. I think most of that snowfall will occur after February 1st. As Bob mentioned, it's possible a light event occurs within the hostile Pacific flow, but it would probably be of the 1-3/2-4 variety. Peak climatology is coming up, so light events can occur in poor regimes. I'm not much more enthused for my area into NYC/coastal SNE either. Boston will likely do better with spasmodic poleward Aleutian ridging suppressing heights a bit to the north, but not a great pattern for them either through week 3 at least. Hopefully I'm wrong and a better pattern evolves more quickly.

 

45 minutes ago, Bob Chill said:

Thank you very much @Isotherm. Most of what you said makes complete sense. Here's my translation:

-The trop -AO is probably transient and not part of a wholesale regime change

-Any meaningful changes in the strat are either going to happen in Feb or not at all

-The mid-atlantic will need to keep hoping for luck embedded in hostile flow for snow chances until further notice

-The best chance for blocking and/or a decent pattern for snow won't come until the second week of Feb and beyond

 

The latest weeklies run agrees with your thoughts as well. The npac looks out of sync and hostile until after the first week of Feb. What I'm hoping for is that the AO will be generally negative for at least a couple weeks. If we're going to have a dominant northern stream AND persistent lower heights in the NE Pac then we need all the help we can get to push something under us. The -AO can do that if the mid latitude wavelengths time something right. I've seen many small or moderate storms hit our area in an otherwise hostile pattern. Especially from Mid Jan - Mid Feb. Once we get to late Feb then climo temps start to fight back pretty hard. 

 

 

 

 

Thanks Bob. You're correct on that interpretation and I agree on all counts. I saw tonight's weeklies and generally concur with its overall progression. As noted above, I think Feb 6-7+ (+/- a few days) is when the reshuffle with more conducive tropical forcing in conjunction w/ weak vortex anomalies truly manifest more strongly. This isn't too atypical, but I think DCA/BWI probably get 80%+ of their winter snow in February.

[Isotherm]

Keep in mind the GEFS has had a history of overestimating high latitude blocking in the LR. I would weight the EPS more strongly than GEFS.

[Bob Chill]

5 minutes ago, BristowWx said:

Of all the posts you’ve made that one was the most sobering.  2nd week of Feb would literally burn through all of our prime climo. That is startling and didn’t expect us to be in this position.  

It wasn't doom and gloom. My last post goes into more detail as to how I see things happening. The conus is entering a very active period with numerous shortwaves hitting the west coast. We just exited a bone dry couple of weeks. Yea, it was cold as hell but overall the pattern sucked for synoptic storms across almost the entire country. That is changing. We're probaby in the most optimal period to have something work out without needing a -10 air mass. 

[Bob Chill]

5 minutes ago, Isotherm said:

Keep in mind the GEFS has had a history of overestimating high latitude blocking in the LR. I would weight the EPS more strongly than GEFS.

It has for sure but that trend actually reversed right around the beginning of the year. The gefs busted high with the AO in the 10 and 14 day forecast period for the first time. The upcoming -ao period popped  up fairly abruptly and long range guidance didn't really show it coming. I would not be surprised at all if the -AO flexes for several weeks or even longer. Won't know the answer for another 10 days or so. I got fooled in late November once already. We'll see how it goes this time. I originally went around 75% of climo snow in our contest thread but changed my numbers to above climo when the -ao fooled me.  I'm still kicking myself for not sticking with my gut...lol

The weeklies favored more of a -ao than a + one. Smoothed means out in time can be hard to decipher. I'm pretty interested in the next couple weeks. 

[Isotherm]

12 minutes ago, Bob Chill said:

It has for sure but that trend actually reversed right around the beginning of the year. The gefs busted high with the AO in the 10 and 14 day forecast period for the first time. The upcoming -ao period popped  up fairly abruptly and long range guidance didn't really show it coming. I would not be surprised at all if the -AO flexes for several weeks or even longer. Won't know the answer for another 10 days or so. I got fooled in late November once already. We'll see how it goes this time. I originally went around 75% of climo snow in our contest thread but changed my numbers to above climo when the -ao fooled me.  I'm still kicking myself for not sticking with my gut...lol

The weeklies favored more of a -ao than a + one. Smoothed means out in time can be hard to decipher. I'm pretty interested in the next couple weeks. 

 

Yeah, there will be a -AO in the means, but that's generally an ineffectual signal when coupled with a poor Pacific and less than favorable NAO. A -AO contemporanous with low heights on the West Coast can work if the -NAO is stronger, which I'm not seeing for awhile. Like you said, it'll temper the torch and maybe offer some light events. 

[gymengineer]

Matt posted about this maybe a week or more ago and I think it’s worth emphasizing — prime climo for our snow season is the latter part of January through mid/late February. The lamenting about February sun angle always happens. And I get it; snow melts sooner in February than January all things else equal. But there’s a reason that period continues to average higher decade after decade. 

In other words, if February is not downright hostile in general pattern, I will still perceive it as a month of likely getting accumulating snow.

And as for being in the midst of a sucky season— it would still give me more hope of eventually getting a decent snow if others northeast of us continue to score. That remains to be seen for this season, but it’s why I’m not mad at a northeast hit in the next week. Storm track progression down the coast happens in many seasons that are good Northeast seasons (like 77/78, 92/93, 04/05, 10/11,14/15) where we eventually get one or more decent event. Sometimes we have to wait until March. Many are not blockbusters or even above average here, but they weren’t in the bottom scraper seasons either. If no one is scoring anywhere along the corridor, then the currently sucky winter more likely heads into absolute clunker territory. 72/73, 94/95 which actually wasn’t garbage for here, 97/98, 01/02, 11/12, etc.— those were debacles up and down the Megalopolis. 

[psuhoffman]

Bob noticed how the trough keeps slowing down. It's really slowing on the gfs. The lead vort isn't digging as much. But i wonder if it's going to leave room for something else to happen with the trough behind that clipper. Some ensemble members did that. The craziest one being the blizzard EPS member I posted. 

[psuhoffman]

Hmm so it's a long shot and it don't look like much at the surface, just a weak wave over the southeast, but get the vort at the base of the trough a bit more amplified and get it to cut off and suddenly we have that EPS run I posted. That one was crazy but there were several EPS and gefs members that saw something like that just not as extreme.  Gfs trended that way.

[Bob Chill]

2 hours ago, Isotherm said:

 

Yeah, there will be a -AO in the means, but that's generally an ineffectual signal when coupled with a poor Pacific and less than favorable NAO. A -AO contemporanous with low heights on the West Coast can work if the -NAO is stronger, which I'm not seeing for awhile. Like you said, it'll temper the torch and maybe offer some light events. 

I'm thinking more about rolling forward or retrograding the pac pattern while maintaining the -ao. Unanimous agreement with a bad pac for a time but my guess is things will shift by two weeks or so. If we can maintain a -ao beyond the the +epo period then the personality for winter in the east can shift in a hurry. Of course we could just repeat where we've already been and have the epo ridge return while the -ao disintegrates. Wouldn't that be fun....lol

[Bob Chill]

3 minutes ago, psuhoffman said:

Hmm so it's a long shot and it don't look like much at the surface, just a weak wave over the southeast, but get the vort at the base of the trough a bit more amplified and get it to cut off and suddenly we have that EPS run I posted. That one was crazy but there were several EPS and gefs members that saw something like that just not as extreme.  Gfs trended that way.

Gfs trended a little towards what the euro did a few days ago with a slow moving + tilt trough and overunning connection. I suppose that's on the table still too. Trough would have to crawl to pull it off that way but the gfs made me think about it. 

[psuhoffman]

Ggem does it too. Huge shift at h5. If this were the final result we would be screwed. Clipper flies by to our north. Wave develops way off the southeast coast. But if this is a trend towards getting the northern stream out of the way and digging something behind it that's actually a better setup for us. Lot of time left. I didn't hate the change at h5. I didnt think the closed low to our north idea was gonna work. 

[cae]

Comparing the 12z and 00z GFS runs, it looks like we get a similar result (light snow) in two different ways.  in the 12z run, the trough dug more earlier in the run, resulting in the development of a surface low near NYC that gave us snow.  In the 00z run, it resembles more of a frontal passage.  Although the qpf is similar in our area, you can see the difference in the alignment of the heaviest axis of qpf near us.  You can see it more clearly looking at the qpf near NYC and Louisiana. 

PSU pointed out another way we could get snow out of this, with the crazy EPS member solution.  I think that's why so many hits are showing up in the ensembles.  For some reason, there seems to be a lot of different ways to get snow out of this setup. 

[Ji]

Hmm so it's a long shot and it don't look like much at the surface, just a weak wave over the southeast, but get the vort at the base of the trough a bit more amplified and get it to cut off and suddenly we have that EPS run I posted. That one was crazy but there were several EPS and gefs members that saw something like that just not as extreme.  Gfs trended that way.

You know the winter sucks when everytime you post your sentence starts with its a longshot.....

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[Rtd208]

 

[cae]

ICON made a similar shift as the GFS and GGEM.  A more elongated trough, weaker coastal low, but we still get light snow from an overrunning event.  Not as much as 18z though.

[RedSky]

39 minutes ago, Rtd208 said:

 

You know it's bad, really bad when they start rolling out the March will be rocking arguments. Nuclear spring sun snow sucks.

 

[AfewUniversesBelowNormal]

The Aleutian ridge showing up on long term models doesn't fit and probably won't happen. La Nina bias, or a lazy-run forward of the pattern the last 60 days. The cold is a little more established than usual. 

[psuhoffman]

11 minutes ago, RedSky said:

You know it's bad, really bad when they start rolling out the March will be rocking arguments. Nuclear spring sun snow sucks.

 

I don't disagree with the reasons many are floating the idea of a good pattern mid feb on. I see the probability we get tropical forcing back where we want it then and with shorter wavelengths and possibly a weakened PV the recipe is there. I'm just impatient and don't want to write off our 4 best climo weeks of winter. That said we have many a season saved by what happens after feb 10. Most recently 2015. If that's how we have to play it so be it. 

[psuhoffman]

1 hour ago, Ji said:

You know the winter sucks when everytime you post your sentence starts with its a longshot.....

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If you do what I said earlier and remove the 3 "good" winters from each decade in the last 30 years D.C. Averages 7.8" of snow in the other 21 winters. That's 70% if our winters. The vast majority. We average 7.8". The best in that whole group was only 13". Even if I only removed 2 per decade we wouldn't get a 20" winter in the bad grouping. That 7.8" number is what a normal winter is. The 2-3 good winter each decade are the aberration. Seems we're having a normal winter. D.C. is right on pace to end up between 5-10". Right where they should be 70% of the time. 

[psuhoffman]

Lol at euro. It's gonna do it or come darn close judging by the h5.  Pop the coastal southeast of us after the clipper goes by to the north I mean. 

[mitchnick]

Just now, psuhoffman said:

Lol at euro. It's gonna do it or come darn close judging by the h5.  Pop the coastal southeast of us after the clipper goes by to the north I mean. 

https://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=us&pkg=z500_mslp&runtime=2018011200&fh=144