psuhoffman

http://climod2.nrcc.cornell.edu/

Yea you are right... my post earlier was just trying to highlight why I agree with you.

no 1993 was one of the rare examples of a full latitude western coupled PNA/EPO ridge and a full latitude eastern N AMerican Trough that worked out. Got enough of the trough to concentrate and bomb a storm. This isn't quite that because there is a blocking ridge in Canada...kind of a mini mid latitude version I guess. The 50/50 has to vacate as the trough amplifies or else the storm cannot turn the corner. Actually one of the issues here (and this is good because its likely a GFS over amplified bias issue) is how the upper low cuts off and digs so far south...that slows the system down and leaves us with a southerly flow ahead of it for too long...it destroys the airmass and then we don't recover in time. If that upper low was a little more progressive and cuts off over TN instead of along the gulf coast its a win for us. I wasnt trying to dig too deep into analysis of a day 9 storm on an op run though...but actually if we assume the upper low isnt going to cut off down south of Atlanta like that...its probably a snowier outcome for us.

I don't buy it... I doubt that is exactly what the H5 will look like...but if it is...we should do ok.

I agree...but right now that lead wave has very little upper level support and its running into a wall of supression. It has very little chance unless we see some significant changes. Those can still happen its 6 days away. WRT the more amplified day 9/10 option...that GFS solution showed how it can work...just need the thermals to be a couple degrees colder from day 10. That isn't a big adjustment. The track is perfect. The whole setup will likely undergo significant alterations by then. If one of those is "colder" we could do well.

I will say this...I never look at the surface long range until last...if at all...and looking at the upper levels everything went exactly the way i wanted to see...then I looked at the surface and was like...WTF... but its 10 days away so who cares. But I do seriously doubt if we get a 967 low off Ocean City on Feb 1 we rain. The airmass leading in isnt that bad.

This is how we do rainstorms now...lol

LOL...988 in eastern NC, 967 east of Ocean City, 954 off NJ...and we rain. If that actually happens all the bunnies better be hiding...

GFS is a good run imo... verbatim its mostly rain but its a perfect upper and surface track... and its very close with temps...and that is going to be a problem no matter what in this pattern given the true cold air is locked up until we get towards day 15.

regardless of where The 12z GFS ends...this is what I see in the setup.... The only thing that would make this REALLY good...would be if that Canadian ridge were centered further west...that is the one thing that could much this up...if that allows too much return flow ahead of the amplifying system...if the 50/50 departs too fast...that could mess it up...but there is a LOT to like on this setup. And getting that ridge to be a little further west isnt a huge adjustment either...it could trend that way.

this could work on the GFS...the lead wave is squashed but the NS wave that squashed it has amplified enough to leave a lot of cold air and still a decent amount of confluence to our north leading into the next wave...we will see. I shouldn't predict how a run is going to go...never ends well.

@Ji @Bob Chill That little vort losetoa6 was talking about the other day as something to watch behind the weekend rain storm is going to suppress the lead STJ wave next week it looks like. It's there across guidance and its getting absorbed into the vortex left behind by the weekend rainstorm and suppressing the flow way too much the middle of next week. What we would need if that is the progression is for that wave to amplify enough to hold the confluence in to our north for the next wave coming, and there is a next wave...its a train coming at us...we just need to time one of these things up right...the goldilocks timing...close enough to an exiting NS wave to our northeast that cold has not vacated...but far enough back not to get squashed. OR...get the NS to phase just right...but we all know the complications with that.

The ICON could still work out...it is much stronger with the confluence and it still has a decent amount of confluence and NW flow to our north at 180. Plus the northern stream is digging in pretty far east...not too far east to develop in time but far enough to make a hard cut unlikely imo. It actually is setting up for the win option number 2. But now we are extrapolating the 180 hour ICON...lol. Its forever out there...the bottom line remains there are realistic ways to win with this and that is way better than it's been most of this dumpster fire winter.

Everything is trending that way unfortunately... remember wave 1 is the one that 36 hours ago was cutting north of Green Bay. It has been trending weaker across all guidance lately. And it is running into a lot of suppressive flow. That ridge near Hudson is a double edged sword...it is going to force things south despite the raging +AO BUT the reason I would rather it be on the west shore of Hudson Bay is that would allow more room to amplify a system along the east coast WITHOUT needing the NS to dive in and phase. With that ridge where it is...I kinda fear without phasing a weak system will shear out or get suppressed south of us...and the risk with needing NS help is it could just as easily (more likely) phase too far west and cut the storm. But...if it does phase right...that option has big storm potential so there is that.

There is some agreement beyond day 10 with where we go into February. Across all guidance there is consensus for a PNA driven +AO eastern trough pattern. Details differ at day 15 (as they always will) but the general longwave pattern is agreed upon. Doesn't make it right...but confidence in something at least similar to this is increasing imo. This is not the best look for snow...but it is way more workable than what we have had so far. The GEPS would be the coldest look...but also the least likely to produce a snowstorm probably. Clippers maybe...but while this is a cold look...true cross polar flow here...the trough axis is way too far east and historically a huge full latitude PNA/EPO coupled ridge is a cold/dry look in the eastern US. Way too hard to get something to amplify in that. Now some of the examples where something did manage to develop in that they can be huge storms. March 93 was an example...but 90% of the time that look ends in a cold dry period. The Euro is still hanging on to the AK vortex but has enough of a PNA ridge along the west coast to direct the trough into the east. This is not as cold...its not true cross polar flow...but that flow out of AK is good enough. That vortex there is going to be producing some pretty cold air near AK and getting some of that to eject into the eastern US will be cold enough in early February. This is not as cold as the GEPS but still plenty cold enough to get a snowstorm and the trough axis here is way more favorable. It's still not a look worthy of "its happening" but its a workable look. The GEFS might have the least cold but best look for a snowstorm. There is just enough flow from AK into the east to get enough cold...but that ridging over the top and in the southwest produces the best look to get a storm to amplify in the east. Ideally get that ridge a little north and pump the SW ridge a bit more and it becomes a classic look. The details wont be determined for a while...but if we can at least get the general ideas agreed upon across guidance February could be a lot more hospitable for snow than January was. Of course that is about as low a bar as possible.

The day 7-10 period could work. The setup that gives us a shot is only 6 days out and across guidance. The subtle but important differences to the setup now for this weekends fail are clear. For both the AK vortex isn’t doing any favors. But right now that vortex near Baffin (that wasn’t supposed to be there from range) forced the ridge in Canada to slide way too far southeast The result as the system develops in the central US is the flow is straight out of the south everywhere east of the Mississippi. No resistance or confluence until well north. Combined with the pac flow feeding maritime air into the ridge from the west and it’s game, set, match. but the setup next week has more promise. @Bob Chilldid an excellent job picking this out before guidance lost then found the idea again. this time the virtex has vacated Baffin. The ridge has pulled back towards Hudson Bay, and the trough near 50/50 is holding the NW flow and confluence to our north. We still have the AK problem so this won’t be a cold pattern and ideally that ridge would be slightly further west but it gives us a fighting chance to be just cold enough. From there we are in the game but still need luck. The lead wave amplifying before the cold vacates would be best. If the lead wave fails to amplify then we need luck with the northern stream digging in. It would have to amplify far enough southeast or the storm either cuts or develops too late for us. The fail option would be a weak lead wave that is suppressed south and fails to amplify enough to hold in the NW flow to our north. The cold lifts out and wave 2 cuts. The win is either wave one amplifies before the confluence breaks down, or if it is the second wave we get the NS to dig in and phase just right. Option 1 is simpler. Option 2 is less likely but holds more upside. As always the fail option is most likely. We all know that. It’s our reality. But this had a better chance than most of the lottery level long shots this year.

I don’t mind clippers at all. And sometimes they can really put down good totals up here. There were 2 in the 2000s that dropped 6” up here. Plus to get clippers the northern stream has to be pretty far south so it’s at least usually a cold pattern and often those clippers came before or after bigger storms. In Nina years with no STJ often those are all there is. But we haven’t spent enough time in cold patterns lately to get many.

Gfs has way too much going on to even think it has a prayer of being close to the right solution. But the period officially got my attention now. Goodnight.

A descending qbo, IO sst, shortening wavelengths all would suggest increasing chances to break the pattern as we move later in Feb or March. But beyond that I would be lying if I pretended to have any concrete insight. That PV has been a beast and isn’t going to give in easy.

Not if you move to northern New England.

So long as that wall remains up across the arctic no pattern in the mid latitudes can get that cold. But perhaps maybe cold enough with luck. Lots of luck.

I wish you luck. I do think we will have a few more opportunities to snow. I’m not yet resigned that DC ends up with a total skunked season. But odds of a “good” year are increasingly dwindling.

I get where you’re coming from. But part of using the guidance effectively is correcting for biases. The guidance won’t be perfect from range. It’s also incorporating climo and historical reference with the NWP guidance. The most logical correction right now is to assume the gfs is over amplified. But you are correct that could be a mistake. And that’s why forecasting long leads is low accuracy. But at day 8 we really shouldn’t expect that level of accuracy. Right now we can say with some confidence based on guidance that there is likely to be a system in the east day 8-10 with about seasonal temperatures that is likely a rain or maybe snow threat. That’s good enough. A day 8 forecast shouldn’t be more detailed. Exactly how strong isn’t necessary.

It’s ok, you can use my name.

The main difference is the depth of the system in the southeast. But all the guidance agrees on the main players. AK vortex. +AO. +NAO. Southwest ridge connected to a ridge across Eastern Canada. Trough in the southeast. That’s amazing agreement for that range. You’re stuck on specifics that should not be looked at day 8-10. Plus if you correct for the known bias of the gfs they look remarkably similar.