psuhoffman

After that...where we go into Feb really depends on what happens with the TPV. This look is universal across guidance at day 15 The CFS and Euro weeklies both agree on how this evolves...the extension of the vortex near AK lifts, the ridge under it builds up into the EPO domain...and this dumps cold into the CONUS and centers a trough in the Ohio Valley. This is actually a good look...look at the EPO snow mean in the climo thread. However...the long range guidance is suspect and if it is wrong about the vortex lifting near AK...this is an alternative progression if the vortex remains anchored the way it is day 15 and the NAO remains positive (and NOTHING indicates it wont). The analogs to the day 11 look are split between how that evolves with about half going the way the weekly guidance suggests...and half going the "gave over" way above. So...I guess the question is...do ya feel lucky?

The day 10-15 window still looks workable. This is from the 0z EPS but the look across guidance is similar Ideally we would want a little lower heights near the blue x and the ridge centered near the red x...but those are not big shifts for that range...and that is being really picky. This has flaws...this is not a cold pattern, the extension of the vortex into AK is cutting off any transport of true arctic air into the US, and the likely problem here is temps. But mid winter...we can sometime overcome that with a good track and marginal temps. This is about as good a pressure profile as we can get for a day 10-15 period. And the snowfall mean shows where the chance of snow is during this period...again temps are the possible issue It's not a perfect or great look...but its not the worst and we have lucked into snow in this look before. Just need some things to break out way this time.

Wanted to explain what happened to degrade our chances of snow next week. Barring a shift in the north atlantic pattern (and I touched on that yesterday) next week is looking very unlikely to produce snowfall. The guidance miscalculated what happens with the vortex in the north Atlantic the next few days and that sets off a negative chain reaction for our snow chances. From 7 days out the guidance actually nailed the current look pretty much. They might not have had the WAA EXACTLY where it will be...but missing a discreet detail like that by only 100 miles from 7 days away is NOT a significant error and well within acceptable range. Sucks for us but...what happens after this was due to an error in one major feature. Below is what was supposed to happen...That atlantic vortex was supposed to slide across the atlantic, the "storm" this weekend would move into its place...and the flow over the top of that would pump the ridge over Canada and end up centered as shown below. But that isn't what is happening. Instead that Atlantic vortex is going to phase into the TPV over Greenland...strengthening it and anchoring it over Baffin Island...that then also absorbs the storm this weekend up into it...creating a vortex that was not supposed to be there over Baffin...which alters the flow forcing the ridge to shift further southeast...and be centered over the Northeast instead of near Hudson Bay. So we end up with this look....instead of a ridge centered back in Central Canada. That of course shifts the trough well off the east coast. One major miscalculation in a significant feature in the north Atlantic degraded our chances of snow severely. Of course right after I post this the op euro says...wait a minute. There are enough random runs within the ensembles and an occasional op run...that manage to bring down heights to our northeast enough...(as I touched on the other day) that the threat is not completely dead. But it's unlikely IMO... it would need to overcome the ridge being centered too far southeast of where we want it. But guidance could trend back the way we need it...but as of right now the look above is why what was a very good look 5 days ago became mediocre at best.

@C.A.P.E. The solar correlation isn't as simply as some think. On top of what that study showed, which is at times the correlation between solar and NAO have flipped, during the last 50 years there seems to be an opposite effect based on the QBO state. The impact of the QBO on the PV seems to change based on the solar. Unfortunately this year we had what we want during low solar, a descending transitioning QBO and it has yet to do us any good. Isotherm brings up some interesting factors regarding AAM that I honestly have not done much research into and therefore do not factor into any of my calculations. But what I noticed when I did look into his points some... was that the current state of some key circulations are opposite of what we would historically expect given current ENSO and other SST anomalies and indexes. Things are out of phase...and perhaps that does explain some of the odd responses. Like he suggests, some of these other factors being out of phase with what would typically be expected with a descending near neutral QBO in a warm neutral low solar...could be countermanding the typical response to such a state.

Naw at the end it’s heading the same way the eps and weeklies are. And that’s not bad. But it sucks we might have to wait. Sucks more if it’s wrong and the op gfs is how this goes...

The only saving grace there would be hints the NAM state is flipping. Build the heights more over the top into GL and displace the trough out of the high latitudes and it could get better. But by then it’s mid Feb. let’s just hope that run smoked some funky stuff.

I mostly missed that Jan storm. My 2 biggest snows were the November snow and the March one. But your point is legit. I liked 2018 better though. The 6” in mid December was nice and kind of a surprise. There was a super cold clipper storm in January. One half decent snow in February and then I ended the year with a bang in March. 3 accumulating snows and one of them 14” that stayed otg a week even late March . I ended that winter feeling really satisfied. I had almost identical totals both years but last year felt “empty” for some reason.

It’s an op at super long range but the gfs is the biggest disaster I’ve ever seen at day 15. Just over 24 hours ago was that epic double hit snow run. This one has no more chance of being right. Let’s hope

“Whiff again?” What exactly are you chasing? March 2018 produced a warning level snowfall. Last year was a near normal snow year with several snowfalls. So what is the “again”? Or do you mean you are chasing the rare winter like 1996/2003/2010/2014 when it snows easy and often. If so yea this probably ain’t it. But is there a good chance it will snow again some this year...yea. Some of us are chasing that.

March 2018.

Cfs says mid Feb is worth waiting for I mean it has to be right eventually

No it was a nice run imo. Would give us opportunities for snow in February for sure.

Very nice weeklies run fwiw

I don’t put a lot of faith in anything past day 10. The EPS isn’t great but it’s a small adjustment from either good or bad. There will be adjustments. We will see.

How’s the fog?

It is. So that says our chances for snow are about normal, which for us isn’t very good. Lol however hidden within that are 2 facts...most of that comes day 12-15 from a specific threat. So that specific time period has some promise. And the pattern is mediocre but a slight adjustment from good. It’s not the same as a bad mean in a pattern with a ton of major flaws. That said it was a disappointing last 24 hours with the EPS. It hasn’t radically shifted any features but imperfections within the pattern have shown up to limit the probabilities.

That's not true...but it was a pretty bad run. It really goes crazy with the ridge in the northeast day 7-11 and its lights out on any chance there.... then there are a scattering of hits in the day 12-15 range but nothing to the level of the GEFS and GEPS. The pattern looks close enough to workable that it's not out of the question something changes and we sneak a threat in but the last couple EPS runs have not been friendly.

GEPS and GEFS both like the idea of a snowstorm somewhere in the mid Atlantic day 10-15

the op euro is a total dumpster fire disaster, but its just one op run at long range so.... But it does EVERYTHING the opposite of how we want... doesn't phase the ocean storm next week and slides out out, then washes out the day 9 threat completely so it doesn't amplify...crashes energy into the west and sets up a full latitude western trough eastern ridge...and leaves us in a total dumpster fire day 10. LOL

How much snow did you get last week?

The overall look day 10-15 is about as good as we can ask for on the GEFS There is definitely high pressure heading into the day 10 threat...we just need slightly lower heights near 50/50 to hold it in... After that...this is an excellent looking pressure profile...temps...and precip for an east coast snowstorm...

I would not totally give up on the day 10 threat until its into the medium range. There is an obvious issue...the cold is very stale by then and with the amount of ridging in Quebec...if there isn't enough of a 50/50 to keep confluence and resist the southerly flow ahead of the trough we will torch. But...there are vorts flying around and some do end up in a spot that could help...but the majority of the guidance says they either don't amplify enough or are not in the right spot at the right time. One way to really increase the chances is if the ocean storm next week phases with the NS and gets pulled up into the 50/50 location. That would change the equation and guidance would flip to a colder solution right quick. But its not a high probability ATT. After that all the guidance opens a legit window as whatever happens better or worse with day 10 they all agree that wave WILL amplify and knock down the ridging to our northeast and create a favorable window behind it with a pretty good looking trough axis and ridging across central Canada. It's the best look we have had yet for a legit snowstorm. Of course that isn't saying much...its a pretty low bar.

The overall pattern looks ok. The day 10 upper level energy actually gets forced under us despite being in the upper midwest cut off... that shows the effect of the blocking regime in Canada...problem is it scours out all the cold first...the Ocean Storm doesn't phase this time and so it slides out too far south to impact the flow and thus the southerly flow ahead of the trough torches our temps. The storm is forced under the blocking but it doesn't matter. Details in the longwave pattern matter. After that is when we have a real shot according to all guidance. IF the long range guidance is close to right there is a legit good window day 12-15 and the GFS almost is a hit but the system is disjointed and fails to come together...too much NS interference and a sloppy phase. That would be a supreme example of "bad luck" in an actual very good pattern.

@frd BAMWX is focusing on energy, and that is almost entirely temperature dependent...and given the recent bias and the look of ridging across canada cutting off cross polar flow...I would lean normal to slightly above overall also. But we are mostly hunting snow which is much different. We don't need an arctic dump in mid winter to get a snowstorm.

about 20% of the time we get lucky and some anomalous feature dominates the winter pattern in a way that makes it favorable for snow here. Sometimes its the NAO (1996/2010). Sometimes its the EPO (2003, 2014). It is becoming obvious this is NOT one of those years. The rest of the time the pattern is flawed and we will scrape and claw to get any snow and if we are lucky a couple times the winter is at least decent with a couple snow events...or if we fail to get lucky they can end up total dumpster fire years like 2002. Keep in mind even 2002 had a great period of NAO blocking and a few threats that just didnt work out, one got suppressed, one was slightly too warm in the boundary layer in the coastal plain, one just didnt come together and ended up the only small snow event of the year. With some luck we get a couple of those to hit and we remember 2002 like a lot of other typical mediocre winters. On the other hand 2000 had one good period over 10 days where 2-3 storms hit depending on where you were...but only one was really big in 95. What if that one storm did get suppressed like the guidance thought? We would remember that like we do 2002. If this is not going to be 1996/2003/2010/2014...and its probably NOT, then we are going to have to deal with flawed patterns and hope we get lucky a couple times to eek out a mediocre year with some snow. That is just how it is. And that is how it is most of the time.