psuhoffman

Nope it’s degrading run after run as more members agree on a AK vortex with +++ NAO. It’s almost impossible to overcome that combo. The Hudson ridge is the only thing creating any slim hope.

I can understand that misconception. Let me explain how I analyze long range patterns... First of all there is a difference between macro and micro. Long range is macro...short is micro. I tend to look at things in 5 day chunks. Day 1-5 we tend to have pretty good reliability on the longwave pattern. Meso scale details can still change...but the broad pattern is pretty much known and we are analyzing specifics that might shift small scale things (those matter a LOT to snow...like where the back edge is, where banding sets up, will the track of the SLP shift 50 miles..) but are not really a longwave pattern issue. Day 6-10 the longwave pattern is somewhat known...but can shift around somewhat. Of course that means identifying specific synoptic level details within this range is risky...we can start to make educated guesses about what the small scale details MIGHT be in this range but they are open to shifts. Take this weekend storm for instance...the guidance nailed the general look from 8 or 9 days out...but exactly where the mid level winds were directed due to the exact sharpness of the ridge/trough alingment shited around about 100 miles. That shifted the potential for a thump snow from MD to central PA. That is NOT a significant shift from 8 days away! On the macro level the guidance was great. On the micro is was off 75 miles or so...but that is about as good as can be expected in this time range. We are looking for generalities here not specifics. Day 11-15...the outer edge of where we can glean any meaningful pattern clues...only looking at very macro level things...clues to the basic configuration of main pattern drivers...knowing that even that will shift around some. This is just seeing if there are any clues that some favorable features like an EPO ridge, -NAO, -AO might be likely. Any micro level details are completely impossible to tell at this range. Now how I apply my snowfall expectations to any 5 day chunk. In the last 30 years BWI has had 29 warning level (5") events during the period from December 1 to March 10th. That is when the vast majority of our snowfall happens. Odds are greatly reduced before and after. Obviously odds shift some within that window but not as drastically as outside it. That is 100 days a season or 20 5 day chunks. Over 30 years that is 600 5 day periods. That means...with 29 warning level events...the odds of a 5" snowstorm during any 5 day period from Dec 1-Mar 10 is 4.8%. That is our base state...about a 5% chance of a significant snowstorm. Using 5" as significant...I picked that because it is warning level. This is arbitrary but you get the point. So when I say things look "good" it could mean a 20% chance of a significant snow. Think about it...that is 4 times the "normal" odds of a snowstorm. That is good compared to normal. But 20% still means there is an 80% chance we do NOT get a snowstorm. Even in our absolute best looks from 10 days out...I would NEVER put our odds of a snowstorm above about 40% and even that number is reserved for the absolute best looks we have ever seen from 10 days like before the January 2016 or February 2010 storms. There is way too much at the micro level that can go wrong that you will not be able to see from that range. Plus...think about right now. This area will see "some snow" just not a snowstorm. But some places will get 1-2" tomorrow...and not far away north will get 3-6". And some places will get snow snow showers next week on the NW flow. But we are just missing a "real" snowstorm by 75 miles or so. The details that determined that could not be seen from 10 days out. The micro level details that make the difference between a snow in central PA and one here is not going to show up on a general longwave pattern look from day 10. On top of that there are other things that make recognizing a good pattern for snow different from "its gonna snow". The pattern could flat out shift from day 10-15. We know that. But even if it doesn't... not everywhere in the area will get snow. A storm could just miss...when you get missed by 50 miles that isnt bad pattern its bad luck. When the storm misses by 500 miles thats bad pattern!. Finally here are some examples of why you cannot pick out a snowstorm at long range, only identify patterns that increase our odds.... Here are two examples, one worked and one just missed us to the north with a 4-8" snowfall... This one was a 4-8" snowstorm in our area This one was a rainstorm Notice the scale is not the same for both...if you normalize the scale the key features are even more similar. But there are SLIGHT differences. This was a WAA setup in both cases with a nice 50/50 to lock in confluence to the north. But the one that worked the trough axis was SLIGHTLY further east...and the ridging in the east was slightly less...although the scale makes it look more different than it really was. Do you really think those slight differences can be picked up at day 10+? From long range both of those storms would look identical. Not until within 5 days would we see the level of details to determine that one was a 4-8" snowstorm for DC and the other was a snowstorm in PA and rain for DC. Here is an even more drastic example.... One of these was a big rainstorm nothing burger...and one of the worst depressing storms in history...and the others were all HECS snowstorms...can you tell which is the bust? Take a guess...and tell me why you think that one was rain and the other 4 were all historic snowstorms in our area? A B C D E The bottom line is those all look great....and the differences minor...and from long range the very insignificant micro level issues that caused one of those to be a nothing burger vs a historic snowstorm would not be discernible. At long range I am just looking to see if the basic pattern structure is favorable (or more favorable than the typical crappy 5% chance) for a snowstorm. The details that determine our fate come in the day 1-5 range. I hope this helps wrt how I look at and analyze patterns. Curious what your, or anyone elses guess (dont cheat and look them up) is with those storms.

Vermont still looks good overall... These ratio's can sometimes be a bit high... Rutland is in a valley and will get less than the mountains around...but that is true of almost all the towns. I would expect maybe 4-8" in Rultand...with 8-12 up near the ski resorts. But like I said its only a few miles up to Killington from town. Another option...there seems to be a consistent area of enhanced snowfall in southern Vermont just south of where you will be due to added moisture from the flow over the lakes. You could take the drive south on 7 to Manchester or Bennington. Manchester is about 30 miles or 45 mins (in good weather) south of Rutland. I know there are some shops and restaurants in Manchester. I haven't spent a lot of time there though...but it has some low key tourist attractions. I know next to nothing about Bennington, only ever passed through on my way to ski resorts. It isn't close enough to them to stay there. But both will likely do better due to being under that enhanced band. Stratton Ski resort which is at 3900 feet in south central Vermont looks to be a likely jack zone. There are some little towns in and around Stratton up in the mountains there also. The good news is I have been in Vermont during some epic snowstorms...2 ft plus...and you can get around. Because the ski resorts are important to their economy they keep the roads pretty good even in the middle of a blizzard. By their standards a 6-12" storm is NOTHING so if you want to get out and about you will be able to get around...just don't rush and be safe!

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.

I don’t like to disappoint

Every time a threat fails or a pattern degrades some variation of the “I told you so” posts start. Except almost no one thinks snow is likely here. Even when the pattern looks “better” often that just means we have a 25% vs a 5% chance. Most here know our climo. We’re just tracking for fun and knowing every once in a while we get lucky. Telling us told you so is like saying “haha” every time you don’t win the lottery. Oh you told us so? Really. Thanks Nostradamus, really went out on a limb there. Those people look smart 80% of the time until it finally does snow then they look stupid. Of course they disappear when that happens.

I could make a generic forecast like that and it would be right 80% of the time. But thanks for reminding us what normal is around here.

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.

@losetoa6 also...get enough lift and suddenly you create a feedback loop. Warm air is lifted, cooling and condensing causing heavy precip which sets off dynamic cooling processes and mixes colder air back down countermanding the WAA. That’s when we get “the thump”.

It all comes into play but the main driver for WAA is getting enough mid level winds aimed at the cold over us to create lift. If the winds aren’t adequate it just slowly displaces the cold without really creating enough vertical velocity to create heavy Precip. The mid levels are important because that’s where the snow growth zone is.

the main mid level flow is still aimed NW. No getting that back. But that kink on the nam also associated with a little lead wave of vorticity is what’s responsible. It’s thete on the other guidance too but not nearly as distinct. That could save us from a blah event. Or the nam is just being the NAM.

March 2018.

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

Years ago there was a report they actually were measuring at a location surrounded by concrete where nothing would accumulate basically anytime there was no road accumulations. But I can’t verify it and I think I remember there was a dispute of that report. That would explain a lot though.

Just like anywhere else elevation matters. I’ve been in Killington/Rutland for snowstorms several times. Last year I was there and Rutland got about 10” and Killington had 18”. Few years back Killington got 24” and there was about 12 in the valley. Just how it is. But it’s only a short drive up from Rutland so you can spend all day up at Killington to catch the “show”. They have some nice restaurants and bars up there. Don’t know what you’re looking to do. I would definitely take the trip up Sunday to Montpelier and Stowe. Nice drive. And they will get more snow. It’s climo. They almost always do in a storm tracking this far north. Plus Stowe will get upslope snow behind the storm. You can take the Ben and Jerry’s factory tour right outside Stowe. Another option is to check out Stowe during the day and stay at Burlington. Short drive. It’s in the valley and won’t get as much snow but it’s an awesome college town with a lot to do at night. Would be a cool place to spend the last night before heading home. Montpelier is a smaller quieter town but I’m sure you can find a bar anywhere. Just depends what you’re looking for. One last thing...if you do go to Stowe make sure you drive up the access road to the ski resort. Sometimes there is a significant difference in snow. Worth the 5 miles. I hope you have a great time. I’m taking a mini trip myself. My sister is watching the kids so I can take my wife to a little B&B in Gettysburg for the night.

He isn’t wrong though. If it did set up there more than a few days...barring a dramatic flip in the NAO, it would flood the CONUS with maritime pacific air and we would be in big trouble. But I don’t think that’s where the pattern is going right now. It looks transient imo. But if it’s not... When people make conditional statements that’s not the same as them making a predictor. He didn’t say February is screwed. He simply stated a fact that “if” the vortex sets up over AK “then” February is screwed. It’s a conditional statement and it’s accurate.

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

I don’t think it will stay there. To me it’s a transient look as the vortex traverses AK as an epo ridge establishes itself. That’s my guess given what the trop pac forcing looks like week 2. It looks ominous simply because it’s at the end and so we can’t “see past it”. But just because we dont get a dumpster fire pattern doesn’t automatically mean we get a great one either. But I don’t think it’s heading towards a permanent AK vortex pac puke pattern Before that I don’t share either extreme view. We likely get warm after the cold shot next week as the Hudson Ridge drifts too far south and temporarily links up with the mid latitude ridge. But there are ways the look could reasonably shift and suddenly be better. If the ocean storm next week were to phase with the NS and pull up into a 50/50. Or another yet unseen vort bombs into that space. The wave break from such pumps the ridge over the top and suddenly we get the colder look of some sporadic runs recently. It’s unlikeky but it’s one rather insignificant change in the longwave pattern that has a drastic effect. Another option is the day 10 storm helps to knock down the ridge to our northeast and sets the table for a threat day 12-15. There are ways to avoid a disaster within the look we are getting. But it will involve some luck. It’s flawed but not no hope.