psuhoffman

It's a legit threat. Not all longwave patterns are created equal. Not all -PNA's are created equal. A -PNA pattern without any blocking and a scorched N America with no cold air anywhere is never going to work, and that is what we've had when we've had a -PNA most of the time lately. A -PNA with blocking and a N America covered in snow and cold air left over could possibly work. Yes it will be a warmer pattern, yea any wave COULD end up rain...but at least there will be waves coming at us and room for them to amplify.

@Chris78 @CAPE we did need the pattern to relax some... the amount of blocking we had along with the +PNA -EPO was causing extreme suppression. The one significant precipitation event we've had in the last month came during a temporary -PNA. And this is not uncommon. I've said before that when I looked at every single 5"+ Baltimore snowstorm the majority of them did not come in frigid arctic regimes. And it becomes even more apparent if you just look at the 10"+ storms. There are several reasons for this. Big storms ride the thermal boundary and that means they are usually along the rain/snow line...not in the middle of an arctic airmass! We have to be somewhat near the warmth to win OR there has to be a wave amplifying enough to press the warm boundary back towards us! Waves don't amplify in a cold NW flow regime! There are some rare examples of super cold storms, we got one last week, but it requires so many rare things to time up perfectly...if that is the only way we get big snowstorms we would be in big big trouble. A lot of our big snowstorms came during periods that weren't that cold. Feb 83, Feb 87, Jan 2000, Feb 2006, Feb 2010, Jan 2011, Feb 2014, March 2015, Jan 2016 all came during periods that weren't arctic cold right around the time of the storm and most of them we even had to worry if it would even be cold enough! Way way way more of our big snowstorms come during "just cold enough" regimes not during our craziest coldest arctic airmasses. Those tend to be dry. We can luck our way into a frontal wave or weaker snow...smaller snowstorms are more common in these cold periods...and we've been perhaps unlucky not to get at least some of those during this latest period...but our true big snowstorms usually come during less cold periods. What's been especially frustrating over the last 10 years is a lot of the patterns that historically would provide us with chances of snowstorms...not cold but should be "just cold enough with a good track" ended up just too warm and when a perfect track system came alone it ended up a perfect track rainstorm. But that doesn't change the equation. It's been so long since we had a big region wide snowstorm during a pattern like Feb 2006 or Feb 2010 that it seems some are starting to think we need some big EPO/PNA ridge induced arctic airmass to get a big snowstorm but that's never been our typical path to a big snow. Most of our big snowstorms came during blocking regimes with a split flow under it and no arctic air anywhere (no NS to FCK up the flow) and some juiced up STJ wave came along with the perfect track and it was just barely cold enough to snow.

we had a blizzard what would have been presidents weekend 1958 but the holiday was still called Washington’s Birthday then.

If you think the lack of a blockbuster rare huge snowstorm Feb 20-28 is not just the product of a random chance distribution of a rare event over a limited sample then explain the causation. Finding some pattern in numbers means absolutely nothing if you can’t show there is causality and it’s not just an artifact or randomness.

Persistence works more than 50% but it’s not enough to just rely on it. just off my head these winters featured significant pattern shifts and storm track changes 1993, 1999, 2000, 2004, 2005, 2006, 2007, 2015, 2016, 2018, 2019, 2022

Where the warmest anomalies are changes exactly how the pattern sets up. A more west based Nino places the tropical forcing closer to the dateline which is where we want it. That tends to correlate with a trough southwest of Alaska...the downstream impacts of which are good for us. An east based nino shifts the whole pattern further east and often we see the north pacific trough end up too close to the Pacific NW which floods the CONUS with pac puke. We need that to be pulled back some.

Sometimes a QPF pattern persists all season...sometimes not. Remember 2015, Everyone thought we were toast when all those snows hit north of us through January and early Feb...then it became our turn from Feb 15 into March. That was maybe the most extreme example but it's hit or miss whether the a pattern persists the whole cold season...the problem with using persistence is it works until it doesn't and it's hard to predict when the pattern is going to change until it does.

The latest CANSIPS was indicating a possible modoki nino. That would increase our chances significantly.

It's true that we will lose the deep constant cold and enter a more variable period...but so long as we have blocking in February or March there is the threat of a snowstorm.

can we really call it a jackpot?

The humidity might rise slightly for a time.

Tracking clouds

So much here…We almost get a snowstorm 48 hours after this. On aigfs we do. And it’s the long range gfs.

There are some similarities to 2018 only in this case the TPV was weaker to begin with and the warming is happening about a week earlier. Obviously we will need luck to go our way...but if we got a similar pattern to March 2018 and got it to set in 7-10 days earlier AND with a colder N American profile to start... I would roll the dice with that.

Might take the kids to snowshoe