Cobalt

Surprised WW didn't post this, the EPS actually upped the ante on both waves, with a bit more of an emphasis on wave 2. Odd that none of the operationals have done much with the 1st wave lately, because the EPS and GEFS have been keeping it somewhat alive (I would separate the two but I am running out of upload space)

13-14 sticks out to me as the one major anomaly on that list.. why did that winter end up so uncharacteristic at h500 and at the surface? Was it purely a fluke or the fact that the base state was already in transition to a more Nino look as followed with 14-15?

Now's the time of the year to start playing the game: Where In The World is DC Being Outsnowed? This time around it wasn't hard to find an unassuming location.

It was really at onset with poor ratios and some rain/sleet before snow took over. Once the coastal got cranking things cooled off pretty nicely. Of course there were concerns at the fact that it was in the 60s the day prior, but we know how rates can overcome almost any surface temp issues.

GFS had been hinting at that storm for days, but it wasn't until 36hrs out that all the models latched onto a WSW event all the way into DC. Euro went from 0.1" -> 1" -> 7" for DC in a 2 run span from 12z on the 1st to 0z on the 2nd, and the GFS had been hammering home the idea of a narrow swath of 12" for some time as well. Nobody believed it due to massive temperature issues at onset, but crazily enough, it verified and then some. That two week stretch of winter weather is close to one of the better ones you could ask for in any winter, back home I recorded 13" in just 2 weeks from 3 separate events. It's unfortunate that winter fell off of a cliff after that coastal bomb in late January (and still seems to be in recovery to this day).

So it looks like delayed, not denied on this tanking of the EPO, which begins close to the 25th, but peaks near the 27th-28th (so entering the short range). Impressive poleward ridging too. In fact, the Euro is so extensive with this ridging that it ends up intruding the AO domain near the end of the run, which is in clown range but has some decent ensemble support. Now I guess the question would be whether this EPO tank does what the previous two did not, which is produce snow potential in our area. Both the November 13th-20th and December 20th-27th periods saw average temperatures ~9-14F below average for all of the Mid Atlantic region, but the few events that took place during those stretches put us into the warmer sector of those systems. Hopeful that prime climo and that stout PV lobe can help get us on the board. I also recall reading that extreme November -EPO events were correlated with high latitude blocking returning later in the winter, so maybe we will see a return of that some time in mid-late February.

This certainly hasn't helped our prospects of snow recently. While the 97-02 snow drought didn't feature much of any notable cold in the CONUS during February, the recent 17-22 stretch has, it's just consistently been dumping into the Central and Western US, and the persistent SER has made it rather difficult to see any sustained cold in the East. This has turned what was a snowy month (avg 5.0") into just an average of 1.1" over the past 6 Februaries at DCA. January (4.9" avg during that interval), and even March (1.3" avg) have presented substantially more snow threats during this period by a good margin. Whether something temporary, exacerbated by persistent Nina conditions, or a product of the bigger picture, it isn't good, and has contributed to our futility since the 2015-16 winter.

I think it would be interesting to go back and categorize past snowfall events based on this criteria. From purely anecdotal evidence (and using what you've mentioned), it feels like 1 and 3 are happening less, but for whatever reason 2 might be happening more, or at least those events end up having more QPF than they used to. In just about every recent winter that has had at least some sustained cold (not just transient cold shots), those seem to follow. We got 1 or 2 of those last year, I can recall a few in 18-19, one in Feb 2016 (which dropped a surprise 8-12" in Stafford county), several back in 14-15, and so on. They're obviously not incredibly numerous, but I think those are events we're maximizing on more than we used to. They're replacing our bread and butter 3-6" events, and sometimes with more upside (like that one event in Feb 2015 after the brutal arctic shot where the track was awful but the cold was so entrenched that areas out near Leesburg got 10-14" before things warmed up enough). Of course the issue is that based on all of the data presented, none of that is enough to mitigate the loss of margins on the other two types of snow which in total likely add up to many more opportunities, but it is an interesting anecdote nonetheless.

Dulles looks to be the only airport that will challenge its warmest January on record, having a current monthly average of 43.9F, which places it firmly ahead of Jan 2006's avg temperature of 41.8F. As for DCA, a record warm January has been a long time coming, with all of the other "wintry" (Nov-Mar) months having their warmest average temperatures recorded in the 21st century (Nov 2001, Dec 2015, February 2017, and March 2012). Baltimore's warmest January on record stands at an incredible 47.4F set in January 1932, which is +13.1 in current 1991-2020 norms.

I think March 5th 2013 was one of the ultimate lows that this region has endured in terms of winter snowfall. I gave those old storm threads a read a while back to see what went wrong, and that storm bust looks like one of the first times you and others had opened a discussion about us losing margins on snowfalls that involved airmasses that might've worked a decade or two prior to it. Considering that the high temperature had topped out in 50s all the way in Saranac Lake, NY on March 4th.. yeah that was not a favorable airmass, even in March climo lol. I suppose details like that were just lost in the moment of insane snow outputs. But of course that was the beginning of the end of that historic snow drought, and 10 years later.. here we are It is actually crazy how relevant this post is a decade later. You, Bob, and others definitely called it.

In our most recent 30 year climo period at IAD, March was the snowiest month in a given winter season in 2018, 2017, 2014, 2013, 2009, 1999, 1994, and 1993. It's not incredibly uncommon for March to be relatively snowy for our general area, especially when compared to another month that is considered firmly in "winter" climo, December. If we're tracking in December, there's no reason not to track if things are favorable in March.

Jan 3rd of last year is probably the closest we've been to a a reverse bust of that magnitude in some time, considering that the Euro had 1-3" for areas that would end up getting 8-14" just 36 hours later, but not on the same scale as a KU that snuck up 6-12hrs before onset.. that will never happen again.

Just curious, what was the latest other winter that this one has now surpassed? I'm honestly surprised that 15/16 produced that early at your location as well.

This is true. If anything, it shows how lucky we were in the 13-14 and 14-15 winters. Without the major PNA/EPO help, this isn't far from being a pattern where we're on the wrong side of the gradient (possibly like what we're about to deal with in the D8-14 range):

It's crazy how DCA averaged just 18" during this stretch. Even with the 11-12 and 12-13 duds in there, that's one of the better h5 looks you could expect over such a long average. For reference, here's a stretch in the 80s where DCA averaged around 20". Definitely didn't need an insane +PNA/-EPO + cross-polar flow to pull that off. Of course the selected periods end up a bit arbitrary, but this is just meant to show two periods of similar snowiness in separate eras.

You had 50 inches 2 years ago and Texas froze to death. Winter can still be fierce thankfully Even in that month (Feb 2021) there was a ridge present off of the East Coast, so despite a -NAO and a part of the TPV entering the country, it was all dumped in the Midwest/Western US. There's definitely been quite the persistent SE ridge ever since the 2015-16 winter. Corresponding temperature anomalies show this as well Perhaps it is just a major extreme that will regress closer to the mean in the coming years, or a product of the warm SSTs. A stout favorable El Nino would definitely be a test of which teleconnections are truly running things around here.

"Winter is in a bit of a slump" is a funny way for Ji to refer to DCA's least snowy 7 year stretch in its entire history.

^ Hard to get substantial snowfall with sustained like warmth like we've seen so far this month. Moderately AN is one thing, but +10-15F seems more akin to November climo.

Would fit remarkably well with what we've seen ever since late Fall, with major -EPO spikes that precede a transient (albeit stout) colder regime in the Midwest/East, taking place every month or so. A similar tanking of the EPO happened close to the 15th back in November, another one near the 18th of December, and now it's plausible that a similar event will take place near the 20th-25th of this month.

72/73 was an example of a snowless winter that ended up bottoming out at 9F at DCA.. much like this one. That winter might've hurt more though, as it had the infamous Southeast storm in February.. I could not imagine the state of our subforum if something like that took place nowadays.

Heck of a cold snap taking place on the exact opposite part of the hemisphere.. it's like a Jan 2006 style month in terms of those temp differences. I believe that might've been a similar h500 pattern for us too.

This is a common fallacy. Around 10% of peer-reviewed papers discussing the future of our planet's climate in the 70s predicted cooling, meanwhile 62% predicted warming, and 28% had no stance. To be more relevant to this thread, you've mentioned record cold at local sites, but that has been over very short stretches. When just looking at the temperature departures for the past 2 winters across the CONUS, they skew pretty warm. And yes, there were several record cold days or even weeks, notably with February 2021, and a bit less with the chilly January 2022. The issue is that one cold stretch or even month doesn't make a cold winter, and when those major cold patterns haven't aligned, we've defaulted to being much warmer than average. This is obviously a small sample size but it was mainly meant to go over what you've said about the recent record cold. It's been mostly drowned out by warmer stretches taking up a majority of the rest of the winter, much like we're seeing now. Perhaps things will flip if we sustain a stretch of warmer ENSO years, but expecting cold and snowy seems to only work around 2-3 times per decade.

I need to find the graph that demonstrates this, but you could add this to the list of "positives" in the new base state. IIRC we are seeing more extreme -EPO events like Nov and Dec 2022 than we were 20-30+ years ago. As you've mentioned it tends to be a pretty weak signal of snowfall, but in non-nina years (the 13-14 and 14-15s), it can carry an entire AN snowfall season. In the end that would likely just mean that a given decade would have 2-3 PAC driven years, but mitigated by the fact that you'd also be seeing 2-3+ complete duds, with the rest in between (which is basically what we've seen during the past 10 winters). And as you've mentioned, cross-polar flow seems to be losing its bite too, so if we start to fail with even basic cold in those setups.. maybe it's time to find a new hobby in pouring copious amounts of liquid nitrogen into the Pacific ocean.