TSG

The whole start of this was around the statement that looking at analogs from decades ago may be somewhat worthless as the global pattern drivers are changing. You are arguing that N. hemisphere warming, which is changing those pattern drivers, has no effect on what we can expect in terms of winter weather in the Mid-Atlantic and that's just false. No one knows what the exact effects will be, but I'm not making that argument... Also, I pulled data for both snow and ice cover over the past ~40 years. The warming trend is clear and it's accelerating. It wasn't me looking at the past 5. That was frd.

I said sometime around 2006/2007 was the potential start of a new "era" and then explained why I felt that way with data. If you want to say I'm wrong in that opinion, back it up bud. Your anecdotal evidence that things haven't seemed to change doesn't count.

I'm not explicitly talking about sea ice either. I'm talking about the northern hemisphere warming overall which is undeniably happening whether you believe in AGW, or not. The Arctic sea ice extent is one way to look at that phenomenon as it is something we have solid data on for decades now. I'm not talking about what has happened in this tiny part of the globe the past 30-40 years. It's quite possible we're seeing the downstream effects of a less frozen artic 5-10 years later. Of course one bad summer for sea ice doesn't mean some part of the Northern hemisphere is going to have a mild winter... there isn't any connection that simple, but decades of accelerating trends tell a story. Do we know exactly what that means for our backyards? No. Can we identify that things are changing and have been doing so at a higher rate than previously recorded since a certain point in time? Yes. The Arctic is our source for cold and it's warming faster than any other part of the globe. If you don't think that's a sign that we can expect changes in what the average winter will be like moving forward, I don't know what to say. EDIT: Adding some snow cover data since that seems it'll get better traction here. https://nsidc.org/cryosphere/sotc/snow_extent.html

I'd argue around 2006/2007 was when we started into a new era. Arctic sea ice loss (an indicator of Northern hemisphere warming) has really accelerated since then. There's obviously not a hard line in the sand, and downstream effects are going to play out over longer timescales, but these two graphs below emphasize it pretty well. 2020 just landed itself as #2 lowest on record after 2012. Link here if you want to mess with the data: https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ 1997 - 2006 2007 - Present

Agreed. This is how I remember it and it's not even that early... October starts tomorrow. The upper elevations in Shenandoah are now starting to show some color based on my hike last Saturday but the understory is still very green with all the rain we've had recently. This was taken at about 3,000ft: http://imgur.com/a/6yx3gep

BWI: 10/30 IAD: 10/26 DCA: 11/7 RIC: 11/12 TB: 85

Looks like a Cat 1 outside in Woodley Park right now.

That might be my favorite app. Pro Tier 1 is well worth the money if you don't already have it. Tier 2 has a ton of cool features but it's $100/year.. too much for my needs.

Haven't those been mandatory since the mid-70s? They certainly made a big difference, but I think the improvements we've seen in the past 20+ years have much more to do with the 1990 amendments to the Clean Air Act than anything else. Those regulations targeted the big commercial and industrial pollution emitters.

Looks good, summer can end now.

I'm only in my late 20s and even I've noticed a huge difference in summer air clarity the past 5-ish years compared to growing up in the late 90s/00s. Code red and orange days were pretty regular and would often last for days in a row. That combined with mild asthma really made me hate summer sports. I can't remember a stretch like those recently though.

Cool summer inbound BWI 97F DCA 98F IAD 95F RIC 98F

DCA reported Mod Snow at the onset of precip. There's a sudden temp/dew drop, pressure jump, and then a subsequent rebound around the same time. What am I seeing here, computer error? Glitch in the matrix?

Finally under 30 in parts of the DC. 29/15