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Pattern General Wx/Pattern Disco

Rain Cold said:
I have suggested that while generally warmer temps probably aren't helping us in the snow department, the impact that climate change is having is, in fact, on the larger scale - that it is influencing something that creates a large scale environment that is unfavorable to supporting a -NAO and troughing in the east. But I don't know if that holds water or not.

Whatever is going on is blitzing us with -PNAs and seems to make it impossible to end up with temps below normal during the winter season, which obviously makes winter weather more difficult.
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I'm not a climate change extremist by any stretch, but I am on the front lines of screaming that no one, if they are being honest, fully knows the impacts on any of the scales (micro, meso, synoptic, global) it will have. Perhaps there has been a coupling that has resulted in this shift, perhaps it helps explains some of the changes observed in NWP evolution of events, or perhaps it's none of those.

I'll draw lots of clown emojis for this one (and probably deservedly so), but there was a time from when I was in grad school up until about 2021 where I had supreme confidence in my own personal winter pattern recognition forecasting. I could only recall maybe 2-3 events in 10+ years I felt I had really, totally whiffed on correctly picking out for our area (i.e. as legitimate or not legitimate) in the D7-D10 range, and since then, I think I've whiffed on probably six or seven out of eight setups (Jan. 22 being the exception) that I felt with confidence would produce and we've been blanked. My long range confidence in identifying favorable patterns that could produce snow in NC has never been lower. To channel @Brick Tamland, it does feel something has changed and the medium range trends in guidance that used to be stone cold locks don't matter anymore. It's not that the actual patterns that end up verifying are a surprise when they don't produce, it's how they are modeled in the medium range and then evolve or don't evolve are what seems to have changed. Maybe I've become senile in my late 30s, maybe I've lost my fastball, or maybe something has changed. I don't think I'm the only one who has experienced this though.
 
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Rain Cold said:
I have suggested that while generally warmer temps probably aren't helping us in the snow department, the impact that climate change is having is, in fact, on the larger scale - that it is influencing something that creates a large scale environment that is unfavorable to supporting a -NAO and troughing in the east. But I don't know if that holds water or not.

Whatever is going on is blitzing us with -PNAs and seems to make it impossible to end up with temps below normal during the winter season, which obviously makes winter weather more difficult.
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I agree. I believe it is indeed climate change that has flipped a switch of oceanic temps, SSTs, somewhere that has caused us to get into a rut in the pacific. Warming of the oceans, has caused a pattern change that we can't break out of. And we have yet to identify.

I love this discussion and thread though, trying to break down the why of our current situation.
 
1300m said:
I'm not a climate change extremist by any stretch, but I am on the front lines of screaming that no one, if they are being honest, fully knows the impacts on any of the scales (micro, meso, synoptic, global) it will have. Perhaps there has been a coupling that has resulted in this shift, perhaps it helps explains some of the changes observed in NWP evolution of events, or perhaps it's none of those.

I'll draw lots of clown emojis for this one (and probably deservedly so), but there was a time from when I was in grad school up until about 2021 where I had supreme confidence in my own personal winter pattern recognition forecasting. I could only recall maybe 2-3 events in 10+ years I felt I had really, totally whiffed on correctly picking out for our area (i.e. as legitimate or not legitimate) in the D7-D10 range, and since then, I think I've whiffed on probably six or seven out of eight setups (Jan. 22 being the exception) that I felt with confidence would produce and we've been blanked. My long range confidence in identifying favorable patterns that could produce snow in NC has never been lower. To channel @Brick Tamland, it does feel something has changed and the medium range trends in guidance that used to be stone cold locks don't matter anymore. It's not that the actual patterns that end up verifying are a surprise when they don't produce, it's how they are modeled in the medium range and then evolve or don't evolve are what seems to have changed. Maybe I've become senile in my late 30s, maybe I've lost my fast ball, or maybe something has changed. I don't think I'm the only one who has experienced this though.
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I know I've said this many times before and speaking of getting clowned, I usually do for saying it or questioning it. Anyway, could it simply be cyclical? I mean the amazing data sets that the SCO and you guys/gals are studying are really from the last what 100 years or so, most much less time than that. Is there truly a way to know if what we are experiencing now did or did not occur hundreds even thousands of years ago?
 
Metwannabe said:
I know I've said this many times before and speaking of getting clowned, I usually do for saying it or questioning it. Anyway, could it simply be cyclical? I mean the amazing data sets that the SCO and you guys/gals are studying are really from the last what 100 years or so, most much less time than that. Is there truly a way to know if what we are experiencing now did or did not occur hundreds even thousands of years ago?
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I think it could be to some extent, certainly. Obviously a warming background state plus increased urbanization doesn't help matters, but we've seen warm periods before any of that occurred that were followed up by colder, snowier ones, so I feel at some point (despite my negative musings earlier) we will likely transition to a more favorable background state at some point in the future and it's probably only then that we'll know the impacts of the things I just mentioned. Frankly, I don't think it would matter what century we were living in with the background state the way it is now as @SD showed.
 
Looking back the 1950s featured a similar pattern to what we have seen over the last few winters. The caveat was the 50s having a west based -nao while the last few were +nao.

Is this cyclical? Idk. But it's good to see history at least this pacific pattern isn't unheard of on a decadal time scale
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Just for fun this was the 60s

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I'd take that 500mb look for 10 years
 
SD said:
Looking back the 1950s featured a similar pattern to what we have seen over the last few winters. The caveat was the 50s having a west based -nao while the last few were +nao.

Is this cyclical? Idk. But it's good to see history at least this pacific pattern isn't unheard of on a decadal time scale
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View attachment 146741
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Only one above normal season for ten years in the 50s.
 
SD said:
Looking back the 1950s featured a similar pattern to what we have seen over the last few winters. The caveat was the 50s having a west based -nao while the last few were +nao.

Is this cyclical? Idk. But it's good to see history at least this pacific pattern isn't unheard of on a decadal time scale
View attachment 146740
View attachment 146741

Just for fun this was the 60s

View attachment 146742
I'd take that 500mb look for 10 years
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This is great stuff. And we have seen a shift towards Greenland blocking trying to return, we just need the cold vortex to move east again and the N PAC to realign. Who knows, we could have a decade of great winters staring us right in the face and don't even know it.
 
Not going to lie I'm concerned about the pattern going forward. Warm is the rule through at least the next 20 days but the strat pv is taking a massive hit and it may be undergoing it's final warming. If that happens this WC trough eastern ridge pattern may try to morph into a -nao and increase cold potential in the SE the last 10 days of March indy April. Given that we are likely to see at least some level of green up through mid march this probably isn't going to be great.

You can already see the gefs and geps starting to mess around in the NATL
gem-ens_z500a_nhem_65.png
gfs-ens_z500a_nhem_65 (5).png
 
SD said:
Not going to lie I'm concerned about the pattern going forward. Warm is the rule through at least the next 20 days but the strat pv is taking a massive hit and it may be undergoing it's final warming. If that happens this WC trough eastern ridge pattern may try to morph into a -nao and increase cold potential in the SE the last 10 days of March indy April. Given that we are likely to see at least some level of green up through mid march this probably isn't going to be great.

You can already see the gefs and geps starting to mess around in the NATL
View attachment 146746
View attachment 146748
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Like clockwork. The biggest shame is the fruit has had good chilling hours this year so it could ruin a much needed good crop.
 
1300m said:
I actually was just speaking to the NC climate office this morning and they found (unsurprisingly) similar trends statewide. I don't want to share their research without permission, but I can tell you they plotted rolling average annual snowfall for Asheville from 1995-2024 and it went from ~15" to ~10", Greensboro from ~11" to ~7.5", Wilmington from ~2.5" to <1", Charlotte from ~7.75" to ~3.75". However, they also agreed with me that this is more than just climate change. @SD is onto something with the large scale pattern shift. Folks don't want to acknowledge it, but the NAO has historically been a monumental driver of winter weather in the eastern US, especially NC. The absence of that combined with the N PAC ridge is a death knell to winter weather chances.

Again, and the SCO agrees with me here, if we were seeing a lot of cold rain events in the 30s or suddenly we were seeing multiple sleet or freezing rain events instead of snow events with a small, consistent warm nose, then perhaps you look at warming temps. But this is a large scale, seasonal winter patten shift.

It's possible when we look back in 40 more years we flip back - Greenland has already shown a significant increased tendency for blocking the past few winters, maybe we turn it on with the TPV getting further east in winters to come. I don't think anyone truthfully has any idea. If they did, I'm pretty sure everyone's forecasts wouldn't have ended up in the same place as mine this February (dumpster fire).
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I saw that you went 1944-1984 and then the last 40 years in your research. I’m just curious what the period from 1904-1944 looked like. I know there’s probably not as much available data, but I would be interested to see how some of the milder periods during that 40 year span effected averages… especially the 1930s
 
Chazwin said:
I saw that you went 1944-1984 and then the last 40 years in your research. I’m just curious what the period from 1904-1944 looked like. I know there’s probably not as much available data, but I would be interested to see how some of the milder periods during that 40 year span effected averages… especially the 1930s
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I had it saved on my computer already bc priorities but here you go. I changed the M's to .01 to make the autosum easier before someone asks.
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