Feb Long Range Discussion (Day 3 and beyond) - MERGED

[psuhoffman]

8 minutes ago, clskinsfan said:

Euro was lining up for another hit at the end of the run as well. Like I said yesterday we are gonna get hit twice before February. 

That’s the one that has the best chance actually. And yea @stormtracker I know it’s day 11 but it’s about the progression. As everything retrogrades once the western trough backs off there is a window there with the blocking over Canada for something to amplify in the east. After that Feb depends on whether the AO stays negative. If so I’ll take my chances recycling the same general pattern but with a colder base state going in.  Maybe that works out. If the AO flips we torch. 

[psuhoffman]

9 minutes ago, Ji said:

Sorry but that won't cut it for me

Sent from my SM-G981V using Tapatalk
 

Better let someone know 

[jaydreb]

12z EPS snow mean down from yesterday’s run for next Mon-Tues but definitely supportive of a light-moderate event.  EPS does not support GFS solution of running the low into the upper Midwest.  It actually tracks the low across a pretty good path for us and keeps temps colder.

[jaydreb]

EPS also really likes the last week of January, after the Mon-Tues wave.  
 

EDIT: Sorry, this is 0z.  
 

 

[Ralph Wiggum]

2 minutes ago, jaydreb said:

EPS also really likes the last week of January, after the Mon-Tues wave.  
 

 

That period holds the best potential of the season thus far without question. You can do a loop of the eps ans see exactly how the pattern is progressing and repeating itself between the 23rd and last days of Jan. 

[Subtropics]

40 minutes ago, psuhoffman said:

I liked where the euro was going wrt the whole pattern day 10.  Details at that range don’t matter. 

When was the last time a day 10 materialized. I wouldn't get excited yet from this. We don't even know if this depicted will be remotely close to what happens.

[TowsonWeather]

2 minutes ago, Subtropics said:

When was the last time a day 10 materialized. I wouldn't get excited yet from this. We don't even know if this depicted will be remotely close to what happens.

Wait wait...you're saying a 10-day + OP might not evolve as depicted?

This changes everything.

Did y'all know that?!?

Man...this is blowing my mind right now. Thank GOD you were here to share this!

[jaydreb]

EDIT: Posted wrong run.  

[cbmclean]

2 hours ago, psuhoffman said:

 

Agree wrt Nina. The last few years weren’t a Nina.  The pacific problem has been the same regardless of enso.  And frankly we’ve barely had any Nina mid latitude pattern response this year. 

@CAPE but what is the right pattern?  If we have a PNA western ridge there will be a trough off the west coast directing mid latitude pac puke into North America.  Historically that worked so long as it wasn’t a full on vortex over AK because the puke mainly gets directed up and over into Canada and mixes with the cold continental air and the result is it’s not cold but not a furnace and just cold enough to get snow here  But the last few times we tried that the pac jet was too strong and it completely obliterated cold to our north.  Ok so that don’t work anymore.  
 

But what else does?  If we put that ridge off the west coast as an epo ridge because that ridge will be elongated SW to NE (again stronger pac jet and central pac ridge base state effect) it will dump a trough into the southwest.  That hasn’t worked because it pumps a ridge into the east (and news flash the Caribbean/gulf/Atlantic are on fire also lol) and the heat it picks up there pumps a huge ridge.  We thought with a block it would (should) but if, and I do mean if because it’s not close to done yet, that doesn’t work then what?   And relying on the incredibly rare epo NAO ridge bridge block combination isn’t going to save us often.  That’s a super rare look. 
 

So where do we want the ridge/trough alignment out west exactly?  If a pna and an epo doesn’t work?  Yea if we somehow got the once in a blue moon rare broad epo and pna ridge...but that’s even more rare then a epo NAO ridge bridge.  That’s not a typical wavelength.  The epo and pna are typically opposite. If you get a ridge in one you likely get a trough in the other.  And frankly it’s made even less likely with a faster pac jet, and that combo was super rare to begin with. 
 

Our best bet is as everything retrogrades because there was an epo ridge ahead of it and some cold got in, and as the pattern shifts back to a trough in the northeast pac there will be a window before the cold gets blasted out of North America again with a trough in the east. But that’s a temporary window that took weeks if factors going in an intricate progression. I fail to see this golden pac pattern that leads to a permanent snow friendly regime here if a +epo/+pna/-AO/NAO (what we’ve had for 6 weeks!)  doesn’t work anymore. 

The last significant cold outbreak I remember in my neck of the woods US was late December 2017/early January 2018.  Not much snow up you guys way but it was 2 weeks of solid cold.  I am assuming that it was Pacific driven.  I took a look at the 500HP anomalies from that period and it didn't really make sense to me.  Would you be interested in analyzing that period to see what was going on?

[anotherman]

The last significant cold outbreak I remember in my neck of the woods US was late December 2017/early January 2018.  Not much snow up you guys way but it was 2 weeks of solid cold.  I am assuming that it was Pacific driven.  I took a look at the 500HP anomalies from that period and it didn't really make sense to me.  Would you be interested in analyzing that period to see what was going on?

I remember it well. Susquehanna froze over completely. Legit cold for a significant period of time.

[cbmclean]

6 minutes ago, anotherman said:

I remember it well. Susquehanna froze over completely. Legit cold for a significant period of time.

Ponds froze over and I hit 0 °F in Wilson NC, which is in the coastal plain.  That is amazing for here.  Back then I had even less knowledge of global weather patterns than I do now, so I wasn't really paying attention to what was driving the cold.  Now I want to understand.

[anotherman]

Ponds froze over and I hit 0 °F in Wilson NC, which is in the coastal plain.  That is amazing for here.  Back then I had even less knowledge of global weather patterns than I do now, so I wasn't really paying attention to what was driving the cold.  Now I want to understand.

Pretty sure it was a -EPO. Dry but frigid.

[WxUSAF]

1 minute ago, anotherman said:

Pretty sure it was a -EPO. Dry but frigid.

I think so. I remember we were stoked for an overrunning pattern from D10+ range but then the cold just pressed farther and farther and we had a cold and dry couple weeks. 

[psuhoffman]

19 minutes ago, cbmclean said:

The last significant cold outbreak I remember in my neck of the woods US was late December 2017/early January 2018.  Not much snow up you guys way but it was 2 weeks of solid cold.  I am assuming that it was Pacific driven.  I took a look at the 500HP anomalies from that period and it didn't really make sense to me.  Would you be interested in analyzing that period to see what was going on?

 

4 minutes ago, anotherman said:

Pretty sure it was a -EPO. Dry but frigid.

 

2 minutes ago, WxUSAF said:

I think so. I remember we were stoked for an overrunning pattern from D10+ range but then the cold just pressed farther and farther and we had a cold and dry couple weeks. 

If I recall the genesis of that arctic outbreak was mid December when a crazy epo ridge that even pinched off into a block near AK for a time went up. It dumped a ton of cold into Canada. Initially western Canada as would be expected with a epo ridge. Then late December a pna ridge went up temporarily and pressed the cold into the northeast.  By January the pattern was a convoluted mess as the pacific shifted but the cold was left to linger over the east another 10 days or so. 

[Rvarookie]

32 minutes ago, cbmclean said:

Ponds froze over and I hit 0 °F in Wilson NC, which is in the coastal plain.  That is amazing for here.  Back then I had even less knowledge of global weather patterns than I do now, so I wasn't really paying attention to what was driving the cold.  Now I want to understand.

Always hit Wilson for Parker’s back in day

[cbmclean]

5 minutes ago, Rvarookie said:

Always hit Wilson for Parker’s back in day

I haven't been since last year right before COVID hit, but to my knowledge they are still going strong.  They did get in trouble due to some COVID compliance issues back in the fall.

https://www.witn.com/2020/09/29/coronavirus-guideline-violations-reported-at-parkers-in-wilson/

[cbmclean]

27 minutes ago, psuhoffman said:

 

 

If I recall the genesis of that arctic outbreak was mid December when a crazy epo ridge that even pinched off into a block near AK for a time went up. It dumped a ton of cold into Canada. Initially western Canada as would be expected with a epo ridge. Then late December a pna ridge went up temporarily and pressed the cold into the northeast.  By January the pattern was a convoluted mess as the pacific shifted but the cold was left to linger over the east another 10 days or so. 

We got a few inches of snow down here towards the end of the pattern which is enough to satisfy us for the most part.  The fresh snow cover was what allowed me to hit 0 °F.

Then the pattern shifted and we torched for the rest of the January and all of February.  March was chill though as you guys surly remember.

[psuhoffman]

@WxUSAF @frd @cbmclean 

That period gets brought up a lot and I get it since it was our last cold outbreak but IMO that was not an example of a pattern progression we want to rely on to get snow. First of all it took a progression of steps that aren’t likely to repeat very often. Second even though it got cold it wasn’t snowy, I know @CAPE disagrees lol, and that wasn’t a fluke.  
 

When you get a full latitude ridge like that in the eastern pacific it’s usually with a positive NAO. And the trough you get in the east is likely too progressive to lead to a big snowstorm.  I know the coast got those big coastal scrapers both years (2017 had a more brief but similar early Jan pattern) but while they were intense systems both were driven at the surface by the extreme temperate contrast created by that cold air near the warm Gulf Stream. They weren’t a response to an amplified longwave pattern. So imo both those storms were never a threat to the 95 corridor in our area. We are too far west.  The result was exactly what I would expect 90% of the time from those patterns. Cold/dry with a better chance for a progressive wave amplifying along the baroclinic zone off the coast clipping to our east.   That is not a good snow pattern for most of us in this forum. I would feel different if I lived in Cape May. 
 

Here is the double bind we’re in with the warmer pac base state. And this comment is pertaining to our longer term chances of snow not specific to now. My pattern progression thoughts have not changed.  Our most reliable snow looks are not really super cold ones. Most of the patterns that create cross polar flow and arctic outbreaks here aren’t really that good for snow.  But most of our regular old warning level snows historically came from some form of blocking (NAO/AO/Hudson bay) that forced an amplified SW under us and the temperatures were just barely cold enough.  Most of those warning events I studied temps were near 32 during the snow. A 20 degree cold powder snowstorm was never common here. We aren’t in the upper Midwest. Our common path to snow was a storm forming along the coastal baroclinic zone and with evaporation and dynamic cooling it was just cold enough.  Once in a blue moon we would get the 20 things necessary to all coincide and get some 18 degree cold smoke snowstorm.
 

There are still some rare perfect patterns that would likely work now. One would be to get a pna ridge -NAO pattern that sets in later in winter after a colder profile established in Canada. A rare epo NAO ridge bridge can also work (and will this week if the euro is right) but would be even better if the block was centered slightly northeast of where it’s projected now to prevent the mid latitude ridge from linking up. But think about how specific we’re getting now. When we start needing 12 things to be exactly this that and the other...well 2 years without any snow is what you get.  And if you eliminate all the snow we got historically with marginal air masses snow would be VERY rare here.  
 

The pac jet does look to retract some next week. Not to historically good levels but to not the raging firehose of hell it’s been.  That combined with blocking in Canada and being the core of winter should give us some legit good looks. But longer term we need to say a prayer to whatever gods you worship that the pac jet and warm pac base state isn’t permanent. Yes I know overall it’s warming and there is no denying that but maybe the current spike is a peak in the longer term ups and downs, because no matter what pattern manipulations we do it’s hard to get snow with a  huge furnace of heat upwind of us and a raging jet blasting that air towards us. 

[cbmclean]

7 minutes ago, psuhoffman said:

That period gets brought up a lot and I get it since it was our last cold outbreak but IMO that was not an example of a pattern progression we want to rely on to get snow. First of all it took a progression of steps that aren’t likely to repeat very often. Second even though it got cold it wasn’t snowy, I know @CAPE disagrees lol, and that wasn’t a fluke.

Thanks for the analysis.  I suspected that it was likely not a reproducible pattern but in desperation I'm looking for anything which might possibly "work".

Speaking of the Pac Jet, you have mentioned that our choice is to have it either pointed at us, with the result being a Pac puke torch, or else at Canada, with the result that our source region torches.  Is there no configuration which leads to it being pointed to the southeast, like at Mexico?  You have never mentioned that as a possibility so I am assuming its not feasible, but I was wondering why.

[JakkelWx]

9 minutes ago, psuhoffman said:

Once in a blue moon we would get the 20 things necessary to all coincide and get some 18 degree cold smoke snowstorm.

Yes. Feb 1979 to name one. I can't really think of another snowstorm recently that gave us 1-2 feet or more with temps in the teens. Next probably won't be for another 20 years

[Interstate]

9 minutes ago, JakkelWx said:

Yes. Feb 1979 to name one. I can't really think of another snowstorm recently that gave us 1-2 feet or more with temps in the teens. Next probably won't be for another 20 years

Dec 09 and Feb 03 I believe. 

[CAPE]

1 minute ago, cbmclean said:

Thanks for the analysis.  I suspected that it was likely not a reproducible pattern but in desperation I'm looking for anything which might possibly "work".

Speaking of the Pac Jet, you have mentioned that our choice is to have it either pointed at us, with the result being a Pac puke torch, or else at Canada, with the result that our source region torches.  Is there no configuration which leads to it being pointed to the southeast, like at Mexico?  You have never mentioned that as a possibility so I am assuming its not feasible, but I was wondering why.

I would have to look at the composites but I believe it was a similar Pac pattern in Jan of 2017 that produced a coastal plain snowstorm at almost the same time in Jan. Wasn't as cold a period as 2018, but the result was very similar with a major snowstorm right along the coast. I chased both those storms in Rehoboth Beach DE. 

[psuhoffman]

1 minute ago, cbmclean said:

Thanks for the analysis.  I suspected that it was likely not a reproducible pattern but in desperation I'm looking for anything which might possibly "work".

Speaking of the Pac Jet, you have mentioned that our choice is to have it either pointed at us, with the result being a Pac puke torch, or else at Canada, with the result that our source region torches.  Is there no configuration which leads to it being pointed to the southeast, like at Mexico?  You have never mentioned that as a possibility so I am assuming its not feasible, but I was wondering why.

We’re talking about the mid latitude jet not the sub tropical stream. It can still snow here. Don’t take this as a “it will never snow again” post. But we also can’t deny it’s getting harder. The frequency of single digit and <5” DC winters is going up consistently.  The length between snowy periods keeps increasing.   I can play around with the longwave pattern in my mind to dream to ways to snow despite the pac but when I start to have to get that specific and stack factors it becomes less and less likely. Historically “just get a block and force a SW under us” was the path. Now we need that plus 3 other things.  Another issue is ridges have more amplitude now.  Warmth gets further north. So an epo ridge western trough that might have has a suppressed eastern ridge in some analog 40 years ago...I don’t know if that would even work anymore. I suppose the perfect pattern would be a ridge a little east of where the epo one is this week and a NAO block. So the trough is over the central US but not far enough west to capture tropical pacific and gulf heat and pump the ridge east of it. The southeast ridge would be suppressed by the NAO and the Atlantic can’t add the same heat because it’s down wind. That would work. But that’s so specific it’s just not going to happen that often. 

[psuhoffman]

13 minutes ago, JakkelWx said:

Yes. Feb 1979 to name one. I can't really think of another snowstorm recently that gave us 1-2 feet or more with temps in the teens. Next probably won't be for another 20 years

I don’t know that 79 fits this but also some storms that were like 20 degrees it still wasn’t really a true arctic airmass from cross polar flow. It was from a domestic cold source but the airmass was very dry and when it saturated we got a very cold storm. But with the pac jet blasting maritime air in we don’t get those “dry” air-masses domestically anymore.  Crows polar flow was always super rare. We have to be able to generate enough cold from air that didn’t have to come from Siberia or were in trouble.  

[benjammin]

Yes. Feb 1979 to name one. I can't really think of another snowstorm recently that gave us 1-2 feet or more with temps in the teens. Next probably won't be for another 20 years

In February 1979 there was snow on the ground before it started. What a great, intense storm.

Sent from my motorola edge plus using Tapatalk

[psuhoffman]

9 minutes ago, CAPE said:

I would have to look at the composites but I believe it was a similar Pac pattern in Jan of 2017 that produced a coastal plain snowstorm at almost the same time in Jan. Wasn't as cold a period as 2018, but the result was very similar with a major snowstorm right along the coast. I chased both those storms in Rehoboth Beach DE. 

It was but neither of those storms was ever a legit high probability threat to DC. They weren’t the result of an amplified longwave pattern they were spawned by the temperate contrast off the coast due to the cold over a warm Gulf Stream. They were always destined to be coastal scrapers. 

[psuhoffman]

Btw don’t know if this is a coincidence but 79 has been a pattern analog recently 

ETA: just checked today’s update and low and behold Jan 28 1979 is the number 1 CPC pattern analog 

[psuhoffman]

Last thought on the long term climate/pattern thing. Those cpc analogs kind of support my claims. If you were checking the pattern analogs all cold season at no point have they been spitting out shutout analogs. And in some cases they were spitting out very cold/snowy periods. But even at their worst they were mostly periods with some snow. And those take into account the pacific same as everything else. There is ample evidence patterns that worked in the past are not now.  The next 2 weeks is a major test. This coming look a -epo with a retrograding block historically leads to cold/snow almost every time. Not necessarily 20” but we should not get blanked from that. 

[osfan24]

I don't remember December 2009 being that cold, but the second February 2010 storm was quite cold. I also remember 1996 and 2003 being quite cold at times. 1996 it was in the mid teens and snowing. 2003 the temperature fluctuated, but I remember it being in the high teens and sleeting in College Park toward the end of the storm. Don't think 2016 got that cold until the deform.

[Cobalt]

Compared to 18z yesterday, the GFS is showing more frozen precip when the primary lp is up in Minnesota, rather than showing mostly rain when the low pressure was in southern Virginia during that 18z Saturday run.