December Mid/Long Range Discussion

[paulythegun]

The latest euro weeklies suggest that January will either look like the euro weeklies or that their 0.001% added value will not prove useful beyond random dart throwing and climo

[pazzo83]

5 hours ago, Deck Pic said:

The 2/4/95 event was a pretty nice one for I-95.  K/U event.  I think the pattern was garbage and we thread the needle.  But yeah, at least around here the winter mostly sucked outside of that.  I think 72-73 is a better overall analog than 94-95 in terms of bad winters.. of course that winter was a total debacle.  I'm not concerned yet.  December isnt a winter month.

just refreshing my memory (I remember a good amount of snow in the Shenandoah Valley - we were trying to drive to Massanutten to go skiing): http://www.raymondcmartinjr.com/weather/1995/04-Feb-95.html

[pazzo83]

4 hours ago, Deck Pic said:

95-96 would go on my personal list of banned terms in this forum along with January 25, 2000 and many others.

 

March 2001 - from the other side of the coin.

[nj2va]

GFS with quite the rain maker starting Sunday.  Basically occludes and stalls over the Mid Atlantic.  2-4”+ area wide.

Gotta think with this active STJ, we’ll score with a significant snowstorm once we get some help from the pac and atl.

[Weather Will]

WB 0Z GEFS, colder at the end of its run compared to 18Z and compared to average...maybe today will be a better day!!!

[Ralph Wiggum]

5 hours ago, pazzo83 said:

March 2001 - from the other side of the coin.

Boxing Day?

[Weather Will]

WB 0Z EPS Day 14 compared to yesterday.  Looks better!

[CAPE]

Mean suggests some frozen for this window. Biggest difference on the 0z run is some improvement in the NA. The op run has been hinting at heights increasing in the NAO domain via wave breaking. Something to keep an eye on over the next several runs, and need to see it on the EPS.

[Weather Will]

WB 6Z GFS.....early next week system....20 degrees colder this run....buckle up!!!!

[Ji]

Gfs tries to give us winter weather next week as part of that noreaster

Sent from my SM-A515U using Tapatalk

[Wxdavis5784]

35 minutes ago, Weather Will said:

WB 6Z GFS.....early next week system....20 degrees colder this run....buckle up!!!!

It won’t happen because Snowman19 is confused. 

[Benjamn3]

In the words of Geralt of Rivia “hmmmm”. 

[Lowershoresadness]

36 minutes ago, Benjamn3 said:

In the words of Geralt of Rivia “hmmmm”. 

you spelled Geraldo Rivera wrong

[MDScienceTeacher]

59 minutes ago, Wxdavis5784 said:

It won’t happen because Snowman19 is confused. 

LOL.. 2 meter temp change run to run.  They know who their users are.

[Terpeast]

Good, now lets see if EPS follows, and both hold onto this colder look for 2 more cycles

[CAPE]

10 minutes ago, Terpeast said:

Good, now lets see if EPS follows, and both hold onto this colder look for 2 more cycles

6z GEFS didn't really follow up with the colder look. Barely a hint of a coastal low for that period and NA looks more like previous runs. More watching.

[brooklynwx99]

7 minutes ago, CAPE said:

6z GEFS didn't really follow up with the colder look. Barely a hint of a coastal low for that period and NA looks more like previous runs. More watching.

OP runs have been keying in on a wave break into central Canada. this would be a much more interesting look if it retrogrades into NW Canada or Greenland like it has over the last few runs

[mattie g]

14 hours ago, Terpeast said:

CFS shows a literal nina for next year

If this year is 94-95, then maybe next year is 95-96.

[olafminesaw]

Good to see the PNA trend more positive. Would at least get some cold air to this side of the continent 

[stormy]

Yesterday afternoon both Ji and I expressed suspicion of possible surprises early next week with an east coast storm.  This Watch still exists this morning.

The GFS,GEM and Euro all see a significant system affecting the SE/MA coastal region during this Sunday - Wednesday timeframe.

Heavy rain, snow and wind are all in the mix with run to run hiccups. The op GFS even gives my area 2 inches of snow on Tuesday night but the GEFS keeps any snow in the mts. to my northwest.

The latest ECM gives more impact to the area east of I-95 while the GFS suspects more inland impact.

 

[psuhoffman]

53 minutes ago, brooklynwx99 said:

OP runs have been keying in on a wave break into central Canada. this would be a much more interesting look if it retrogrades into NW Canada or Greenland like it has over the last few runs

I'm becoming increasingly confident this is entirely about the NAO.  First of all if you look at all the best analogs identified, 1958, 1966, 1973, 1987, 1992, 1995, 2010, 2016 the thing that differentiates them wrt snowfall was the NAO in those seasons.  58, 66, 87, 2010 were negative and snowy in the mid atlantic.  73, 92, 95 were positive and not.  2016 was the most ambiguous with some blocking in Jan/Feb but not as pronounced as the others and it ended up in between.  

 

Also look at days 4-8 on the EPS. 

The problem isn't the Pacific.  At range things get washed out and give the wrong impression.  Because pieces of the main vortex keep getting pulled off and diving into the CONUS, at range timing differences make that look like the vortex is actually extending into the west more than it is.  But look as it gets closer what it actually looks like.  

That low off the west coast is cut off, that's not a problem...the main Pac vortex is centered west of AK.  There is ridging into western Canada.  The issue there is the TPV over Baffin or IOW a raging positive NAO.  Because of that the PNA ridging just spreads out east across the CONUS.  If the NAO was negative that pacific look right there, day 4-8 not way out in time, would work just fine.  

This seems really simple to me...if we get the NAO to flip negative we will be fine, it will promote enough northerly flow into the northeast on top of us for these STJ systems to work...but if the NAO stays positive were screwed, the ridging out west off the PAC will just spread east and we end up with a full continent pacific onslaught. 

In a nino it really is all about the NAO.  There have really only been 2 exceptions in modern history...2003 and 1998.  1998 was so east based and so extreme due to the contrast between the super nino and a colder pac base state that it torched the CONUS despite a -NAO.  And 2003 was opposite, the Pacific trough was displaced west by the extreme modoki nature of that nino and so it worked out despite a less favorable NAO, although it wasnt as bad as what we have right now, not sure anything would save us with a strong vortex over Baffin, thats just nightmare stuff right there.  

 

[brooklynwx99]

3 minutes ago, psuhoffman said:

I'm becoming increasingly confident this is entirely about the NAO.  First of all if you look at all the best analogs identified, 1958, 1966, 1973, 1987, 1992, 1995, 2010, 2016 the thing that differentiates them wrt snowfall was the NAO in those seasons.  58, 66, 87, 2010 were negative and snowy in the mid atlantic.  73, 92, 95 were positive and not.  2016 was the most ambiguous with some blocking in Jan/Feb but not as pronounced as the others and it ended up in between.  

 

Also look at days 4-8 on the EPS. 

The problem isn't the Pacific.  At range things get washed out and give the wrong impression.  Because pieces of the main vortex keep getting pulled off and diving into the CONUS, at range timing differences make that look like the vortex is actually extending into the west more than it is.  But look as it gets closer what it actually looks like.  

That low off the west coast is cut off, that's not a problem...the main Pac vortex is centered west of AK.  There is ridging into western Canada.  The issue there is the TPV over Baffin or IOW a raging positive NAO.  Because of that the PNA ridging just spreads out east across the CONUS.  If the NAO was negative that pacific look right there, day 4-8 not way out in time, would work just fine.  

This seems really simple to me...if we get the NAO to flip negative we will be fine, it will promote enough northerly flow into the northeast on top of us for these STJ systems to work...but if the NAO stays positive were screwed, the ridging out west off the PAC will just spread east and we end up with a full continent pacific onslaught. 

In a nino it really is all about the NAO.  There have really only been 2 exceptions in modern history...2003 and 1998.  1998 was so east based and so extreme due to the contrast between the super nino and a colder pac base state that it torched the CONUS despite a -NAO.  And 2003 was opposite, the Pacific trough was displaced west by the extreme modoki nature of that nino and so it worked out despite a less favorable NAO, although it wasnt as bad as what we have right now, not sure anything would save us with a strong vortex over Baffin, thats just nightmare stuff right there.  

 

luckily, I don't think we'll really have to worry about the NAO. would be different if we had a death star SPV, but it's weak, and we have already had spells of blocking this fall and earlier in the month. i highly doubt the NAO domain remains like that for too long, let alone for the rest of the winter

[psuhoffman]

3 minutes ago, brooklynwx99 said:

luckily, I don't think we'll really have to worry about the NAO. would be different if we had a death star SPV, but it's weak, and we have already had spells of blocking this fall and earlier in the month. i highly doubt the NAO domain remains like that for too long, let alone for the rest of the winter

I tend to agree, weak SPV, descending -QBO, ascending solar... we shouldn't get a raging wall to wall +NAO... but that is the domain we need to be watching for changes more so than the pacific even imo.  The biggest reason for the loss of the better pattern projected for the end of Dec and early January on guidance was the degradation of the look on the Atlantic side more so than the Pacific.  

[psuhoffman]

That and this is a basin wide nino which isn't a bad thing...provided you have some NAO help.  But were not in a modoki like 2003 and 2015 where the pacific low will be displaced far enough west to work absent any NAO help.  

[Terpeast]

This recent -NAO late november, which model sniffed it out first? Gfs or euro?

just curious

[psuhoffman]

Just now, Terpeast said:

This recent -NAO late november, which model sniffed it out first? Gfs or euro?

just curious

One may have had it 12 hours sooner but both picked up on it about the same time since it showed up quick and not at super long leads.  

[brooklynwx99]

3 minutes ago, psuhoffman said:

I tend to agree, weak SPV, descending -QBO, ascending solar... we shouldn't get a raging wall to wall +NAO... but that is the domain we need to be watching for changes more so than the pacific even imo.  The biggest reason for the loss of the better pattern projected for the end of Dec and early January on guidance was the degradation of the look on the Atlantic side more so than the Pacific.  

the only issue is that with these kinds of winters with a generally susceptible -NAO state, they can just kind of pop up in the medium to semi-long range. that's what happened with the blocking spell early in the month. nothing really sniffed it out

if we are seeing a legit anomalous, long lasting -NAO brought on by Scandi ridging, it is probably very legit and we could get smoked. but that's speculation, of course. a SSW could help that occur, though

[psuhoffman]

Given the weak SPV it's possible for the NAO to shift quickly, all it would take is a good wave break to possibly set off a chain reaction.  One thing that does bother me a little... in the years that flipped in our favor there was pronounced Scandinavian ridging ahead of time in late December that proceeded the NAO going negative.  We don't have that this year...it looks like we will be relying on wave breaking to get it done and that's not how it went down in past Nino's that had an NAO flip Dec to Jan.  

[Maestrobjwa]

1 hour ago, psuhoffman said:

Given the weak SPV it's possible for the NAO to shift quickly, all it would take is a good wave break to possibly set off a chain reaction.  One thing that does bother me a little... in the years that flipped in our favor there was pronounced Scandinavian ridging ahead of time in late December that proceeded the NAO going negative.  We don't have that this year...it looks like we will be relying on wave breaking to get it done and that's not how it went down in past Nino's that had an NAO flip Dec to Jan.  

So...if the NAO were to end up sinking the ship this winter, would you attribute that to worsening climo, just bad luck, or worsening climo making said bad luck harder to overcome?

[ldub23]

 

Another  lt snow  event  possible?