Re: Long Range Thread 29.0

[amugs]

The EPO WPO couplet is going to drill the cold air in and the +TNH pattern is going to last through early February, may be longer. I do not see cutters in this upcoming pattern, 2014 type pattern incoming. We had a +NAO and AO with a Scan Block and the EPO/WPO couplet did the dirty work for us.

+EAMT is prevalent which is going to force the jet extension equatorial and a trough N of Hawaii which will pump the EPO N. The gradient will be pressed S and E of our area.

[frank 638]

The EPO WPO couplet is going to drill the cold air in and the +TNH pattern is going to last through early February, may be longer. I do not see cutters in this upcoming pattern, 2014 type pattern incoming. We had a +NAO and AO with a Scan Block and the EPO/WPO couplet did the dirty work for us.

+EAMT is prevalent which is going to force the jet extension equatorial and a trough N of Hawaii which will pump the EPO N. The gradient will be pressed S and E of our area.

when do you think this block will finally move .because this block is so strong.everytime we try to get a snowstorm it slides to our south

[Irish]

Any more thoughts on the 19th-20th system?

[Frank_Wx]

I might be a bit more on the pessimistic side when it comes to the 20th storm signal. A few pages back, I posted the MJO and ENSO trends. They show a deepening La Niña and a moderate MJO wave moving from phase 1 to 2.

The 500mb map of an MJO in phase 2 in a La Niña background state:



I saw Ray already commented that the western ridge is a little too far west, and Scott posted the teleconnections which showed the EPO going negative. That pretty much matches the map above. But what you also see, and is also shown on the latest Ensembles, is the Atlantic ridge is too far west now. The -NAO is either weak or breaking down completely. In my opinion, this has the look of “cutter” pattern. Maybe this will be just a transient 7 day period before the pattern shifts again. Or maybe the MJO wave dies. Or maybe the NAO sticks around to setup a Miller B. Let’s see where things stand in a few days.

What will be dreadful are the next 7-9 days of cold and dry. Wasted cold. Not fun.

[heehaw453]

Any more thoughts on the 19th-20th system?

ATTM it favors the interior for snow, but I95 not a dead threat. Mixing and rain is more of a possibility towards the coastal plane.

The more the PNA ridge pushes east the better as shown on the picture. That will push the trough axis and WAR east too making it much more likely coastal plane is frozen precip. Again the 50/50 has hauled on out so no suppression concerns, but now thermals are trickier. It's all about where the boundary layer sets up. These setups are nice for those on the right side of the boundary and BIG disappointment for those that are not. I would say a few more days of trends on the ensembles will provide decent insight. No phasing here so less complex.

[amugs]

Any more thoughts on the 19th-20th system?

ATTM it favors the interior for snow, but I95 not a dead threat. Mixing and rain is more of a possibility towards the coastal plane.

The more the PNA ridge pushes east the better as shown on the picture. That will push the trough axis and WAR east too making it much more likely coastal plane is frozen precip. Again the 50/50 has hauled on out so no suppression concerns, but now thermals are trickier. It's all about where the boundary layer sets up. These setups are nice for those on the right side of the boundary and BIG disappointment for those that are not. I would say a few more days of trends on the ensembles will provide decent insight. No phasing here so less complex.

I agree Haw the boundary location is crucial and like I said last night I like where we are with this.
That N EPO as I stated last night is a beast and the press will not be felt until we get closer. The TPV lobe along with this N EPO will help build confluence over the top preventing this from cutting. LLC at this time of year ENS cannot see undercutting the pattern as deterministic models really can not either. Lastly we have one hell of a snowpack to our NW in CAN to help and Hudson Bay is mostly frozen:




So, a mix along the coast is possible as you state so is a snowstorm. IF things change over the next 10 days, why not they always do, either favorably which I feel they will due the EPO and WPO couplet, or unfavorably if the EPO is not as strong and we get the WAR stronger and more towards the coast then things change and the gnashing of teeth and frustrations start to rear their ugly heads.
We shall see of course.

[sroc4]

Any more thoughts on the 19th-20th system?

ATTM it favors the interior for snow, but I95 not a dead threat. Mixing and rain is more of a possibility towards the coastal plane.

The more the PNA ridge pushes east the better as shown on the picture. That will push the trough axis and WAR east too making it much more likely coastal plane is frozen precip. Again the 50/50 has hauled on out so no suppression concerns, but now thermals are trickier. It's all about where the boundary layer sets up. These setups are nice for those on the right side of the boundary and BIG disappointment for those that are not. I would say a few more days of trends on the ensembles will provide decent insight. No phasing here so less complex.

I agree Haw the boundary location is crucial and like I said last night I like where we are with this.
That N EPO as I stated last night is a beast and the press will not be felt until we get closer. The TPV lobe along with this N EPO will help build confluence over the top preventing this from cutting. LLC at this time of year ENS cannot see undercutting the pattern as deterministic models really can not either. Lastly we have one hell of a snowpack to our NW in CAN to help and Hudson Bay is mostly frozen:




So, a mix along the coast is possible as you state so is a snowstorm. IF things change over the next 10 days, why not they always do, either favorably which I feel they will due the EPO and WPO couplet, or unfavorably if the EPO is not as strong and we get the WAR stronger and more towards the coast then things change and the gnashing of teeth and frustrations start to rear their ugly heads.
We shall see of course.

One thing we have to keep in mind with these systems is what is almost always underestimated in the LT and Md term is the strength of the southern systems, either out of the STJ or the Pac Jet.  With that because we lose our -AO and -NAO it wont take much to amplify the WAR.  With a juiced southern system, which you can count on given the temp gradients going to be in place from N to S as it traverses the Sothern Plains, you can count on latent heat release out ahead to add some oomf to the  SE Ridge.  Without the AO/NAO couplet, and the PNA ridge axis where it is currently forecast to be, It wouldn't surprise me at all to see the cutter soln win the day here unless the -EPO can push the cold air far enough south well ahead of our system. Even then there are hurdles, esp the coast.

Also quick note on the idea that why is it the cutters in the LR always come to fruition; whereas the major EC snowstorm for the NYC metro always seem to fail.  Remember a cutter has a window to success that is like 750-1000miles wide; whereas for our little coverage area we have to have the storm track follow an extremely narrow window.  The difference to success is like throwing a baseball through wide open French doors vs throwing a baseball through a little doggy door from 110feet away.  Its doable either way but the odds are def more favorable.  

[rb924119]

For what it’s worth, I don’t fundamentally disagree with anything that’s been said by Scott (sroc), heehaw, Frank, and mugsy regarding our upcoming threat window of the 18th-22nd. At face value, it does look like we are set up in a way that puts us at risk of a cutting storm. That said, I think the thorn in our side of holding the tails back in the Southwest helps our cause in this case. In addition to the -EPO/-WPO couplet, the current alignment of the ridge axis off the West Coast continues to support the idea that troughing will try to carve itself out back there. But in so doing, this should (in theory) allow for any incoming troughs to remain positively tilted as they propagate eastward. As a result, and just like with our system today/tomorrow, this should help to mitigate height rises along the Eastern Seaboard. Northern stream energy should be able to get out ahead of energy trapped/hanging back in the Southwest, dampen the flow, and then allow the trailing energy to either shear out (like our current storm), or follow it up with fresh cold air. I haven’t taken a close look at where I think that battleground might be, but I think the sentiments already expressed sound pretty good.

[rb924119]

Addendum to my above: Scott, EXCELLENT explanation of why cutters always verify!

[sroc4]

For what it’s worth, I don’t fundamentally disagree with anything that’s been said by Scott (sroc), heehaw, Frank, and mugsy regarding our upcoming threat window of the 18th-22nd. At face value, it does look like we are set up in a way that puts us at risk of a cutting storm. That said, I think the thorn in our side of holding the tails back in the Southwest helps our cause in this case. In addition to the -EPO/-WPO couplet, the current alignment of the ridge axis off the West Coast continues to support the idea that troughing will try to carve itself out back there. But in so doing, this should (in theory) allow for any incoming troughs to remain positively tilted as they propagate eastward. As a result, and just like with our system today/tomorrow, this should help to mitigate height rises along the Eastern Seaboard. Northern stream energy should be able to get out ahead of energy trapped/hanging back in the Southwest, dampen the flow, and then allow the trailing energy to either shear out (like our current storm), or follow it up with fresh cold air. I haven’t taken a close look at where I think that battleground might be, but I think the sentiments already expressed sound pretty good.

Dont forget I dont think the reasons why this upcoming system is suppressed will apply to the next time frame.  There is a resistance in the N and E associated with the neg AO and NAO couplet, combined with our poorly timed wave break in the NW.  We lose the resistance in the N&E for the 18-20th.  Again if there is any oomf to the system coming out of the SW there wont be much to prevent the height rises out ahead.  Unless of course like you said a n/s s/w can create some sort of confluence in front of it.  This as per usual boils town to timing, the likes of which wont be recognized for quite some time.

[hyde345]

You know what would really suck? If we had 2 weeks of cold and little precip, then it rained, and then it got very cold again. That would be a real kick in the ass. It's still over a week out but the possibility of an inland runner or cutter in the 19th-22nd time frame is very real.

[rb924119]

For what it’s worth, I don’t fundamentally disagree with anything that’s been said by Scott (sroc), heehaw, Frank, and mugsy regarding our upcoming threat window of the 18th-22nd. At face value, it does look like we are set up in a way that puts us at risk of a cutting storm. That said, I think the thorn in our side of holding the tails back in the Southwest helps our cause in this case. In addition to the -EPO/-WPO couplet, the current alignment of the ridge axis off the West Coast continues to support the idea that troughing will try to carve itself out back there. But in so doing, this should (in theory) allow for any incoming troughs to remain positively tilted as they propagate eastward. As a result, and just like with our system today/tomorrow, this should help to mitigate height rises along the Eastern Seaboard. Northern stream energy should be able to get out ahead of energy trapped/hanging back in the Southwest, dampen the flow, and then allow the trailing energy to either shear out (like our current storm), or follow it up with fresh cold air. I haven’t taken a close look at where I think that battleground might be, but I think the sentiments already expressed sound pretty good.

Dont forget I dont think the reasons why this upcoming system is suppressed will apply to the next time frame.  There is a resistance in the N and E associated with the neg AO and NAO couplet, combined with our poorly timed wave break in the NW.  We lose the resistance in the N&E for the 18-20th.  Again if there is any oomf to the system coming out of the SW there wont be much to prevent the height rises out ahead.  Unless of course like you said a n/s s/w can create some sort of confluence in front of it.  This as per usual boils town to timing, the likes of which wont be recognized for quite some time.

No, yeah - same page, brother I’m just speculating that if history is any indication, the timing of northern stream versus southwestern energy should work to our benefit, with all other components in consideration.

[rb924119]

I may be able to offer a better discussion/demonstration tonight, but I don’t know what my schedule is going to look like over the next few days because I’m visiting my best friend and his family, so everything is pretty spontaneous haha

[amugs]

EPO SD of 3 is  going to send a cold arctic air mass and set up the boundary. The WAR is a bit of a good thing for this boundary to help not allow the storms to escape OTS.



WPO



This will set the boundary up - hopefully as it did similar to 2014 S and E. Teles are quite similar to that time frame.

[heehaw453]

EPO SD of 3 is  going to send a cold arctic air mass and set up the boundary. The WAR is a bit of a good thing for this boundary to help not allow the storms to escape OTS.



WPO



This will set the boundary up - hopefully as it did similar to 2014 S and E. Teles are quite similar to that time frame.

100% true Mugs. The WAR is necessary otherwise without a strong STJ storms would roll out to sea. It just has to setup in the right place and there will be adjustments to it as waves roll through. So I think even if 1/19-1/20 fails other waves will roll through thereafter. We might be in an for an SWFE pattern best I can tell.

Also around the 13th/14th I won't surprised to see a clipper type system pop up out of no where. The PNA pumps and the AO flips to positive. These inflections sometimes can be interesting.

[rb924119]

EPO SD of 3 is  going to send a cold arctic air mass and set up the boundary. The WAR is a bit of a good thing for this boundary to help not allow the storms to escape OTS.



WPO



This will set the boundary up - hopefully as it did similar to 2014 S and E. Teles are quite similar to that time frame.

100% true Mugs. The WAR is necessary otherwise without a strong STJ storms would roll out to sea. It just has to setup in the right place and there will be adjustments to it as waves roll through. So I think even if 1/19-1/20 fails other waves will roll through thereafter. We might be in an for an SWFE pattern best I can tell.

Also around the 13th/14th I won't surprised to see a clipper type system pop up out of no where. The PNA pumps and the AO flips to positive. These inflections sometimes can be interesting.

I think you make a very salient point in this post. I think there may be a thought that this is going to be a singular system that rolls through, which we are afraid of cutting. While that’s possible, I think there may be a more likely situation where we have an initial wave that DOES cut to some degree or other, and brings some kind of wintry precip (snow/slop to be determined), but then it’s the wave that may come in BEHIND this right on its heels that rounds the bend and gives us a shot something more significant. Almost like a dumbed down version of February 2014. A lot of people remember the blizzard on the 23rd-25th, but very few remember the weak wave that rode the frontal boundary 36 hours before that dropped up to a foot of snow in the terrain to the north and west of I-95, while the coastal plain had a cold rain. This is an idea that I’m toying with, though haven’t looked closely at yet.

[rb924119]

I remember that well for three reasons:

1. Because it was one of the only times that I ever got a five-day weekend because of snow days in grade school lol

2. Because it was one of the few times I’ve seen a snow pack that deep.

3. Because I wrote a paper on this on college.

[heehaw453]

EPO SD of 3 is  going to send a cold arctic air mass and set up the boundary. The WAR is a bit of a good thing for this boundary to help not allow the storms to escape OTS.



WPO



This will set the boundary up - hopefully as it did similar to 2014 S and E. Teles are quite similar to that time frame.

100% true Mugs. The WAR is necessary otherwise without a strong STJ storms would roll out to sea. It just has to setup in the right place and there will be adjustments to it as waves roll through. So I think even if 1/19-1/20 fails other waves will roll through thereafter. We might be in an for an SWFE pattern best I can tell.

Also around the 13th/14th I won't surprised to see a clipper type system pop up out of no where. The PNA pumps and the AO flips to positive. These inflections sometimes can be interesting.

I think you make a very salient point in this post. I think there may be a thought that this is going to be a singular system that rolls through, which we are afraid of cutting. While that’s possible, I think there may be a more likely situation where we have an initial wave that DOES cut to some degree or other, and brings some kind of wintry precip (snow/slop to be determined), but then it’s the wave that may come in BEHIND this right on its heels that rounds the bend and gives us a shot something more significant. Almost like a dumbed down version of February 2014. A lot of people remember the blizzard on the 23rd-25th, but very few remember the weak wave that rode the frontal boundary 36 hours before that dropped up to a foot of snow in the terrain to the north and west of I-95, while the coastal plain had a cold rain. This is an idea that I’m toying with, though haven’t looked closely at yet.

Yep. Kinda like today's 12Z GEM. The first wave cuts set the boundary to our south and then another one forms on the boundary. I see that way more likely than the first wave being just right.

[heehaw453]

This is the point where I get interested. Right when the WAR is kissing the coast. That's when a boundary sets up between EPO driven cold and the warmer WAR. You can squeeze a wave on that boundary. Honestly I would love for the WAR to keep flexing in and around that area.

[amugs]

The - PNA is going to send systems to our region hence CPC outlook of AN precipitation the last 1/2 of January.  Now I am using 2014 as my go to example because of the reasons stated previously the EPO, WPO, WAR set up and throw in the TPV lobe over SE Region of Canada. Many wx folks back then had no idea how exciting and eventful this period would be with storms galore. I am not saying storms galore but it’s a hell of lot better than what we have experienced. The chances are going to be there and some may pop up out of nowhere when the arctic boundary sets up then its game on. These like to get entrenched and if we can get the STJ/GOM to partake in this some maybe pleasantly surprised.

This is basically the 20th -24th time frame of precip for our area.

[amugs]

Day 15 American/European ensemble clusters show either Alaska ridge (for cold U.S.) or strong Alaska ridge (for very cold U.S.). pic.twitter.com/Z8c33QpqVb

— Commodity Wx Group (@commoditywx) January 10, 2025

The top right has the EURO saying so.....whoaa!!!!
Bottom right is the result ala FEB 2014!!

[heehaw453]

Op Model GFS way out there so this not to say what will occur. But this kind of h5 sets boundary nicely. You want that western ridge getting into ID and the WAR just tickling the coast. Now you set the boundary up and waves ride it. Those setups can produce BIG Time and they're way easier than the phasing scenarios provided you are on the cold side of the boundary. The air mass clash does all the work.

Jan 19-23 is a window of high interest for me.

[Irish]

Something brewing for the 19th-22nd...

[heehaw453]

18Z GEFS

[SENJsnowman]

Pardon me heehaw, but that 540 line is so far North and West. So what am I missing in these pics? Is that not the boundary you are referring to? Is it expected to drop to the South and East as a shortwave rides along the frontal boundary? Or is the 'boundary' actually the eastern edge of the blue blob? And is that white zone in between blue and yellow a projected storm track as per this particular ensemble mean?

If you would be so kind...

[heehaw453]

Pardon me heehaw, but that 540 line is so far North and West. So what am I missing in these pics? Is that not the boundary you are referring to? Is it expected to drop to the South and East as a shortwave rides along the frontal boundary? Or is the 'boundary' actually the eastern edge of the blue blob? And is that white zone in between blue and yellow a projected storm track as per this particular ensemble mean?

If you would be so kind...

That's not critical thickness it's heights. You normally look at thickness for rain/snow line. The thickness is the vertical distance between two pressure differences. Heights are more associated with vorticity advection (where the s/w's are moving too). Some of the other mets can explain that better than I can. So when you see 540 on heights that is not really rain/snow line, but for thickness Yes it normally is a loose indicator or rain/snow line. This GEFS representation is plenty cold for snow...

We just have to see where our boundary winds up. Suppression most likely is not going to be the issue if we fail. Just focus on where the WAR sets up and the western ridge. The trough axis will move according to the PNA ridge.

[SENJsnowman]

Your explanation was plenty sufficient...thank you!!