Central PA - Winter 2020/2021

[Blizzard of 93]

4 hours ago, MAG5035 said:

Might not want to sleep on this New Year's event potentially becoming some kind of a wintry mix event in C-PA.  Models have been toying around with sending the first piece up into the lakes, pulling a front across and holding back a good bit of energy for another wave to roll up. While the southern wave builds, models have been getting some high pressure in place over us/just to our north. Positioning of the mid-level features (850 & 700 lows well west) definitely aren't looking ideal for an extended snow event, but get that high over us for at least a bit and we probably are going to be dealing with some kind of messy mix event on at least the front end. 

The 0z GFS & Canadian agree with the concern of a messy mix event possibility this coming weekend. The Euro also has it, but to a lesser extent. It will depend on the strength of the High to determine how much mixing CTP would get and the duration before changing to rain.

 

[Blizzard of 93]

We also need to keep an eye on the chance of a follow up storm chance next Sunday or Monday. Some models have shown the chance over the last few days, but most have not been developing a storm or have been keeping any storm chance well offshore.

The 0z Canadian shows this potential storm chance and the Para-GFS apparently also shows it according to some posters in other regional threads on here.

So while we wait for the good -NAO blocking pattern to get into a better position over the next couple of weeks, we might have a wintry event or two to track in the meantime.

[Blizzard of 93]

17 hours ago, Blizzard of 93 said:

It’s just a matter of time until the blocking pays off for our Winter Storm chances,

One the -NAO blocking shifts a little to the west, we should be in business. 

We just need to stay patient.

This is a beautiful west based -NAO blocking pattern on the 0z EPS & GEFS. The blocking has been consistently shifting to the west over the last several ensemble runs, but it will take a little time to get there. 
The week of the 10th of January onward could be loaded with winter storm chances for us if this pattern arrives as advertised.

 

 

 

[paweather]

10 hours ago, Blizzard of 93 said:

The 0z GFS & Canadian agree with the concern of a messy mix event possibility this coming weekend. The Euro also has it, but to a lesser extent. It will depend on the strength of the High to determine how much mixing CTP would get and the duration before changing to rain.

 

Thanks Bliz and Mag I was really hoping there would have been something to track over the holidays. 

[Blizzard of 93]

The end of the 12z EPS, GEFS & Canadian ensembles today all had a similar look with a great blocking pattern with a more west based -NAO and the trough in the east.

Good winter storm tracking days are ahead if this look verifies!

 

[MAG5035]

4 hours ago, Blizzard of 93 said:

The end of the 12z EPS, GEFS & Canadian ensembles today all had a similar look with a great blocking pattern with a more west based -NAO and the trough in the east.

Good winter storm tracking days are ahead if this look verifies!

 

With the EPO/WPO forecast to go way positive during at least the opening week of January, I don't think we're going to live up to this high latitude blocking pattern's potential initially. An active Pac jet (+EPO/WPO) is going to ensure trouble in getting access to any decent cold into our part of the CONUS in a pattern that had already been kind of lacking it since our big snow event with the exception of the couple days in the aftermath of the X-mas eve system. If we break this down, or better yet get a -EPO ridge to build.. then you force a better alignment from a colder source region (such as NW Canada). That coupled with the high latitude blocking in the NAO/AO realm.. ideally shifting westward a bit in time would provide a much colder pattern and a suppressed storm track that is less apt to try to cut in the east. We're just not fully there yet. 

Personally, I'm eyeing up the second half of Jan more than the first half and considering anything we do score in the next two weeks a bit of a bonus. We have a pretty decent strat-warm event seemingly in the cards in the first part of January and it usually takes a couple weeks to start realizing whatever the results are in terms of cold air outbreaks in the mid latitudes. The -NAO/AO regime is looking like more of an overall theme rather than just a passing fad and pretty much couldn't get a more opposite look from what was just getting warmed up this time last winter up in that realm. This significant of a NAO/AO blocking regime was not something I was expecting to see out of this winter. Barring a major change up there or the MJO suddenly busting out into a strong 4-5-6 pulse (currently not looking very likely attm), i'm fairly confident in saying that we're going to eventually see a really good period of winter weather set up at some point.

[Blizzard of 93]

The pattern from the end of the 15 ensembles posted above was carried forward on the Euro Weeklies run yesterday that went out to early February.

The pattern from mid to late January could bring a really good period of winter weather to our region. Once the west based block gets established, it looks to remain in place until early February according to the Euro Weeklies.

[Blizzard of 93]

The 0z Euro was on board for the follow up system on Sunday into Monday for a minor snow event for CTP.

This would be a nice little bonus while we wait for the better pattern to get established.

[Blizzard of 93]

CTP is starting to get on board with the wintry mix for New Year’s and even mentioned the possibility of the coastal for Sunday into Monday.

“With a 1035 surface high over upstate NY Thursday night, the models continue to trend colder for Friday. Cold air damming sets up with Friday morning low temps in the upper teens north to 30 degrees near the Mason-Dixon line. Held subfreezing air temps later into the day on Friday with snow now forecast. A deep low moves northeast across the Ohio valley toward the Great Lakes Friday, with a shield of overrunning / WAA precip beginning as snow and changing to a wintry mix by midday. The threat of freezing rain could lead to dangerous travel on NYE, but confidence is low at this time. In addition to winter hazards, will continue to keep an eye on flooding concerns with this storm though currently the threat has decreased. Looking at maybe 1-2 inches liquid. Colder air moves in Saturday with chance snow showers over the northwest mountains near the PA border.

Both the NAEFS and ECMWF now show a coastal storm developing next Sun-Mon, but it is too early to say if this potential storm would impact central PA.”

 

[showmethesnow]

Going by the last couple of days of runs and ignoring the latest GFS run (06Z), the late Jan 3rd into 4th time frame might be worth keeping a casual eye on if the GFS and the Euro's current model depiction and players on the field at 500s are somewhat accurate leading into that time frame. It would be a case of, 'thread the needle' as it would depend on placement and timing between these different key features to overcome an unfavorable storm track within the general overall flow through the CONUS. This, 'thread the needle' scenario actually would have somewhat better odds then what we would typically expect as there are several evolutions of these key players that would be a win for some portions of the east, most of which probably favor portions of the mid-Atlantic and possibly up the coastal areas to the north somewhat. But the usual caveats apply here as we are talking op runs somewhat at range, with NS (north stream) features that the models are notorious for mishandling outside of 48/72 hours. Where just a minor adjustment in timing and/or placement can significantly change the evolution at 500's and consequently the surface reflection/low. In consideration of the above this could very well be a case of where the models don't really pick up on any potential storm until 24/48 hours before game time.

 

Now, I am not calling for a snow storm, far from it. All I am doing is stating that I can see the potential.  I might write up something in the next 24/48 hours if we are still seeing the same general setup they have at this time. Until then I won't waste my time on something that I currently consider low orders of probability.

[paweather]

Interesting a little Ice Storm on New Years:

[CarlislePaWx]

Quick review from 12Z GFS & NAM.  GFS has total qpf for the late Thursday through Friday evening of 0.85".  Of that, it shows almost a perfect 50/50 split with 0.39" of freezing rain falling between Fri 12Z and 18Z and a temp of 30 to 31 degrees.  Then in the next six hours it shows 0.46" of rain with early temp of 33, rising to 36 by 0Z Sat.

NAM has total qpf of about 0.5" through 0Z Sat and is 3 to 6 hours slower with the whole event.  It gives 0.2" of freezing rain mainly between 18Z and 21Z Friday and a temp of 31 to 32, followed by 0.3" of rain with a temp of 33 degrees at the end of the run 0Z Sat.  It looks like there might be another period of rain between 0Z Sat and 6Z Sat, but probably no more than an additional 0.1".

So, both models are showing an ice storm to ring in the new year during the morning into the afternoon Friday.  I'm sure it will change, of course, but I thought I'd throw in my 2 cents of analysis since I had nothing better to do...lol.

[MAG5035]

5 minutes ago, CarlislePaWx said:

Quick review from 12Z GFS & NAM.  GFS has total qpf for the late Thursday through Friday evening of 0.85".  Of that, it shows almost a perfect 50/50 split with 0.39" of freezing rain falling between Fri 12Z and 18Z and a temp of 30 to 31 degrees.  Then in the next six hours it shows 0.46" of rain with early temp of 33, rising to 36 by 0Z Sat.

NAM has total qpf of about 0.5" through 0Z Sat and is 3 to 6 hours slower with the whole event.  It gives 0.2" of freezing rain mainly between 18Z and 21Z Friday and a temp of 31 to 32, followed by 0.3" of rain with a temp of 33 degrees at the end of the run 0Z Sat.  It looks like there might be another period of rain between 0Z Sat and 6Z Sat, but probably no more than an additional 0.1".

So, both models are showing an ice storm to ring in the new year during the morning into the afternoon Friday.  I'm sure it will change, of course, but I thought I'd throw in my 2 cents of analysis since I had nothing better to do...lol.

Models have been pretty solid on this threat for the last couple days once they started sticking that high pressure to our north. The high itself has gotten stronger on the progs too as we've gotten closer. It's a pretty good setup for a straight-up ice event, especially in the interior counties. Mid-levels are easily shot already lacking much cold aloft and the system cutting well west. The fairly strong high solidly anchors the sufficient cold we do have in the low levels. The cutting low pressure is weakening as if lifts northward, so it may draw out the ice longer in the central counties. I'd say this is probably an area-wide advisory event in the making, and potentially a WSW worthy one in interior central/north central PA, dependent on QPF and if sleet is a more predominant p-type during the first part of the event.

Canadian joined the Euro today having that kicker system right behind this potential ice event. Both were very marginal in their cold air availability for snow (Canadian somewhat better). 

[Ruin]

I so dont like Ice i can take sleet but frz rain yuck

[paweather]

5 hours ago, Ruin said:

I so dont like Ice i can take sleet but frz rain yuck

GFS model has backed off a bit for SCPA on the ice threat 0z and 6z both show the high to the north being pushed out quicker. We will see what today brings. 

[Itstrainingtime]

@anotherman I agree with you 100% on the post you made in the other thread about the build up and anticipation of a snowstorm. The analogy of Christmas is  spot on as well. I enjoy the hunt every bit as much if not more than the storm itself. 

[kerplunk]

13 minutes ago, Itstrainingtime said:

@anotherman I agree with you 100% on the post you made in the other thread about the build up and anticipation of a snowstorm. The analogy of Christmas is  spot on as well. I enjoy the hunt every bit as much if not more than the storm itself. 

Can always live vicariously through the models and no matter what actually happens...there’s always the next model run.

Reality can be so boring!    

[anotherman]

21 minutes ago, Itstrainingtime said:

@anotherman I agree with you 100% on the post you made in the other thread about the build up and anticipation of a snowstorm. The analogy of Christmas is  spot on as well. I enjoy the hunt every bit as much if not more than the storm itself. 

Yeah, it's the rush that we all love, I think.  Don't get me wrong, I love being out in the snow and the winter landscape, but the countdown to a big storm is just so much fun.

[canderson]

Ice storms are (thankfully) the unicorn of weather forecasts. 

[Jns2183]

Ice storms are (thankfully) the unicorn of weather forecasts. 

When’s the last time we had a region wide extreme ice event. 2008? When 78 turned into a 100 mile ice skating ring


.

[paweather]

Happy Hour bringing back the January 3rd idea of course too warm right now:

[Superstorm]

Happy Hour bringing back the January 3rd idea of course too warm right now:

Cold is lacking but there may be “just enough”. Something to watch.


.

[Blizzard of 93]

The 18z GFS & GEFS showed a lot more interest on the Sunday snow potential for most of CTP.
A few degrees and a good track will make all of the difference with this storm.

Hopefully it will be just cold enough to cash in on a few inches of snow on Sunday!

[MAG5035]

Currently getting a brief period of steady snow early this morning, ahead of what's looking like a really icy New Year's Day later on tomorrow around here.  

[showmethesnow]

Admittedly my excitement level has increased this last week after each day of runs. But last night's run of the EPS has me over the moon. And the EPS is not on an island as both the GEFS and the CMC are extremely similar.

When I see this, the whole of Canada torching with cold anomalies under riding it through almost the whole of the CONUS...

And please, no references to how this sucks because our source region for cold air is on fire. Doesn't matter here.

 

Then I see this... The PAC firehouse which has been blasting the west coast and overwhelming the flow through the CONUS is pulling westward and weakening in the extended. And the southern/subtropical jet, which has been active, is now aligning up and off the east coast and planting around day 10 in a very favorable local, all the while strengthening as we move forward in time. 

 

The two maps portend well for what we would actually see at 500 mbs. And they did not disappoint. I think we would be hard pressed to find a better look then what the EPS (and other models) are now throwing out. This is a seven day mean from day 8 to 15. As we can see there is massive blocking now projected over almost all of Canada. This will tend to force the storm track farther south through the CONUS. If you look over Alaska and was hinted at by the PAC jet, we see that the PV has shifted west so subsequently energy/storms revolving around it have shifted west as well. This is a favorable local as it will help to pump up heights in western Canada. In the western CONUS we now have ridging/higher heights from subtropical regions extending all the way up into Canada. The importance of this is twofold. It sets up a delivery of cold air into the central US which will be pushed eastward underneath the blocking through Canada. It also is playing a part in bumping up the southern jet from the Gulf and up the East coast which provides moisture as well as potentially injecting southern stream energy into any potential storm. As you can see, we have lower pressures over the southern states and the Gulf and it is exactly where we want to see them. If you note they are extending eastward trying to connect with lower pressures in the north Atlantic. This is a signature look for storminess in the east. You may say the lower pressures  (pseudo 50/50) in the N-Atlantic are too far to the south and east for our needs. But no, in this case they are exactly where we want to see them when considering the given projected pattern. Now when it comes to snow there is always a degree of luck involved in the East. But really, this is a winning look for our chances. It doesn't get much better then this.

 

 

If it wasn't exciting enough to see the above for the day 8 to 15 period, what really should excite you is that this will more then likely be a very stable pattern. This is a pattern that could potentially last for quite an extended period of time. So what would I expect given the above? In my opinion this argues for the axis of heaviest snow being centered around the mid-Atlantic. Somewhere between New York city down to Richmond. This could very well be a case where those in NE are smoking cirrus time and again, especially away from the coast, and those in DC/Balt/Philly are exhausted from shoveling 1-2+ feet of snow time and again. 

Now some people throw out comparisons to glorious previous winters at the drop of the hat. I don't. I believe that each winter is unique in its own way. So though there may be similarities there are also differences. Differences that can have a big say on the final outcome. That said, the similarities we are now seeing are striking to a previous winter. Dare I say 09/10? 

Below we have the mean for the month of Feb 2010. I want you to compare this to the above 7 day mean from the EPS. They are eerily similar. Now some may look at the lower pressure anomalies on the 7 day mean above and say it doesn't quite match up to Feb 2010. Let me just say, if we were to run that 7 day mean forward for another 2 1/2 weeks (to give us a full month) I would put good money that this is the look (lower pressures in the east and off the coast) we would end up with as the storminess kicked in.  

 

 

Now there is always a degree of luck involved when it comes to snow. But if the above projected pattern is in fact what we see, I very much like our chances as we are rolling with the equivalent of loaded dice that come up 7's almost every time. 

[paweather]

2 hours ago, showmethesnow said:

Admittedly my excitement level has increased this last week after each day of runs. But last night's run of the EPS has me over the moon. And the EPS is not on an island as both the GEFS and the CMC are extremely similar.

When I see this, the whole of Canada torching with cold anomalies under riding it through almost the whole of the CONUS...

And please, no references to how this sucks because our source region for cold air is on fire. Doesn't matter here.

 

Then I see this... The PAC firehouse which has been blasting the west coast and overwhelming the flow through the CONUS is pulling westward and weakening in the extended. And the southern/subtropical jet, which has been active, is now aligning up and off the east coast and planting around day 10 in a very favorable local, all the while strengthening as we move forward in time. 

 

The two maps portend well for what we would actually see at 500 mbs. And they did not disappoint. I think we would be hard pressed to find a better look then what the EPS (and other models) are now throwing out. This is a seven day mean from day 8 to 15. As we can see there is massive blocking now projected over almost all of Canada. This will tend to force the storm track farther south through the CONUS. If you look over Alaska and was hinted at by the PAC jet, we see that the PV has shifted west so subsequently energy/storms revolving around it have shifted west as well. This is a favorable local as it will help to pump up heights in western Canada. In the western CONUS we now have ridging/higher heights from subtropical regions extending all the way up into Canada. The importance of this is twofold. It sets up a delivery of cold air into the central US which will be pushed eastward underneath the blocking through Canada. It also is playing a part in bumping up the southern jet from the Gulf and up the East coast which provides moisture as well as potentially injecting southern stream energy into any potential storm. As you can see, we have lower pressures over the southern states and the Gulf and it is exactly where we want to see them. If you note they are extending eastward trying to connect with lower pressures in the north Atlantic. This is a signature look for storminess in the east. You may say the lower pressures  (pseudo 50/50) in the N-Atlantic are too far to the south and east for our needs. But no, in this case they are exactly where we want to see them when considering the given projected pattern. Now when it comes to snow there is always a degree of luck involved in the East. But really, this is a winning look for our chances. It doesn't get much better then this.

 

 

If it wasn't exciting enough to see the above for the day 8 to 15 period, what really should excite you is that this will more then likely be a very stable pattern. This is a pattern that could potentially last for quite an extended period of time. So what would I expect given the above? In my opinion this argues for the axis of heaviest snow being centered around the mid-Atlantic. Somewhere between New York city down to Richmond. This could very well be a case where those in NE are smoking cirrus time and again, especially away from the coast, and those in DC/Balt/Philly are exhausted from shoveling 1-2+ feet of snow time and again. 

Now some people throw out comparisons to glorious previous winters at the drop of the hat. I don't. I believe that each winter is unique in its own way. So though there may be similarities there are also differences. Differences that can have a big say on the final outcome. That said, the similarities we are now seeing are striking to a previous winter. Dare I say 09/10? 

Below we have the mean for the month of Feb 2010. I want you to compare this to the above 7 day mean from the EPS. They are eerily similar. Now some may look at the lower pressure anomalies on the 7 day mean above and say it doesn't quite match up to Feb 2010. Let me just say, if we were to run that 7 day mean forward for another 2 1/2 weeks (to give us a full month) I would put good money that this is the look (lower pressures in the east and off the coast) we would end up with as the storminess kicked in.  

 

 

Now there is always a degree of luck involved when it comes to snow. But if the above projected pattern is in fact what we see, I very much like our chances as we are rolling with the equivalent of loaded dice that come up 7's almost every time. 

Excitement thanks for the post. 

[MAG5035]

50 minutes ago, showmethesnow said:

Admittedly my excitement level has increased this last week after each day of runs. But last night's run of the EPS has me over the moon. And the EPS is not on an island as both the GEFS and the CMC are extremely similar.

When I see this, the whole of Canada torching with cold anomalies under riding it through almost the whole of the CONUS...

And please, no references to how this sucks because our source region for cold air is on fire. Doesn't matter here.

 

 

Then I see this... The PAC firehouse which has been blasting the west coast and overwhelming the flow through the CONUS is pulling westward and weakening in the extended. And the southern/subtropical jet, which has been active, is now aligning up and off the east coast and planting around day 10 in a very favorable local, all the while strengthening as we move forward in time. 

 

 

The two maps portend well for what we would actually see at 500 mbs. And they did not disappoint. I think we would be hard pressed to find a better look then what the EPS (and other models) are now throwing out. This is a seven day mean from day 8 to 15. As we can see there is massive blocking now projected over almost all of Canada. This will tend to force the storm track farther south through the CONUS. If you look over Alaska and was hinted at by the PAC jet, we see that the PV has shifted west so subsequently energy/storms revolving around it have shifted west as well. This is a favorable local as it will help to pump up heights in western Canada. In the western CONUS we now have ridging/higher heights from subtropical regions extending all the way up into Canada. The importance of this is twofold. It sets up a delivery of cold air into the central US which will be pushed eastward underneath the blocking through Canada. It also is playing a part in bumping up the southern jet from the Gulf and up the East coast which provides moisture as well as potentially injecting southern stream energy into any potential storm. As you can see, we have lower pressures over the southern states and the Gulf and it is exactly where we want to see them. If you note they are extending eastward trying to connect with lower pressures in the north Atlantic. This is a signature look for storminess in the east. You may say the lower pressures  (pseudo 50/50) in the N-Atlantic are too far to the south and east for our needs. But no, in this case they are exactly where we want to see them when considering the given projected pattern. Now when it comes to snow there is always a degree of luck involved in the East. But really, this is a winning look for our chances. It doesn't get much better then this.

 

 

 

If it wasn't exciting enough to see the above for the day 8 to 15 period, what really should excite you is that this will more then likely be a very stable pattern. This is a pattern that could potentially last for quite an extended period of time. So what would I expect given the above? In my opinion this argues for the axis of heaviest snow being centered around the mid-Atlantic. Somewhere between New York city down to Richmond. This could very well be a case where those in NE are smoking cirrus time and again, especially away from the coast, and those in DC/Balt/Philly are exhausted from shoveling 1-2+ feet of snow time and again. 

Now some people throw out comparisons to glorious previous winters at the drop of the hat. I don't. I believe that each winter is unique in its own way. So though there may be similarities there are also differences. Differences that can have a big say on the final outcome. That said, the similarities we are now seeing are striking to a previous winter. Dare I say 09/10? 

Below we have the mean for the month of Feb 2010. I want you to compare this to the above 7 day mean from the EPS. They are eerily similar. Now some may look at the lower pressure anomalies on the 7 day mean above and say it doesn't quite match up to Feb 2010. Let me just say, if we were to run that 7 day mean forward for another 2 1/2 weeks (to give us a full month) I would put good money that this is the look (lower pressures in the east and off the coast) we would end up with as the storminess kicked in.  

 

 

 

Now there is always a degree of luck involved when it comes to snow. But if the above projected pattern is in fact what we see, I very much like our chances as we are rolling with the equivalent of loaded dice that come up 7's almost every time. 

Generally in agreement here. While not completely flipping the EPO, ensembles have been at least neutralizing it some as it's gotten out past next week. It's a key thing to happen, because we do have an issue of source region of cold initially which likely manifests in the coastal later this week probably not getting cold enough at the low levels for much snow in PA (more likely toward interior NY/New England) and probably the next system of note that comes about later next week. But you can see it on the models.. once they build any semblance of higher heights on/just off the west coast, it's enough to get the eastern US right where we want it. With that block over the top, we don't really need a raging -EPO ridge to succeed (though an EPO ridge would be nice). We just need to tone down the Pac jet enough as to not flood the CONUS with Pacific air under this awesome block we have materializing in the NAO/AO realm. I'm pretty confident were going to get there.. it just might be around week 2 of Jan or so where we really start seeing this. 

The 09/10 comparison is relevant here.. simply because we haven't seen that kind of a strong and stable NAO/AO blocking regime since 09/10 and the early part of the 10/11 winter. What I'm curious to see is where the obvious differences between this winter and that winter take us. Of course the big difference is we're working a solid La Nina vs 09/10's solid Nino. The other thing is the SST anomalies in the north Pacific. I was going to post about this earlier in the month, but then the big snowstorm showed up and that was the big topic. But pretty much when comparing past Nina's of the last 25 years+, you won't find one with the + anomalies in the N Pacific that this one has. Most of them are quite cold there. The most recent Nina in 2017-18 is about the closest comparison but still had more colder water.

My big worry initially when seeing anomalies like this going into the winter was the assumption of not much help from the NAO/AO and seeing hostile teleconnections from the Pac side materialize. One could see the potential torch in the making. The blocking is a game changer, and now suddenly one can see the potential from an active pattern and suppressed storm track from the blocking. Back to 09-10, here's what that looked like at this point.

The Atlantic and the Gulf of Mexico got even colder with respect to average when February rolled around. But yea, huge difference in SST makeup. I tend to suspect that the much warmer N Atlantic this year might help keep a tighter storm track to the coast and you might not see quite the suppression you saw in the 09-10 winter, which was certainly less memorable in New England.. or Williamsport for that matter if we're talking about this particular subforum haha. There were some folks in here that got next to nothing from Feb 5-6, 2010. It's going to be interesting to see how all this shakes out going through January. If we hang onto the -NAO/AO regime we're definitely going to have chances.  

[paweather]

39 minutes ago, MAG5035 said:

Generally in agreement here. While not completely flipping the EPO, ensembles have been at least neutralizing it some as it's gotten out past next week. It's a key thing to happen, because we do have an issue of source region of cold initially which likely manifests in the coastal later this week probably not getting cold enough at the low levels for much snow in PA (more likely toward interior NY/New England) and probably the next system of note that comes about later next week. But you can see it on the models.. once they build any semblance of higher heights on/just off the west coast, it's enough to get the eastern US right where we want it. With that block over the top, we don't really need a raging -EPO ridge to succeed (though an EPO ridge would be nice). We just need to tone down the Pac jet enough as to not flood the CONUS with Pacific air under this awesome block we have materializing in the NAO/AO realm. I'm pretty confident were going to get there.. it just might be around week 2 of Jan or so where we really start seeing this. 

The 09/10 comparison is relevant here.. simply because we haven't seen that kind of a strong and stable NAO/AO blocking regime since 09/10 and the early part of the 10/11 winter. What I'm curious to see is where the obvious differences between this winter and that winter take us. Of course the big difference is we're working a solid La Nina vs 09/10's solid Nino. The other thing is the SST anomalies in the north Pacific. I was going to post about this earlier in the month, but then the big snowstorm showed up and that was the big topic. But pretty much when comparing past Nina's of the last 25 years+, you won't find one with the + anomalies in the N Pacific that this one has. Most of them are quite cold there. The most recent Nina in 2017-18 is about the closest comparison but still had more colder water.

My big worry initially when seeing anomalies like this going into the winter was the assumption of not much help from the NAO/AO and seeing hostile teleconnections from the Pac side materialize. One could see the potential torch in the making. The blocking is a game changer, and now suddenly one can see the potential from an active pattern and suppressed storm track from the blocking. Back to 09-10, here's what that looked like at this point.

The Atlantic and the Gulf of Mexico got even colder with respect to average when February rolled around. But yea, huge difference in SST makeup. I tend to suspect that the much warmer N Atlantic this year might help keep a tighter storm track to the coast and you might not see quite the suppression you saw in the 09-10 winter, which was certainly less memorable in New England.. or Williamsport for that matter if we're talking about this particular subforum haha. There were some folks in here that got next to nothing from Feb 5-6, 2010. It's going to be interesting to see how all this shakes out going through January. If we hang onto the -NAO/AO regime we're definitely going to have chances.  

Thanks Mag! Great write ups both of you. 

[so_whats_happening]

55 minutes ago, MAG5035 said:

Generally in agreement here. While not completely flipping the EPO, ensembles have been at least neutralizing it some as it's gotten out past next week. It's a key thing to happen, because we do have an issue of source region of cold initially which likely manifests in the coastal later this week probably not getting cold enough at the low levels for much snow in PA (more likely toward interior NY/New England) and probably the next system of note that comes about later next week. But you can see it on the models.. once they build any semblance of higher heights on/just off the west coast, it's enough to get the eastern US right where we want it. With that block over the top, we don't really need a raging -EPO ridge to succeed (though an EPO ridge would be nice). We just need to tone down the Pac jet enough as to not flood the CONUS with Pacific air under this awesome block we have materializing in the NAO/AO realm. I'm pretty confident were going to get there.. it just might be around week 2 of Jan or so where we really start seeing this. 

The 09/10 comparison is relevant here.. simply because we haven't seen that kind of a strong and stable NAO/AO blocking regime since 09/10 and the early part of the 10/11 winter. What I'm curious to see is where the obvious differences between this winter and that winter take us. Of course the big difference is we're working a solid La Nina vs 09/10's solid Nino. The other thing is the SST anomalies in the north Pacific. I was going to post about this earlier in the month, but then the big snowstorm showed up and that was the big topic. But pretty much when comparing past Nina's of the last 25 years+, you won't find one with the + anomalies in the N Pacific that this one has. Most of them are quite cold there. The most recent Nina in 2017-18 is about the closest comparison but still had more colder water.

My big worry initially when seeing anomalies like this going into the winter was the assumption of not much help from the NAO/AO and seeing hostile teleconnections from the Pac side materialize. One could see the potential torch in the making. The blocking is a game changer, and now suddenly one can see the potential from an active pattern and suppressed storm track from the blocking. Back to 09-10, here's what that looked like at this point.

The Atlantic and the Gulf of Mexico got even colder with respect to average when February rolled around. But yea, huge difference in SST makeup. I tend to suspect that the much warmer N Atlantic this year might help keep a tighter storm track to the coast and you might not see quite the suppression you saw in the 09-10 winter, which was certainly less memorable in New England.. or Williamsport for that matter if we're talking about this particular subforum haha. There were some folks in here that got next to nothing from Feb 5-6, 2010. It's going to be interesting to see how all this shakes out going through January. If we hang onto the -NAO/AO regime we're definitely going to have chances.  

 

That is a huge worry of mine as well but great write up. The possibilities with this could very interesting! Excited to see how the next 2 weeks unfolds.

[so_whats_happening]

4 hours ago, showmethesnow said:

Admittedly my excitement level has increased this last week after each day of runs. But last night's run of the EPS has me over the moon. And the EPS is not on an island as both the GEFS and the CMC are extremely similar.

When I see this, the whole of Canada torching with cold anomalies under riding it through almost the whole of the CONUS...

And please, no references to how this sucks because our source region for cold air is on fire. Doesn't matter here.

 

Then I see this... The PAC firehouse which has been blasting the west coast and overwhelming the flow through the CONUS is pulling westward and weakening in the extended. And the southern/subtropical jet, which has been active, is now aligning up and off the east coast and planting around day 10 in a very favorable local, all the while strengthening as we move forward in time. 

 

The two maps portend well for what we would actually see at 500 mbs. And they did not disappoint. I think we would be hard pressed to find a better look then what the EPS (and other models) are now throwing out. This is a seven day mean from day 8 to 15. As we can see there is massive blocking now projected over almost all of Canada. This will tend to force the storm track farther south through the CONUS. If you look over Alaska and was hinted at by the PAC jet, we see that the PV has shifted west so subsequently energy/storms revolving around it have shifted west as well. This is a favorable local as it will help to pump up heights in western Canada. In the western CONUS we now have ridging/higher heights from subtropical regions extending all the way up into Canada. The importance of this is twofold. It sets up a delivery of cold air into the central US which will be pushed eastward underneath the blocking through Canada. It also is playing a part in bumping up the southern jet from the Gulf and up the East coast which provides moisture as well as potentially injecting southern stream energy into any potential storm. As you can see, we have lower pressures over the southern states and the Gulf and it is exactly where we want to see them. If you note they are extending eastward trying to connect with lower pressures in the north Atlantic. This is a signature look for storminess in the east. You may say the lower pressures  (pseudo 50/50) in the N-Atlantic are too far to the south and east for our needs. But no, in this case they are exactly where we want to see them when considering the given projected pattern. Now when it comes to snow there is always a degree of luck involved in the East. But really, this is a winning look for our chances. It doesn't get much better then this.

 

 

If it wasn't exciting enough to see the above for the day 8 to 15 period, what really should excite you is that this will more then likely be a very stable pattern. This is a pattern that could potentially last for quite an extended period of time. So what would I expect given the above? In my opinion this argues for the axis of heaviest snow being centered around the mid-Atlantic. Somewhere between New York city down to Richmond. This could very well be a case where those in NE are smoking cirrus time and again, especially away from the coast, and those in DC/Balt/Philly are exhausted from shoveling 1-2+ feet of snow time and again. 

Now some people throw out comparisons to glorious previous winters at the drop of the hat. I don't. I believe that each winter is unique in its own way. So though there may be similarities there are also differences. Differences that can have a big say on the final outcome. That said, the similarities we are now seeing are striking to a previous winter. Dare I say 09/10? 

Below we have the mean for the month of Feb 2010. I want you to compare this to the above 7 day mean from the EPS. They are eerily similar. Now some may look at the lower pressure anomalies on the 7 day mean above and say it doesn't quite match up to Feb 2010. Let me just say, if we were to run that 7 day mean forward for another 2 1/2 weeks (to give us a full month) I would put good money that this is the look (lower pressures in the east and off the coast) we would end up with as the storminess kicked in.  

 

 

Now there is always a degree of luck involved when it comes to snow. But if the above projected pattern is in fact what we see, I very much like our chances as we are rolling with the equivalent of loaded dice that come up 7's almost every time. 

I like the setup potential but am really curious as well how this sets up. I would almost argue it may have more of a positive tilt to it with the extended ridging potential with such warm SSTs in the Atlantic. I wouldnt call it a progressive at all, just really hope suppression doesnt become a thing, but overall just really interested what this setup will yield. Great write up though! Whatever is coming sure does look fun though.