January Long Range Disco Thread

[CAPE]

7 minutes ago, psuhoffman said:

Blocking patterns aren’t always cold. Often they are quite mild north of the storm track. This year has been to the extreme though. 

Agree, but read my most recent post. This seems a bit different than what we typically see. Maybe I am wrong though.

[CAPE]

24 minutes ago, Rvarookie said:

Shout out to @CAPE and @psuhoffman for carrying the torch this year. At least it’s been better to read posts this year 

Thanks, but what makes this fun is everyone contributing and sharing info and getting different perspectives. It's a group effort.

[psuhoffman]

10 minutes ago, CAPE said:

Agree, but read my most recent post. This seems a bit different that what we typically see. Maybe I am wrong though.

It just depends. Not all blocking patterns are the same. But a -NAO split flow isn’t uncommon and usually a good thing. It’s not a cold pattern.  Feb 2010 was one. The Polar jet was directed across Canada by the trough in the pac but the southern stream was splitting into the SW and coming across the gulf coast.  But the pac jet wasn’t as intense and the profile in Canada wasn’t as awful to start. But it wasn’t cold. Actually north of us was very mild. And even here it would have been 45 that week had there not been snow.  It’s a pick your poison thing. A split flow cuts off the polar air but normally in winter we can develop a just cold enough airmass under the flow to get snow with a good track. This year that didn’t work out. A -EPO -NAO non split flow is much colder but it can be a dryer pattern if storms dive in too far north to amplify under us and the STJ is cut off in that case. So there are pros and cons to both. FWIW the split flow option accounts for a lot of our HECS storms. 

[cbmclean]

6 minutes ago, CAPE said:

Thanks, but what makes this fun is everyone contributing and sharing info and getting different perspectives. It's a group effort.

GEFS 850 MB temp anomalies still look to improve considerably after Jan 16, both for us and for our source region.  2m anomalies are disappointing though.

[CAPE]

8 minutes ago, psuhoffman said:

It just depends. Not all blocking patterns are the same. But a -NAO split flow isn’t uncommon and usually a good thing. It’s not a cold pattern.  Feb 2010 was one. The Polar jet was directed across Canada by the trough in the pac but the southern streak was splitting into the SW and coming across the gulf coast.  But the pac jet wasn’t as intense and the profile in Canada wasn’t as awful to start. But it wasn’t warm. Actually north of us was very mild. And even here it would have been 45 that week had there not been snow.  It’s a puck your poison thing. A split flow cuts off the polar air but normally in winter we can develop a just cold enough airmass under the flow to get snow with a good track. This year that didn’t work out. A -EPO -NAO non split flow is much colder but it can be a dryer pattern if storms dive in too far north to amplify under us and the STJ is cut off in just case. So there are pros and cons to both. FWIW the split flow option accounts for a lot of our HECS storms. 

Could be just bad luck/bad timing then, or an indication of some longer term changes. Given the HL look we have had, it seemed different to me. Maybe that is partly due to the ground truth here being exactly the same as last winter, despite the HL blocking lol. It will be interesting to see how things play out over the next 10 days or so, when it appears we will have some colder/drier air to work with, and blocking in place. Better luck if nothing else, hopefully.

[CAPE]

12 minutes ago, cbmclean said:

GEFS 850 MB temp anomalies still look to improve considerably after Jan 16, both for us and for our source region.  2m anomalies are disappointing though.

 

Yeah I wouldn't worry too much about the 2m temps as advertised. Just having somewhat colder, lower dp air available will make a big difference. With a -AO/NAO,  we tend to have the highs and lows in the right places, and evaporational cooling can work its magic.

[chris21]

11 minutes ago, cbmclean said:

GEFS 850 MB temp anomalies still look to improve considerably after Jan 16, both for us and for our source region.  2m anomalies are disappointing though.

While they could be right for the wrong reasons I would tend to just look at the 850 mb anomalies. The long range 2m temp anomalies are atrocious to say the least.

[dallen7908]

As snowdreamer noted, the best chance of snow in MBY according to the EPS is on the 20th - could be fun to watch the ... REMINDER: NO ...

While there is nothing through the medium-range, the 15 day mean of 2  - 2 1/2 inches is higher than its been in quite a while.  The 20th is roughly when the PNA is forecast to go negative for a while. 

 

 

[psuhoffman]

8 minutes ago, CAPE said:

Could be just bad luck/bad timing then, or an indication of some longer term changes. Given the HL look we have had, it seemed different to me. Maybe that is partly due to the ground truth here being exactly the same as last winter, despite the HL blocking lol. It will be interesting to see how things play out over the next 10 days or so, when it appears we will have some colder/drier air to work with, and blocking in place. Better luck if nothing else, hopefully.

I think, as wxusaf, that it’s a bit of both bad luck and the background stage becoming incrementally more hostile. In December we had a nice AO ridge but it was a bit north of perfect.  That can work though if you get other things to line up and we almost did but that SW that dive in out west really screwed us by amplifying the trough more. But it’s hard to get a big snow in mid December.  The first iteration of the -NAO this month ended up too extreme imo. That was part of the problem.  I posted this from a couple days ago. 

That ridge is centered way too far south and extends too far SW.  Not only did that suppress 3 waves but it prevents colder air from draining into the pattern to the west of the block.  Center that further north without that extension into Quebec and we get a slightly colder profile and less suppressed systems and I bet one of them “works out”.  This next flex of the blocking looks more ideal but now there are questions about what kind of PAC we get. Ideally I would have liked one more bite of the apple with the current pac and a better NAO. But I don’t have the magic crayon. And the look we see now is pretty darn good. And I’m biased by my location. If I were you I would definitely go with the colder but possibly dryer option. We have way different climo. 

[Siberian-Snowcover-Myth]

Nothing like a mild winter drought in the supposedly greatest hyped up pattern in decades.

[CAPE]

Just now, Siberian-Snowcover-Myth said:

Nothing like a mild winter drought in the supposedly greatest hyped up pattern in decades.

Best since 96!

I wont lie, I have enjoyed this week of dryness. My driveway has solidified again.

[Ralph Wiggum]

1 hour ago, psuhoffman said:

The mean SLP is screaming this kind of result imo!  

Only 360 more hours to go which takes us to the last week in January.  Our patience is truly being tested!

[cbmclean]

14 minutes ago, psuhoffman said:

I think, as wxusaf, that it’s a bit of both bad luck and the background stage becoming incrementally more hostile

Just curious how much impact you think the hostile November had.  You have mentioned it a few times as a negative factor, but was it a MAJOR factor?

[stormtracker]

18z GFS gonna provide some action 200+ hr.  But....200 hr +

[stormtracker]

If you like rain, man have I got something for you.  Darth Lake's Low strikes again.

[JakkelWx]

Merry Christmas 

[wawarriors4]

Just now, stormtracker said:

If you like rain, man have I got something for you

Looks like Christmas Eve looked, but thankfully 220+ hours

[MD Snow]

As others have mentioned, 18z GFS still pointing to January 18-20 as a threat window. That's all you should take from an op run past 200+ hrs. 

[BristowWx]

1 minute ago, wawarriors4 said:

Looks like Christmas Eve looked, but thankfully 220+ hours

Plenty of time for a westward adjustment. And it wouldn’t take much actually.  

[losetoa6]

Snow to rain to snow.  Sign me up .I'm not picky 

[Cobalt]

That 360hr look lol, primary up in Illinois and we’ve got blue over most of the sub forum.
We seem to have flipped from the GFS showing anything but snow over us but of course it will change in just 6 hours


.

[BristowWx]

I wonder if a clean   all snow event is even possible anymore.  Snow to rain to snow is fine but all snow would be fun too. 

[psuhoffman]

Just a little blocking when storms transfer from Indianapolis to Hatteras 

[BristowWx]

2 minutes ago, psuhoffman said:

Just a little blocking when storms transfer from Indianapolis to Hatteras 

Have we ever seen an IN to NC transfer?  Seems like we would remember that 

[psuhoffman]

19 minutes ago, BristowWx said:

Have we ever seen an IN to NC transfer?  Seems like we would remember that 

Recently no. Are there examples of that in the past yes.  It takes a blocking regime and a cold airmass. 

[psuhoffman]

32 minutes ago, BristowWx said:

Have we ever seen an IN to NC transfer?  Seems like we would remember that 

A storm in 1972 transferred from the UP of MI to SC. That was probably the most extreme example. 

[cbmclean]

Just now, psuhoffman said:

A storm in 1972 transferred from the UP of MI to SC. That was probably the most extreme example. 

If you are feeling didactic tonight, what exactly is a "transfer"?  I only have the vaguest idea of storm dynamics.

[Chris78]

56 minutes ago, psuhoffman said:

Just a little blocking when storms transfer from Indianapolis to Hatteras 

It's been so long since  we've had an actual block I think we forget what crazy storm tracks that can cause lol.

That storm on the GFS at 300+ hours out looks like it's going to be Rainer but the block says nope your going south. 

If we can't score the last 10 days of January If this pattern comes to pass, I dont know what to say lol.

[losetoa6]

1 hour ago, psuhoffman said:

A storm in 1972 transferred from the UP of MI to SC. That was probably the most extreme example. 

I'd think Dec 1992,Nov 1950 would be extreme examples of big time negative tilt aided by superb blocking and/or perfectly positioned blocks . Even Sandy possibly 

[Wentzadelphia]

1 hour ago, cbmclean said:

If you are feeling didactic tonight, what exactly is a "transfer"?  I only have the vaguest idea of storm dynamics.

I’ll let others explain better, but basically when a low pressure hits a high pressure and a new low forms. Here is a random map I pulled off google showing the two lows. The secondary is the one forming near the coast.