It's Always Sunny

Yeah the ECMWF hasn't done well with these shallow, cold air masses which explains why they are leaning colder. NAM could be too cold but I think leaning that way is good at the current lead time.

2-4" for BOS looking more reasonable based off 00Z suite.

Next week's severe weather potential looking good per dry line setup in TX/OK. Low level moisture, CAPE (not shown), kinematics all in place. Not a bad look at all albeit a week out.

Still lots of asymmetric spread but for snow weenies good to see it on the W/NW side. Obviously too far west isn't good but any sign that keeps this thing closer to the coast rather than OTS is a win for the time being.

Had some spare time to put this together. Current modeled output resembles January 26-27, 2015 blizzard. Surprisingly most of these events occurred when the NAO was neutral-positive.

Highs in the 40s isn't cold enough for you? . DFW may get close to 80F I'm loving every bit of it

I think we're close to a lock to break the latest freeze record which is Jan 4th (1972).

Meh on this potential IVT. Sniffing snizzle.

Manch Vegas mixing now

Oh I'm talking about tomorrow night. I was like Will's a smart dude but uh it looks very similar lol.

12Z had a similar look though. 18Z doesn't look much different if we're talking h5

Just saw this after I posted...I agree!

This thread should be renamed to Nov 26-27 Snow Threat much better chance people see snow tomorrow.

You and your ceilings...just like your prediction a couple months ago Boston can get 150+" of snow smh.

If anyone east of 95 in MA is expecting more than 1" you'll be disappointed.

I think this is currently an underplayed system tomorrow night. Quite a few spots from MHT up through PWM could see between 1-3".

Yeah 18Z is nice for you. We just end up with our first freeze of the season here. Still fantasyland though...

12Z GFS...

This is what happens when The Weather Channel (and the media in general) refers to the Polar Vortex so loosely; it creates misconception. They have everyone looking up at 10mb when at 500mb and below is what actually produces most of the time.

I haven't read this article but just goes to show how much more there is to learn. Thanks for the link!

Ok yeah I get what you're saying but I guess the point I was trying to make was there have been a few months during Dec-Apr where IOD was negative and has had some influence on downstream impacts via enhanced Walker Circulation. Obviously what transpires in the IO will have certain amount of time lag before its influence is felt over the Pacific but like mentioned before I think this is an area of research that can be explored more. IO is such a huge driver of our summer weather I would think there is at least some influence (big or not) it has on winter weather, more than what we currently know. There was some research done back in 2015 I think that correlated summer/fall IOD phase to proceeding ENSO phase with 8-14 month lead time. Results weren't entirely accurate but r-values were sound. It didn't pan out this year when referencing last but I believe the year before it did I would have to go back and look. Just shows how "new" all this is.

HM is the go to for this but put very simply it is the amount of westerly momentum (or lack thereof) occurring around the globe. GSDL plots only show what has already happened so you can't really forecast based on that but it gives a snapshot of current conditions (total GLAAM, FT, MT, tendencies, etc). Gensini has a nice webpage that shows AAM forecast but it currently is not up to date. Also has a strong low bias since it is GFS based. To be perfectly honest it's a nice tool to have but if you don't have access to AAM model guidance (which most don't unless you have a high tier WxBell account or if Gensini's site updates), deterministic and ensemble models along with teleconnections are pretty much all you need in my opinion. Here is a post I made yesterday pertaining to AAM & MJO where you can use AAM to support a forecast but without the AAM forecast models themselves it is hard to solely rely on:

I agree but a -IOD can enhance Walker Circulation = more robust convection over Maritime Continent = potentially more robust NPac Jet which can influence what infiltrates the Lower 48. This is one area that I think more research is needed to get a better grasp to specific impacts but from a general understanding this is what transpires.

I think the IO is one of the most underplayed influences in long range forecasting. Meteorologically still more to be discovered but it is a known driver of the NPAC jet which obviously has downstream impacts.

What is the main difference between the two? They both appear to have the same functionality.