November/December Medium/Long Range Disco

[Yeoman]

31 minutes ago, Ji said:

is anyone interested in the wave that is heading towards the mid atlantic friday. If it dosent shear out--we could see some light snow

People are more interested in fantasy range weekly index forecasts which shift 10 times before locking in 4 days before the date.

[Bob Chill]

1 minute ago, cbmclean said:

Visitor from the SE forum here.  I am obviously uneducated, but I was curious, even with the BN heights in Alaska, isn't it also showing forecasting BN heights in the East.  And isn't that a good thing?

It works later in the winter season but in early Dec it generally means not enough cold air for both our regions. Pacific air floods Canada or the western conus. A ridge in that same region builds very cold air in our source region. 

[showmethesnow]

5 minutes ago, cbmclean said:

Visitor from the SE forum here.  I am obviously uneducated, but I was curious, even with the BN heights in Alaska, isn't it also showing forecasting BN heights in the East.  And isn't that a good thing?

I always want to see BN heights and troughing centered in the East. Its pretty much the first thing I check. The problem with BN heights in Alaska is that we typically get a flow off the Pacific which normally doesn't cut it this early in the season temp wise. Later in the season we can overcome it but now not so much. 

[Scud]

41 minutes ago, Ji said:

is anyone interested in the wave that is heading towards the mid atlantic friday. If it dosent shear out--we could see some light snow

We will be looking, update soon.

[cbmclean]

5 minutes ago, showmethesnow said:

I always want to see BN heights and troughing centered in the East. Its pretty much the first thing I check. The problem with BN heights in Alaska is that we typically get a flow off the Pacific which normally doesn't cut it this early in the season temp wise. Later in the season we can overcome it but now not so much. 

Anyone on here interested in briefly explaining the physical mechanism by which height anomalies and temp anomalies are associated?  It is something which has troubled me for years.  Clearly heights and temperatures are correlated.  AN heights tend to be associated with AN temps and vice versa. 

[Scud]

Crickets 

[CAPE]

1 hour ago, Ji said:

is anyone interested in the wave that is heading towards the mid atlantic friday. If it dosent shear out--we could see some light snow

As modeled its too close on the heels of the exiting upper low, so that s/w is likely going to dampen with little chance of surface development as it moves east.

[Scud]

GFS looks better but still has two short waves. They are closer together this run.

[CAPE]

49 minutes ago, cbmclean said:

Anyone on here interested in briefly explaining the physical mechanism by which height anomalies and temp anomalies are associated?  It is something which has troubled me for years.  Clearly heights and temperatures are correlated.  AN heights tend to be associated with AN temps and vice versa. 

In a nutshell, the 500 mb level is higher in the atmosphere when the air beneath is it warmer- warm air is less dense- takes up more volume. The opposite is true when the air is colder- its more dense, or compacted, so the 500 mb height is lower in the atmosphere. You can read 500 mb height/anomaly panels sort of like a topo map.

[cbmclean]

22 minutes ago, C.A.P.E. said:

In a nutshell, the 500 mb level is higher in the atmosphere when the air beneath is it warmer- warm air is less dense- takes up more volume. The opposite is true when the air is colder- its more dense, or compacted, so the 500 mb height is lower in the atmosphere. You can read 500 mb height anomalies sort of like a topo map.

C.A.P.E

 

Thank you for this.

This is the exact understanding that I had from listening other's talk on here and reading a bit of simple stuff online.

However, from the EPS 360 hr map that was posted above the below normal 500 dm anomalies stretched all the way from Alaska through the NWT/Nunavut, down through Ontario into the Eastern US.  So by my understanding, below normal 500 dm heights should equate to BN temps in all of those areas.  So BN heights in northern Canada should equal BN temps there according to the simplified model that I have in my head.  I would expect if Canada was being flooded with mild Pacific air i would see red anomalies up there. 

Can you explain where I am going off the track?

[Scud]

21 minutes ago, cbmclean said:

C.A.P.E

 

Thank you for this.

This is the exact understanding that I had from listening other's talk on here and reading a bit of simple stuff online.

However, from the EPS 360 hr map that was posted above the below normal 500 dm anomalies stretched all the way from Alaska through the NWT/Nunavut, down through Ontario into the Eastern US.  So by my understanding, below normal 500 dm heights should equate to BN temps in all of those areas.  So BN heights in northern Canada should equal BN temps there according to the simplified model that I have in my head.  I would expect if Canada was being flooded with mild Pacific air i would see red anomalies up there. 

Can you explain where I am going off the track?

The warm air is not necessarily at the surface.

[CAPE]

34 minutes ago, cbmclean said:

C.A.P.E

 

Thank you for this.

This is the exact understanding that I had from listening other's talk on here and reading a bit of simple stuff online.

However, from the EPS 360 hr map that was posted above the below normal 500 dm anomalies stretched all the way from Alaska through the NWT/Nunavut, down through Ontario into the Eastern US.  So by my understanding, below normal 500 dm heights should equate to BN temps in all of those areas.  So BN heights in northern Canada should equal BN temps there according to the simplified model that I have in my head.  I would expect if Canada was being flooded with mild Pacific air i would see red anomalies up there. 

Can you explain where I am going off the track?

Depends on the orientation/location/depth of the trough. If the trough were deeper and centered more over the GOA, it would be quite a warmer look up there. Also while h5 heights do correlate fairly well to temps at lower levels in the atmosphere, it doesn't give the whole picture. Look at 850 and surface as well. Another thing- that is a panel for a day 15 ens mean, so its pretty smoothed/low resolution.

[cbmclean]

9 minutes ago, C.A.P.E. said:

Depends on the orientation/location/depth of the trough. If the trough were deeper and centered more over the GOA, it would be quite a warmer look up there. Also while h5 heights do correlate fairly well to temps at lower levels in the atmosphere, it doesn't give the whole picture. Look at 850 and surface as well. Another thing- that is a panel for a day 15 ens mean, so its pretty smoothed/low resolution.

I appreciate your taking the time to pass along some knowledge.

[AfewUniversesBelowNormal]

I'm surprised that no one has said the -PNA shown on long term models is going to be difficult to do in El Nino. 

[EastCoast NPZ]

11 minutes ago, WxWatcher007 said:

Just sit back and read from one of the best on the site. We’re fine.

 

In other words, expect our rain to be colder than normal.

[NorthArlington101]

12z ICON has a healthy system move through Fri-Sat. Nice 1-3"er in Central VA, .5"-1" for NOVA/MD.

 

[BristowWx]

6 minutes ago, NorthArlington101 said:

12z ICON has a healthy system move through Fri-Sat. Nice 1-3"er in Central VA, .5"-1" for NOVA/MD.

 

That would work.  North trend and we jackpot.  Or it washes out.  Psu would get fringed....always.

[BTRWx's Thanks Giving]

4 hours ago, C.A.P.E. said:

Looking at all the current guidance, the reality is Dec will probably be pretty changeable. Still have to think the NPAC will get "right" at some point. AO looks good for now. I don't see much to worry over yet. This is a relatively late starting Nino (compared to say 2009 when official Nino status was achieved by August IIRC), so just a guess on my part, but it may take some time before the atmosphere completely responds and locks into more typical Nino behavior. Most of the winter forecasts were indicative of that, with things really getting going in January. 

It's interesting to have the Modoki signal along wiht the north Pacific warm ssta blob.  That's rare.

[BTRWx's Thanks Giving]

2002-2003 is looking better every day.

[paulythegun]

Let's check in on how the GFS operational models are handling the long ra.....

Oh

Sent from my SM-N950U using Tapatalk

[frd]

12 minutes ago, paulythegun said:

Let's check in on how the GFS operational models are handling the long ra.....

Oh

Sent from my SM-N950U using Tapatalk
 

The deeper we get into December the better I feel that our chances improve. 

Simple and stress free hopefully! 

[cbmclean]

1 hour ago, paulythegun said:

Let's check in on how the GFS operational models are handling the long ra.....

Oh

Sent from my SM-N950U using Tapatalk
 

Well, if you inverted one of them, they would be kind of similar. 

I would be tempted to discard the FV out of hand.  I think we know that that sort of coast-to-coast cold anomaly is pretty much physically impossible.  You can be coast-to-coast warm, but not cold.

[Scraff]

Happy Hour GFS brings the goods next Friday!  It’s on. 

[Scud]

Totals, NW flow relaxed.

[NoVaWx]

31 minutes ago, Scud said:

Totals, NW flow relaxed.

Not bad looks like a widespread 1-3” at least something to track I guess sometimes these things can juice up and give 5” last minute. 

[CAPE]

Happy Hour GFS with multiple teases in the Dec 3-10 window.

[MJO812]

6 minutes ago, C.A.P.E. said:

Happy Hour GFS with multiple teases in the Dec 3-10 window.

Pattern fits it

[psuhoffman]

21 minutes ago, C.A.P.E. said:

Happy Hour GFS with multiple teases in the Dec 3-10 window.

I'm going to love it if this year is like 2013-14 in that we trend our way into multiple events inside medium range. I think some believe I like to look long range. But that's because the last few years most of the winter there was nothing to look at in the short medium range.  And the few times I've cherry picked and hyped a storm threat from long range it was a pretty "obvious" thing to do. Those threats in 2009/10 were pretty apparent from 10-14 days out to many. The threat in January 2011 as the blocking broke down was pretty apparent too from range. And EVERYONE saw the 2016 threat from range. But 90% of our snow threats don't come from perfect hecs setups and aren't apparent 10 days out.  I would like a winter where storms smack us in the face while we're looking down the road and the long range thread is tame because we're too jusy in the storm and obs threads to bother with the euro weeklies and over analyzing  day 15 ensembles run to run. 

[Bob Chill]

27 minutes ago, C.A.P.E. said:

Happy Hour GFS with multiple teases in the Dec 3-10 window.

The pac nw troughing and general ensemble look isn't a shutout pattern but it does seriously hinder any type of large/organized storm. Any strong shortwave would most likely if not definitely cut to our west. And being so early in snow climo it would be pretty tough to get a front end/cad type of deal. The accum event we already had included a pretty cold antecedent airmass that dropped down from the northern plains. The active pac jet wont let big cold build nearly as easily as the pattern we had earlier this month. 

OTOH- any type of trailing/weaker shortwave after a strong storm cuts could work so imho- things look good enough for early Dec. We're in the game and lots of shortwaves will be running through the flow across the conus. Wouldn't be surprised if the late week deal or anything similar works out over the first 5-10 days of Dec. 

[CAPE]

1 minute ago, Bob Chill said:

The pac nw troughing and general ensemble look isn't a shutout pattern but it does seriously hinder any type of large/organized storm. Any strong shortwave would most likely if not definitely cut to our west. And being so early in snow climo it would be pretty tough to get a front end/cad type of deal. The accum event we already had included a pretty cold antecedent airmass that dropped down from the northern plains. The active pac jet wont let big cold build nearly as easily as the pattern we had earlier this month. 

OTOH- any type of trailing/weaker shortwave after a strong storm cuts could work so imho- things look good enough for early Dec. We're in the game and lots of shortwaves will be running through the flow across the conus. Wouldn't be surprised if the late week deal or anything similar works out over the first 5-10 days of Dec. 

Totally agree. This is likely the only realistic scenario for the MA to score a minor to moderate frozen event with the advertised pattern, and with the parade of shortwaves there will be chances.