December 2017 Mid-Long Range Disco

[showmethesnow]

1 minute ago, BristowWx said:

I was cycling through the entire run just to see if there’s any snow whatsoever and that song tragedy came on by The Bee Gees.  That gave me a chuckle.

06Z GFS was actually a good run when looking at the upper levels irregardless of what the surface depiction shows. Just look at the snowfall maps the GEFS is throwing out for the Fri-Sun period which is probably following the ops lead. 

[showmethesnow]

Just now, losetoa6 said:

Just saw 6z gefs actually improved for Fri . ..nice . I think along 95 and east has the best shot .

Upper levels supported that shift westward.

 

[eurojosh]

18 minutes ago, showmethesnow said:

06Z GFS was actually a good run when looking at the upper levels irregardless of what the surface depiction shows. Just look at the snowfall maps the GEFS is throwing out for the Fri-Sun period which is probably following the ops lead. 

Could say we're 

[Puts on sunglasses]

Stayin' Alive. 

[BristowWx]

16 minutes ago, showmethesnow said:

06Z GFS was actually a good run when looking at the upper levels irregardless of what the surface depiction shows. Just look at the snowfall maps the GEFS is throwing out for the Fri-Sun period which is probably following the ops lead. 

You can feel free to crap on my shoe but looking at 500mb vort timestsmp 132 at 0z has closed vort going under us and 6z has less dig and no closed vort which seems to impact the suface.  If I am looking at that wrong then I am a weather tool.  But that’s what I observed.  

[showmethesnow]

2 minutes ago, BristowWx said:

You can feel free to crap on my shoe but looking at 500mb vort timestsmp 132 at 0z has closed vort going under us and 6z has less dig and no closed vort which seems to impact the suface.  If I am looking at that wrong then I am a weather tool.  But that’s what I observed.  

Referring more to the Friday time period. Saw a good improvement there. As far as the upper level energy around Sunday? No freaking idea. That has been all over the place and don't think it will be resolved until we see what happens in the Friday time frame.

eta: This board has a fixation on poop for some reason. Me included. :). 

[BristowWx]

6 minutes ago, showmethesnow said:

Referring more to the Friday time period. Saw a good improvement there. As far as the upper level energy around Sunday? No freaking idea. That has been all over the place and don't think it will be resolved until we see what happens in the Friday time frame.

eta: This board has a fixation on poop for some reason. Me included. :). 

mostly guys here so I would expect that.  My teenage boys think anything to do with poop is funny.  Anyway, I don't think that's the final answer for Sat/Sunday but it does become quite evident the results of 500mb and how it is depicted and what happens at the surface.  My personal feeling is that possibility is a better shot at board wide flakes.  If we can keep that look from 0z (closed and below) then it could be something fun.  But the steaming terd look of the 6z wont cut it (open, forward tilted, north).  Not strong enough to traverse the mountains and we are left with next to nothing.  just my observation.      

[showmethesnow]

After seeing the last few runs of the GFS and the GEFS I am no longer sure what to think for the Fri-Sun period (especially after seeing the 06Z GEFS). The GFS/GEFS runs have been inconsistent with one of the key features, the trough, as well as the energy involved. One of the features I thought it was fairly locked in on was the blocking (upper level flow) to the west of the coastal limiting its ability to move westward as well as roughly the timing of the low popping in the trough of low pressure off the coast. The 06Z pretty much put a wrench into the works for that stability. The GFS/GEFS both saw somewhat significant shifts westward of the blocking upstairs allowing a more westerly track of any possible coastal. The 06 is also delaying development and slowing down the movement somewhat of that coastal which can probably be attributed to the changes we have seen in the southern jet on this run. Now if this shifting of the upper level block west of the coastal is real and the beginning of a trend (GFS bias coming into play?) and not an aberration being thrown out by the 06Z GFS then I like our chances of seeing further shifts west of the coastal track, a little better intensification and a somewhat slower solution. 

As far as the upper level energy rotating through on Sunday. Haven't a clue. Models are all over the place with that feature and what it will probably come down to is what we see with the Friday coastal and its impact on the set up for Sunday.

[BristowWx]

1 minute ago, showmethesnow said:

After seeing the last few runs of the GFS and the GEFS I am no longer sure what to think for the Fri-Sun period (especially after seeing the 06Z GEFS). The GFS/GEFS runs have been inconsistent with one of the key features, the trough, as well as the energy involved. One of the features I thought it was fairly locked in on was the blocking (upper level flow) to the west of the coastal limiting its ability to move westward as well as roughly the timing of the low popping in the trough of low pressure off the coast. The 06Z pretty much put a wrench into the works for that stability. The GFS/GEFS both saw somewhat significant shifts westward of the blocking upstairs allowing a more westerly track of any possible coastal. The 06 is also delaying development and slowing down the movement somewhat of that coastal which can probably be attributed to the changes we have seen in the southern jet on this run. Now if this shifting of the upper level block west of the coastal is real and the beginning of a trend (GFS bias coming into play?) and not an aberration being thrown out by the 06Z GFS then I like our chances of seeing further shifts west of the coastal track, a little better intensification and a somewhat slower solution. 

As far as the upper level energy rotating through on Sunday. Haven't a clue. Models are all over the place with that feature and what it will probably come down to is what we see with the Friday coastal and its impact on the set up for Sunday.

That statement is the part I understand the least.  How does Friday impact Sunday?  That is something smarter people would know like Bob. 

[showmethesnow]

23 minutes ago, BristowWx said:

That statement is the part I understand the least.  How does Friday impact Sunday?  That is something smarter people would know like Bob. 

What happens with the coastal, stronger/weaker, west/east, quicker/slower, etc.. will have an impact upstream on the troughs configuration/tilt/placement etc... which in turn will also impact (dig, timing, etc...) of the energy rotating down within the trough to a certain degree. Another thing to look for is if the coastal will clear out the trough of low pressure left in its wake. If it does it probably would argue for strong upper level energy passing through the general region as it doesn't get dampened out. If we do see a trough of low pressure left behind we then look for where its placement will be. The upper level energy will weaken as it begins to transfer its energy towards a developing Miller B off the coast within the trough. So if that trough is far enough east we won't see the weakening of the upper level energy until it has moved through the region. Concurrently, if we see that trough far enough south and west we have the possibility of that upper level energy diving deep enough south where we see a Miller B form south enough to impact our area (Odds of this are slim). 

Really what it boils down to in my mind is the fact nothing about this setup Fri-Sun has been resolved whatsoever. But that is to be expected with so many moving parts involved.

[psuhoffman]

22 minutes ago, BristowWx said:

That statement is the part I understand the least.  How does Friday impact Sunday?  That is something smarter people would know like Bob. 

The atmosphere operates similarly to currents in a body of water.  What happens with one wave will impact things upstream (clogging up the flow and slowing things down for example) and possibly even downstream (kicking something along).  

[09-10 analogy]

7 hours ago, Bob Chill said:

we've got a full tank of gas, half a pack of cigarettes, it's dark out, and we're wearing sunglasses. 

It was around the time the Euro came out when the drugs began to take hold. 

[mappy]

im half in half out

[BristowWx]

2 minutes ago, mappy said:

im half in half out

that was the perfect post for that.  very nice. 

[Ralph Wiggum]

The atmosphere operates similarly to currents in a body of water.  What happens with one wave will impact things upstream (clogging up the flow and slowing things down for example) and possibly even downstream (kicking something along).  

We need at atmospheric earthquake and downstream tsunami in the Mid Atlantic/Northeast pronto!

[Scraff]

If anyone saw Judah Cohen’s blog last night, certainly interesting for sure. Thinks the way this winter lines up now is more akin to our 13/14 winter. Anyone have some time on their hands, here’s the link. http://www.aer.com/science-research/climate-weather/arctic-oscillation

[Cobalt]

6z GEFS still leads some hope

 

 

[BTRWx's Thanks Giving]

We still have a ways to go with the Friday/Saturday coastal.  It's too early to declare a trend towards the coast for certain, but recent looks could be a hint.  The strength of any low that may or may not form is a limiting factor I believe.  I have noticed the euro weakening the pressure values off the coast when precipitation forms, but there's still 3-4 days to correct one way or another! 

Here are the last 8 runs of the GFS.

 

[psuhoffman]

35 minutes ago, Cobalt said:

6z GEFS still leads some hope

 

 

Gefs has had a few runs like that only to back off next run. I will take it seriously if it holds or improves 12z. 

[Cobalt]

Wish I could dig up the runs from that 1st week in January before that storm. Same situation. Cold front came in, and during that and after the models ticked up NW

[BTRWx's Thanks Giving]

2 minutes ago, Cobalt said:

Wish I could dig up the runs from that 1st week in January before that storm. Same situation. Cold front came in, and during that and after the models ticked up NW

It doesn't always happen.  Every year the models seem to have different biased trends.  One year they will trend nw most of the time and others will trek out to sea as polar blocking trends increase.  I'm not quite sure yet for 17-18. 

[showmethesnow]

For those who were not sure what I was referring to when I mentioned blocking to the west of the track of the coastal. Or just generally wasn't sure what I was referring to when I said the upper levels looked better in my previous posts.

Now I will use the op runs because it gives you a much better idea of what I am referring to compared to the ensembles which are far less distinct due to their smoothing. I also want to mention that I am comparing this mornings run (06Z) to the 12Z run from yesterday due to the fact I think it is a much better representation of what we have been seeing the last couple of days on the models vs. the 00Z and probably the 18Z which I think were moving towards the 06Z solution. One other note. The time period is 6 hours off to represent the 6 hour slower development of the low on the 06Z thus giving a better representation of the upper levels when the storm is off of roughly OBX.

 

Yesterdays 12Z GFS at 102hrs'

Now below we have the southern jet (250 mb) which is basically the steering current for the weather at lower levels. This jet is represented by the pretty colors that are running up the coast. Now below it we see roughly where the track of a possible coastal will be which runs the southern edge of the jet. We also notice that the jet is almost straight as an arrow thus there is little to no backing of the flow. So what we have is a track that is pretty far south, no backing of the flow which would allow some intensification of a developing low and a fast jet that would quickly take any low OTS. It really isn't a good look overall for our chances with the DC/Balt corridor. Now compare this to the next image.

 

This mornings 06Z GFS run at 102 hours.

This look is a marked improvement from the previous one. We are now seeing some bowing of the jet which is indicative of a backing of the flow. What this backing of the flow does is give the low better ability to intensify, and slows down the storm to a degree. We are also seeing the jet itself has shifted westward pulling the track of any possible low north and westward as well. And to get an idea of the shift northward just compare the colors of the jet between the two images. As I said marked improvement for possibly impacting our region.

 

Now the GEFS seems to be supporting this trend as well but it is much harder to see with the smoothing involved as well as what looks to be some timing issues involved with when that low forms. Could dig into the individual ensembles to get better clarity but not going to waste my time at this point. Now this trend may be nothing more then an aberration the last couple of runs or maybe we are seeing the GFS' s bias coming into play. The next few runs will be very telling and I would not be shocked to see we have a more distinct low closer to the coast. Nor would I be shocked to see this all go POOF. 

 

 

[ErinInTheSky]

The 16 day total snowfall from the GFS is a kick in the nads. I'm actually quite surprised to see it. This is the first run in a LONG series of runs now that have showed nada, after all the other runs have showed something.

 

Here's to hoping the 12z brings back some sort of flakes!

 

[ryanconway63]

12z NAM looks interesting.......I know its the NAM in long range but still.

[Bob Chill]

Good post @showmethesnow

Glad I didn't stay up for the euro. lol. 6z gfs/gefs is decidedly west of previous but like you and others, one run doesn't mean nearly as much as all of them. lol. FWIW- the nam is doing the same thing. Backing UL flow more inland as the wave approaches. 

The good thing is that we don't need much adjustment from any model. It needs to happen today or tomorrow. By thurs track will be mostly locked. 

Down the line will go through the same process as the southern wave. Uncertainly with track/evolution/strength until close to the game. I want everything to lock into favorable from 5 days out as much as the next guy but that's very unrealistic. Except for rare events like the 16 blizzard, all of our events go through this process right up to the short range. Sometimes even 12 hours out and things are still shifting. Revisiting old event threads is always a good way to be reminded that med-short range can be as volatile as the LR. The upcoming period will not be boring nor will it be easy on the nerves. 

[BristowWx]

3 minutes ago, ryanconway63 said:

12z NAM looks interesting.......I know its the NAM in long range but still.

It does but after you get kicked in the pills enough you know what to avoid.  The NAM is an angry mule waiting to do just that

[pasnownut]

7 minutes ago, BristowWx said:

It does but after you get kicked in the pills enough you know what to avoid.  The NAM is an angry mule waiting to do just that

pills.....lol

While your statement is surely valid, it is useable to look for trends, and as Showme and Bob just alluded to...it shows the backing of isobars, indicating a jog west of the qpf fields.  To my eyes, i'd like to see that vort up north slow down to keep this trend alive.  Otherwise a push OTS is likely.

Hoping for continuation of the trends, as we have about 36-48 hours left until the tick back SE starts.  This is just years of model watching trends....no scientific reasoning whatsoever.

Nut

[pasnownut]

From Don S in NY thread.  Really enjoy his reads...  hope you do as well

 

This morning, the preliminary value of the Arctic Oscillation (AO) was -0.748. All five days of December have been negative with an average value of -0.691. Looking back to last December, the first five days also started out weakly negative with an average value of -0.196. Given the consistent guidance, December 6 will mark where winter 2017-18 diverges from the path taken last winter when it comes to the Arctic Oscillation. Starting December 6, the remainder of December 2016 saw the AO stay positive, and generally strongly positive. December 2016 finished with a monthly average AO value of +1.786. Following that, 30/31 days in January also saw a positive AO. Overall, 80% of days during meteorological winter had positive AO values.

A very different outcome appears increasingly likely this winter. The development of extreme blocking in November and forecast redevelopment of strong blocking in December suggest that winter 2017-18 will feature a lot more blocking than last winter. Moreover, the forecast long-duration of the current round of blocking favors a blocky winter overall. So, a colder and snowier winter than 2016-17 appears likely.

Through yesterday, NYC's December mean temperature was 45.3°. That is more than 3° above normal, but well below the monthly average of 50.8°, which was established in 2015. The coming regime change courtesy of an extended period of EPO-AO-PNA blocking will lead to negative monthly departures. December also has an increasing probability of above to possibly much above normal snowfall. A weak system could graze parts of the region late Friday into Saturday, bringing light accumulations to parts of the area. More light snow or flurries are possible on Sunday. A more meaningful storm could occur around the middle of next week (a feature that has periodically shown up on various runs of the computer models).

Overall, things remain on track for a colder and snowier than normal December. We are now near the point where the transition will take place.

 

 

 

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[CAPE]

12z GFS is literally a big (not yuge) run. Some subtle good signs, but time is a runnin' short.

[mitchnick]

23 minutes ago, Bob Chill said:

Good post @showmethesnow

Glad I didn't stay up for the euro. lol. 6z gfs/gefs is decidedly west of previous but like you and others, one run doesn't mean nearly as much as all of them. lol. FWIW- the nam is doing the same thing. Backing UL flow more inland as the wave approaches. 

The good thing is that we don't need much adjustment from any model. It needs to happen today or tomorrow. By thurs track will be mostly locked. 

Down the line will go through the same process as the southern wave. Uncertainly with track/evolution/strength until close to the game. I want everything to lock into favorable from 5 days out as much as the next guy but that's very unrealistic. Except for rare events like the 16 blizzard, all of our events go through this process right up to the short range. Sometimes even 12 hours out and things are still shifting. Revisiting old event threads is always a good way to be reminded that med-short range can be as volatile as the LR. The upcoming period will not be boring nor will it be easy on the nerves. 

And for reminding some that bad habits on model reading die hard.

[yoda]

Still a large amount of h5 energy at hr 84 on 12z NAM down in the south... looks like a very potent s/w