December 2019 Med/Long Range Disco

[CAPE]

Just now, NorthArlington101 said:

 

18z is out now.

 

I always forget about that lol. Oh well. Off run! 

[Chris78]

Icon gives the area around .5 qpf from the ULL. Its just a tad to warm. Mid 30's to around 40 for most. 

[midatlanticweather]

Nam still icing n&w of the city pretty well. Still overdone and Temps way too marginal with the precip rates

[Cobalt]

UKIE close to something for extreme N parts of our subforum 

[showmethesnow]

No surprises on the overnight runs. Still looking rough on the front end with our best chances with the UL low rotating through. Couple of things may help our chances as far as the front end though. Timing, which occurs in the late night/early morning hours and the fact that quite often the precip will come in several hours earlier then forecasted potentially catching the cold before it escapes. At this point best case scenario in my mind is the possibility of a slushy coating around the PA line with others seeing some snowflakes/pingers in the air at the onset. Still looking at roughly 48 hours so let's see what the temp profile of the atmosphere looks like inside of 24 when we get inside the mesos' wheelhouse. 

As far as the UL low the pass it makes through the region is a good one. There are a couple of things in play here. We should have instability precip popping up within the core of the  UL low which chances are good the models are under playing at this time. The UL pass argues that DC and south through northern and central VA are in the prime spot for this. Then we are also looking at the possibility of wrap around precip as we see interaction between the UL low and the departing surface low. This wrap around will favor the NW sector of the UL low as it moves through the region. Knowing this we are probably seeing most of MD in play with those north and east in a more favorable locale. Now the one big issue we are facing at this time is that the surface cold is lagging behind somewhat from the levels above it. So though we are seeing sufficient cold at 850 mbs and above what we are seeing at 900 mbs and below aren't with the surface quite toasty. With such a deep layer of warmth and the surface temps quite warm (seeing upper 30's-low 40's through DC/Balt corridor) seeing snow will be highly rate dependent. Now taking all of this in consideration best case scenario is probably spotty snow showers in the heavier convective cells within the UL low as well the potential for a band of snow within the wraparound where the heavier rates are occurring. A slushy coating or even an inch or two, though I may be stretching that, could occur within the wrap around band that potentially sets up (favoring those to the north and east of course).

[Eskimo Joe]

The complete lack of a good cP air mass in the long range across all guidance is concerning.

[frd]

36 minutes ago, Eskimo Joe said:

The complete lack of a good cP air mass in the long range across all guidance is concerning.

The much anticipated warm December is coming. Simply can not fight the deep tropics. 

The same concerns last year regarding the MJO that lasted in the warm phases for weeks on end may repeat again this December.

The latest AO forecast do not look as good today, the NAO going up.  Source regions are warming. The camp that predicted an overall warm December is a step closer to possibly being correct. Early December this year similar to last year, and then we warm.  Whether it lasts two weeks or longer is still hard to pin down. 

The consistency of the last few years of the pronounced warm up post 12/20 is an increasing risk again this December. 

There is a repeating pattern of late.... warm Octobers , cold Novembers, Decembers turning  warmer after the first week.    There could be a delay this December with the cold winning out until the 10th, but still looking like we warm once past the 10th.  

I will  also mention new research reinforces that the idea in which the MJO is spending more time in the warmer phases while racing  through the cold phases. This is pronounced in the time period from 2010 forward.

 

  

[dallen7908]

3 minutes ago, frd said:

The much anticipated warm December is coming. Simply can not fight the deep tropics. 

The same concerns last year regarding the MJO that lasted in the warm phases for weeks on end may repeat again this December.

The latest AO forecast do not look as good today, the NAO going up.  Source regions are warming. The camp that predicted an overall warm December is a step closer to possibly being correct. Early December this year similar to last year, and then we warm.  Whether it lasts two weeks or longer is still hard to pin down. 

The consistency of the last few years of the pronounced warm up post 12/20 is an increasing risk again this December. 

There is a repeating pattern of late.... warm Octobers , cold Novembers, Decembers turning  warmer after the first week.    There could be a delay this December with the cold winning out until the 10th, but still looking like we warm once past the 10th.  

I will  also mention new research reinforces that the idea in which the MJO is spending more time in the warmer phases while racing  through the cold phases. This is pronounced in the time period from 2010 forward.

 

  

Yes the ensembles hint that the AO may head positive again after sinking to neutral in the mid-range but that is in the hard to forecast 10-15 day the frame. 

Is the repeating pattern statistically significant?

Please provide a reference for the new research on MJO cycling. 

 

 

[CAPE]

1 hour ago, Eskimo Joe said:

The complete lack of a good cP air mass in the long range across all guidance is concerning.

Not sure I would characterize it as concerning. We are talking about early-mid Dec in the MA. Looks like mostly seasonal temps.

[CAPE]

12z NAM at range.

 

[frd]

Just now, dallen7908 said:

Yes the ensembles hint that the AO may head positive again after sinking to neutral in the mid-range but that is in the hard to forecast 10-15 day the frame. 

Is the repeating pattern statistically significant?

Please provide a reference for the new research on MJO cycling. 

 

 

I brought it up because it has been repeating lately  in some form or fashion (  a 2010's weather theme, and you can read more about MJO study here )

https://www.nature.com/articles/s41586-019-1764-4

 

and this from @bluewave

Yes, I just posted that in the climate change forum with all the charts included. The changes to the MJO have become a big part of our 2010’s weather patterns. It shows what we already figured out. The MJO has been spending more time in the Maritime Continent phases due to the rapid SST warming of the Indio-Pacific warm pool.

 

 

[Bob Chill]

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

Not sure I would characterize it as concerning. We are talking about early-mid Dec in the MA. Looks like mostly seasonal temps.

Agree. Concerning is when we're staring down the barrel of a toaster bath pattern. I'm not seeing that. Quite rare to stay below normal temp wise when the AO flips positive and that's pretty much a lock. Pattern doesn't look worse than 1 step away from something workable though. Much better than needing 2-3 weeks and like 4 steps to get into the goods. 

If NA turns into a giant bubble of warm pac air I'll get concerned. 

[showmethesnow]

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

Not sure I would characterize it as concerning. We are talking about early-mid Dec in the MA. Looks like mostly seasonal temps.

Not particularly concerned myself. Temps aren't exactly scorching in our source region (marginally above) and we are entering the time of year where we don't need Canada under deep blue and purples with neg anomalies. Also considering that the models have been erratic in the longer ranges when it does come to what we are seeing over the pole in regards to the pv I think it is anything but a slam dunk that the models have things nailed down.

[midatlanticweather]

Just now, Bob Chill said:

Wgree. Concerning is when we're staring down the barrel of a toaster bath pattern. I'm not seeing that. Quite rare to stay below normal temp wise when the AO flips positive and that's pretty much a lock. Pattern doesn't look worse than 1 step away from something workable though. Much better than needing 2-3 weeks and like 4 steps to get into the goods. 

If NA turns into a giant bubble of warm pac air I'll get concerned. 

You know how to put things in a way that is very clear Bob! LOL! I still think the Pacific is more friendly this year.. as long as the AO can be neutral to favorable, we will get our chances. In a way, the relatively "close call" this weekend is yet another encouraging sign. Just need that zone to set up further south and get a bit colder for some fun. This is normal for a transition month. November has been a bonus as a cold month, and we want that to stick around.. but it just has not been the case so many years.. December is always a bonus month.. we get snow, we are happy and it adds to the season, but we can get past December and still do well. I do want some snow though! (don't we all) - I am always captain obvious. I am not alarmed and I am still optimistic we score something in December! Late December at this point. I am happy to be wrong and get it sooner though!

 

 

[CAPE]

2 minutes ago, Bob Chill said:

Agree. Concerning is when we're staring down the barrel of a toaster bath pattern. I'm not seeing that. Quite rare to stay below normal temp wise when the AO flips positive and that's pretty much a lock. Pattern doesn't look worse than 1 step away from something workable though. Much better than needing 2-3 weeks and like 4 steps to get into the goods. 

If NA turns into a giant bubble of warm pac air I'll get concerned. 

Exactly. It's a decent enough look to think it can become more favorable going forward. I am pretty happy just seeing the lack of SE ridging on the means, lol.

[showmethesnow]

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

12z NAM at range.

 

Mesos are definitely icier then the globals. But we have been burned too many times outside of 48 hours, if not even 24 hours, on temps especially when the globals don't agree. The money runs will be tonights and especially tomorrows 12z where I am sort of expecting that they will fall more in line with the globals.. 

[CAPE]

Just now, showmethesnow said:

Mesos are definitely icier then the globals. But we have been burned too many times outside of 48 hours, if not even 24 hours, on temps especially when the globals don't agree. The money runs will be tonights and especially tomorrows 12z where I am sort of expecting that they will fall more in line with the globals.. 

I was referring to the ULL pass and the heavy snow it develops lol. Way outside of its wheelhouse though.

[showmethesnow]

Just now, C.A.P.E. said:

I was referring to the ULL pass and the heavy snow it develops lol. Way outside of its wheelhouse though.

Yeah, I saw that as well. UL low captures the surface off the northern Jersey coast. One of the better scenarios. But as you said. Wheelhouse. Outside of.

[CAPE]

Just now, showmethesnow said:

Yeah, I saw that as well. UL low captures the surface off the northern Jersey coast. One of the better scenarios. But as you said. Wheelhouse. Outside of.

Still to be determined how that part evolves. My guess is the UL develops its own area of precip but does not capture the coastal low, so the good deform precip ends up just to the NE, and then there could be a dead zone in between where only light precip falls (my yard).

[WEATHER53]

1 hour ago, frd said:

The much anticipated warm December is coming. Simply can not fight the deep tropics. 

The same concerns last year regarding the MJO that lasted in the warm phases for weeks on end may repeat again this December.

The latest AO forecast do not look as good today, the NAO going up.  Source regions are warming. The camp that predicted an overall warm December is a step closer to possibly being correct. Early December this year similar to last year, and then we warm.  Whether it lasts two weeks or longer is still hard to pin down. 

The consistency of the last few years of the pronounced warm up post 12/20 is an increasing risk again this December. 

There is a repeating pattern of late.... warm Octobers , cold Novembers, Decembers turning  warmer after the first week.    There could be a delay this December with the cold winning out until the 10th, but still looking like we warm once past the 10th.  

I will  also mention new research reinforces that the idea in which the MJO is spending more time in the warmer phases while racing  through the cold phases. This is pronounced in the time period from 2010 forward.

 

  

This is mostly bogus and no determination or patten can be determined from 2010 forward 

[frd]

10 minutes ago, WEATHER53 said:

This is mostly bogus and no determination or patten can be determined from 2010 forward 

Sorry, nothing is bogus here.

Research is convincing that during this decade there has been impressive warming in the Indo-Pacific warm pool and changes in the behavior of the MJO. Since 2010 there has been a tendency for repetitive Fall patterns.  

If you don't agree with the data that is fine. 

 

   

[WEATHER53]

8 minutes ago, frd said:

Sorry, nothing is bogus here.

Research is convincing that during this decade there has been impressive warming in the Indo-Pacific warm pool and changes in the behavior of the MJO. Since 2010 there has been a tendency for repetitive Fall patterns.  

If you don't agree with the data that is fine. 

 

   

8 years of observations is  not confirming “data”

everyday a new index is thrown out.  I think I will just take a 250X250 square mile northeast of Bermuda and scribble out some brand new index correlation to winter weather in the mid Atlantic.

Some of it is science with a proven background but mostly not.

 

[frd]

2 minutes ago, WEATHER53 said:

8 years of observations is  not confirming “data”

everyday a new index is thrown out.  I think I will just take a 250X250 square mile northeast of Bermuda and scribble out some brand new index correlation to winter weather in the mid Atlantic.

Some of it is science with a proven background but mostly not.

 

I understand your point. 

[psuhoffman]

1 hour ago, C.A.P.E. said:

I was referring to the ULL pass and the heavy snow it develops lol. Way outside of its wheelhouse though.

I certainly would use the NAM as confirmation but I do think the ULL qpf is being underdone by the guidance. 

[psuhoffman]

57 minutes ago, WEATHER53 said:

This is mostly bogus and no determination or patten can be determined from 2010 forward 

Did you bother to read the study before deciding it’s trash?  

[psuhoffman]

2 hours ago, Bob Chill said:

Agree. Concerning is when we're staring down the barrel of a toaster bath pattern. I'm not seeing that. Quite rare to stay below normal temp wise when the AO flips positive and that's pretty much a lock. Pattern doesn't look worse than 1 step away from something workable though. Much better than needing 2-3 weeks and like 4 steps to get into the goods. 

If NA turns into a giant bubble of warm pac air I'll get concerned. 

I’m not concerned but will point out the smoothed our blah look on the ensembles day 10-15 is not because they mostly think that will be the pattern. It’s becagas they have no clue with huge divergence and a mean that combines a lot of variance (some good looks and some bad) into an ambiguous mean.  In short that look is not likely and it’s going to end up adjusting one way or the other and depending on which camp is correct we could end up with a pretty good pattern or a real crap one. 

[psuhoffman]

2 hours ago, frd said:

The much anticipated warm December is coming. Simply can not fight the deep tropics. 

The same concerns last year regarding the MJO that lasted in the warm phases for weeks on end may repeat again this December.

The latest AO forecast do not look as good today, the NAO going up.  Source regions are warming. The camp that predicted an overall warm December is a step closer to possibly being correct. Early December this year similar to last year, and then we warm.  Whether it lasts two weeks or longer is still hard to pin down. 

The consistency of the last few years of the pronounced warm up post 12/20 is an increasing risk again this December. 

There is a repeating pattern of late.... warm Octobers , cold Novembers, Decembers turning  warmer after the first week.    There could be a delay this December with the cold winning out until the 10th, but still looking like we warm once past the 10th.  

I will  also mention new research reinforces that the idea in which the MJO is spending more time in the warmer phases while racing  through the cold phases. This is pronounced in the time period from 2010 forward.

 

  

How do we know the mjo is actually going through the torch phases 3-7?  The last attempt was completely thwarted and guidance is ambiguous right now wrt if this next wave progresses. GEFS thinks it is but euro and CMC guidance suggests another aborted attempt.   I have very low confidence (even compared to normal) where we go past day 10  

[cbmclean]

4 minutes ago, psuhoffman said:

I’m not concerned but will point out the smoothed our blah look on the ensembles day 10-15 is not because they mostly think that will be the pattern. It’s becagas they have no clue with huge divergence and a mean that combines a lot of variance (some good looks and some bad) into an ambiguous mean.  In short that look is not likely and it’s going to end up adjusting one way or the other and depending on which camp is correct we could end up with a pretty good pattern or a real crap one. 

Curious why you are not concerned.  Someone posted an MJO forecast in the banter firm.  Patented entry into crap phases and sloooooooooow down.  Has me spooked.

Edit Nevermind.  You answered my question before I even posted it.

[WxUSAF]

MJO forecasts are never great. There’s a bias to kill waves off into the COD when in reality most propagate through. What’s happening now though is the +IOD has generated a strong standing wave in the West Indian Ocean (phase 8-1) that’s confusing the MJO forecasts. Combine that with the cooler than normal waters near the maritime continent means that the early MJO wave death predictions actually aren’t crazy. 

[yoda]

URGENT - WINTER WEATHER MESSAGE
National Weather Service Baltimore MD/Washington DC
245 PM EST Fri Nov 29 2019

MDZ501-502-WVZ050-051-055-501>504-300345-
/O.NEW.KLWX.WS.A.0007.191130T2300Z-191201T1700Z/
Extreme Western Allegany-Central and Eastern Allegany-Hampshire-
Morgan-Hardy-Western Grant-Eastern Grant-Western Mineral-
Eastern Mineral-
245 PM EST Fri Nov 29 2019

...WINTER STORM WATCH IN EFFECT FROM SATURDAY EVENING THROUGH
SUNDAY MORNING...

* WHAT...Significant icing possible with the potential for ice
  accumulations around one-quarter inch.

* WHERE... Portions of western Maryland and the Potomac Highlands
  in West Virginia.

* WHEN...From Saturday evening through Sunday morning. Freezing
  rain is most likely Saturday night.

* IMPACTS...Power outages and tree damage are possible due to the
  ice. Travel may be dangerous.