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December 2019 Med/Long Range Disco


Bob Chill
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@frd  Things definitely look to be shifting around.  The stagnant +heights and +temp anoms at 50mb over N Canada looks to get shoved east.  I really have no idea what to expect but check this out...certainly fantasy range but the FV3 has been hinting at a new warming at the end of the run.  Looks to originate in Northern Africa...same place this current warming started.  Wait and see if it has legs.

3Ro0MUr.png

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1 hour ago, frd said:

I am not sure the outcome,  but this will in some form be a player,  whether though elongation of the vortex, displacement, etc. As we near hour mark 360 in fantasy land you can see the configuration may be a conducive one. This is also what HM mentioned two days ago, and it is still in the forecast currently moving forward.     

 

 

It makes more sense for the initiating ridge breaking to be on this side considering the much larger area of ocean relative to land.

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2 hours ago, poolz1 said:

@frd  Things definitely look to be shifting around.  The stagnant +heights and +temp anoms at 50mb over N Canada looks to get shoved east.  I really have no idea what to expect but check this out...certainly fantasy range but the FV3 has been hinting at a new warming at the end of the run.  Looks to originate in Northern Africa...same place this current warming started.  Wait and see if it has legs.

3Ro0MUr.png

 

Don S seems to think the talk about this potential split is  talked about incorrectly by some on social media.  

I assume based on his post that he does not agree with  BAMMWX, since they only focused on 50 mb. 

He also mentions a continuation of a +AO regime by the GEFS. . 

I bring you his post over from 33.  

 

from Don:

<<

Bad information about an imminent polar vortex split is circulating on Social Media. Even at the 50 mb level there is no split. Further, a true split happens at more than a single layer of the stratosphere. Not surprisingly, the GEFS forecasts the continuation of a general AO+ regime.

gfs_z50_nh_f240.png

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28 minutes ago, NorthArlington101 said:

The GEFS is 100% out on the anafrontal chance.

Couple members look okay for Friday. Not a single flush hit in the mix. Based on the weird snow map depiction I'd wager that a lot of the storms shown on the GEFS are mix-y.

Whats the snow mean for next weekend? The LP plots and the qpf signature look nice. Im assuming alot of 36 and rain?

gfs-ememb_lowlocs_us_30-1.png

gfs-ens_apcpn24_us_27-1.png

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The stark differences at H5 on the Euro and GFS just show how volatile this pattern is. So many shortwaves to key on, both in the southern and northern stream. It's going to be a pattern where answers will not be made until inside 4 days, and even then there could be some sharp shifts up to lead time. GFS is more amped in the northern stream for Tuesday/Wednesday with a progressive southern wave traversing the southern plains into the Mississippi Valley. A trailing shortwave over the Inter-mountain west dives south and phases on the backside of the southern disturbance and gains a neutral tilt over the Tenn Valley. Regional difluence on the leading edge of the trough provides a good signature for enhanced lift over the southern Mid-Atlantic, bringing a solid moisture field into a cold antecedent airmass with 1040+ surface high over northern New England. Those are the GFS details parsing with some winter precip in the mix.

Now for the Euro, it's a short and sweet reason of why it fails. Sheared northern stream energy coupled with southern wave closing off and drifting into the Bay of Campeche. No phasing streams, progressive flow, and lead southern shortwave early in the week is the main feature the Euro keys on for precip development next weekend. It's a completely different look and both solutions could have merit in the setup. 

Wednesday is tight. The models did bring in the front quicker yesterday compared to previous days, but now we're seeing the depth of the cold push, in latitude, being pushed back, which might hinder the prospects for snowfall, unless we get an energetic trailing piece along the boundary. Models have diverged away from that for the time being, so you're seeing a flat look with cold chasing precip. That's not historically how the area scores, but it's not impossible. Need to see models comeback to a more aggressive cold push imo. That way we can see a sharpening baroclinic ribbon and better chance for frozen to the NW side of the boundary.   

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2 hours ago, frd said:

 

Don S seems to think the talk about this potential split is  talked about incorrectly by some on social media.  

I assume based on his post that he does not agree with  BAMMWX, since they only focused on 50 mb. 

He also mentions a continuation of a +AO regime by the GEFS. . 

I bring you his post over from 33.  

 

from Don:

<<

Bad information about an imminent polar vortex split is circulating on Social Media. Even at the 50 mb level there is no split. Further, a true split happens at more than a single layer of the stratosphere. Not surprisingly, the GEFS forecasts the continuation of a general AO+ regime.

gfs_z50_nh_f240.png

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AO looks pretty neutral to me in the LR on the ensembles. Maybe slightly +, but trending less positive than it is in the short term. Seeing some hints here and there of heights building in the HL region as well, but who knows how it all shakes out at this point. One thing I like is, regardless of what models seem to advertise at h5, ground truth reality at verification is we are pretty consistently staying seasonably cold. That's a good thing IMO.

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

One thing I like is, regardless of what models seem to advertise at h5. ground truth reality at verification is we are consistently staying seasonably cold. That's a good thing IMO.

I guess,  but one never knows. 

Just because we were lucky so far does not mean it will last.  I agree we have more than often verified seasonal to cold and avoided a torch period, so far.

I however, can not shake Isotherm's view and a couple in his clan regarding tropical forcing/glamm/MT /AAM/ a stubborn PV, an ineffective QBO, etc. 

If correct, ( Tom ) we end this month warm and start Jan warm as well, with likely little snow.  Yeah, Ok, it is December but if his view is correct it will take weeks to get to a better pattern. The -EPO not looking as good, AO and NAO not looking good, etc.

Again two camps, seasonal December maybe  a little below normal , and the other whom if correct with their insights, we warm as the HL turn to crud and we run the warm MJO phases or simply  stagnant in the warm phase(s) along with possible consequences from the standing wave yet again. 

 

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Why worry about it? These predictions beyond 3-4 weeks are barely better than coin flips. The first two weeks of December were supposed to be warm we were told in November. So far, it's been mostly overcast and chilly/windy around these parts, very typical December weather. And warm/wet followed by cold/dry is a cycle we get here every single winter several times.

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14 minutes ago, Ji said:

we are amazing at missing snow. All the cold air around on the 18z gfs and we get nothing

No snow? Looks like you would be in the 1-2 inch region.

snow.gif.b960edd01dd85f78496cc1ad9b132174.gif

 

Which brings us to this comment. Couldn't wait a full 3 days before you put the lie to this statement. :lol:

On 12/4/2019 at 7:04 PM, Ji said:

lol i have totally different desires in December and they are very low...just enough snow/ice to cover the grass and snow on the christmas lights with cardinals flying and stuff. So yea..1-3 would be great....just want a brief live hallmark movie scene

 

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