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November 2013 pattern and discussion


WxJordan

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GFS is really struggling with convective feedback problems. These images show only convective precipitation, so you can see how the models cumulus scheme is effecting things.

 

Notice at 150 the SLP pattern:

gfsSE_sfc_cprec_150.gif

 

Now notice how the low re-centers back to the southwest as another bullseye of convection develops.

gfsSE_sfc_cprec_156.gif

 

Finally, much of that batch of precip over the CLT region is also created from the GFS' cumulus scheme.

gfsSE_sfc_cprec_162.gif

 

Not saying this won't happen, but this normally signals problems with the model's depiction of things in my experience.

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GFS is really struggling with convective feedback problems. These images show only convective precipitation, so you can see how the models cumulus scheme is effecting things.

 

Notice at 150 the SLP pattern:

 

 

Now notice how the low re-centers back to the southwest as another bullseye of convection develops.

 

 

Finally, much of that batch of precip over the CLT region is also created from the GFS' cumulus scheme.

 

 

Not saying this won't happen, but this normally signals problems with the model's depiction of things in my experience.

 

Thanks for the info. Let's just bask in the first GoFuS fantasy of winter  :tomato:

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I will add that much of the convective elements of precip are associated with the approach of the H5 low (and of course the steepening lapse rates that come with it), and the fact it remains stronger/closed off. So while it may not be entirely inaccurate, it is possibly overdone. If the H5 can remain this intense then maybe the cold pool associated with it could be enough to force a changeover, yet another twist to watch for.

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Huge model issues for next Wednesday into Thursday on the GFS. This is why you need to use them carefully. If you just looked at the snow panel you'd think tons of snow, but looking at the surface temperatures, soundings and other upper air parameters the snow doesn't make sense. I think the GFS is struggling big time with this solution. 

 

Brad Panovich WCNC not buying it no support from the ensembles or even the GFS soundings. Looks like model errors in snow totals.

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I choose to believe it as both conceivable and probable.  Let us not discuss of it anymore. 

 

It's a completely dynamically driven snow output.  If you look at the sounding you can see how complex it is with the deepening closed UL and the HP closing in.

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Huge model issues for next Wednesday into Thursday on the GFS. This is why you need to use them carefully. If you just looked at the snow panel you'd think tons of snow, but looking at the surface temperatures, soundings and other upper air parameters the snow doesn't make sense. I think the GFS is struggling big time with this solution. 

 

Brad Panovich WCNC not buying it no support from the ensembles or even the GFS soundings. Looks like model errors in snow totals.

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What?  Just because there's a narrow strip of heavy snow right around Charlotte, with no other totals around it to the south OR north??  What's weird about that?  Charlotte is due.  That's all we need to know. 

 

:)

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That track of that low Wed. is getting better.  Need to train them early to go across Fla. and not up into Ga.  Those gulf lows carry too much heat.  Want the northern fringe moisture, but not the Waa.  Stay, good boy, stay in Fla. Tony and Shack want sleet!!!  And CandyMan needs a 6 inch sleeter to add to his resume, lol. T

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Something to think about is the amount of dry air that is going to be in place before next weeks system. (per 12z GFS):

At hour 126 dew points will be in the mid-upper teens around Raleigh

At hour 132 dew points jump to near 30

At hour 138 dew points jump to the mid-upper 30s (with precip falling)

At hour 144 dew points jump to the low 40s

 

Very possible, but many times the models do not handel the cold/dry air very well and will scour it out too fast. If we can get any kind of CAD to setup I think a short period of freezing precip will be possible.

 

Hybrid cold air damming events can also lead to the development of winter weather over the Carolina piedmont if temperatures are cold enough. In-situ cold air damming events can have periods of short-lived winter weather. However, because there is no direct connection to a source region of cold air, in-situ damming often scours more rapidly.

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Nice step. All we needed was the system to slow down and this shows just that.

 

I hardly think that is all we needed, Brick.

 

 

Huge model issues for next Wednesday into Thursday on the GFS. This is why you need to use them carefully. If you just looked at the snow panel you'd think tons of snow, but looking at the surface temperatures, soundings and other upper air parameters the snow doesn't make sense. I think the GFS is struggling big time with this solution. 

 

Brad Panovich WCNC not buying it no support from the ensembles or even the GFS soundings. Looks like model errors in snow totals.

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We can always count on Brad to keep us grounded in reality.  This system continues to be interesting to watch, but I am choosing to temper my enthusiasm until we get much closer to the actual time frame.  Only 24+ more runs of the GFS left until Go Time!!

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I will add that much of the convective elements of precip are associated with the approach of the H5 low (and of course the steepening lapse rates that come with it), and the fact it remains stronger/closed off. So while it may not be entirely inaccurate, it is possibly overdone. If the H5 can remain this intense then maybe the cold pool associated with it could be enough to force a changeover, yet another twist to watch for.

Agree. Honestly the models may continue doing a piss poor job till about 24-36 hours out. But thats what is rattling my brain. Considering that nao and ao is forecasted to be near nuetral that doesn't give much diving power for the re enforcing shot of cold air to come in even with slight ridging out west. But given the general long wave scheme of things if this system remains strong and closed off wouldn't that allow the temps to drop on the western side(aloft) to allow for a quicker change over than what has and currently being modeled. Pretty much allow for more northern stream interaction.

 

This is a good sign - keep showing that block moving into the arctic. Hello -AO.

Aleutian low still holding strong.  Loving the pacific this season so far.

F1QYxMi.gif

 

Positive signs. Nice +pna -ao and -nao.

 

While I don't want to sound like negative nancy..... I sure hope the PV doesnt get that strong or stronger. With such a strong PV on our side no matter how much blocking or activity on the Stj it will not save us from a cold flat suppressed zonal flow with the storm track confined along the gulf coast states.

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T, D is banging the "the GFs is crap bcause the low doesnt come up he coaste sand it can't hand le easr corst winner sotmrs passed 84 houers monley crap" drum.

I haven't looked at any stats on the GFS's 84 hour + east coast winter storm progs, but isn't the issue around it over-doing the cold pressing south and thus squashing the system out to sea? In this case, we're dealing with a southern stream system that, I thought, when dealing with split flow systems of this type, usually exit the country near the same latitude they enter. Isn't that generally correct?

If so, and since we're not really dealing with a suppressing cold air mass, the track seems to make sense to me, especially given the fact that there's not much interaction with the northern stream. The other details, like snowfall, timing, dynamic cooling, etc, I could accept as fairly inaccurate at this point. But the general track and movement seem ok to me.

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Canadian model continues to leave the proverbial door open to something bigger if the timing of the cutoff slowed down a little more. Models still seem to be struggling just getting the H5 pattern modeled consistently. Until that happens, worrying about the mesoscale features seems futile.

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Agree. Honestly the models may continue doing a piss poor job till about 24-36 hours out. But thats what is rattling my brain. Considering that nao and ao is forecasted to be near nuetral that doesn't give much diving power for the re enforcing shot of cold air to come in even with slight ridging out west. But given the general long wave scheme of things if this system remains strong and closed off wouldn't that allow the temps to drop on the western side(aloft) to allow for a quicker change over than what has and currently being modeled. Pretty much allow for more northern stream interaction.

 

 

Positive signs. Nice +pna -ao and -nao.

 

While I don't want to sound like negative nancy..... I sure hope the PV doesnt get that strong or stronger. With such a strong PV on our side no matter how much blocking or activity on the Stj it will not save us from a cold flat suppressed zonal flow with the storm track confined along the gulf coast states.

 

That's an overrunning dream for us.  I wouldn't like it if I lived further north.

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