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The return of winter pattern disco


Damage In Tolland

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Boy what a difference 50 miles of latidude would make..lol. This is probably going to take until the final 36-48 hrs to figure out. I think the concern is that low pressure won't get its act together until it reaches the GOM, but we have almost 6 days to iron things out.

What a solution for Maine.

I will take 3-6" right now if i could get it guaranteed some how.......

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Comparing the 12z gfs and 00z euro, you see why ensembles are the way to go right now.

The gfs takes the incoming Pacific energy that hits the coast of BC, and moves it to the southeast...ahead of the PV that is located sw of Hudson Bay at hr 96. The 00z euro takes this energy and sort of phases this with a big vortlobe that rotates west from Hudson Bay, at hr 126. It's also a little slower too.

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I'm not sure what to make of these twin streams of vorticity as well. That seems a little suspect to me.

you know, it just more than seems to me that the GFS does not like to phase vorticity fields beyond 48-72 hours. Look at the last big bomb for example: remember how it had like 4 or 5 vorticity maxima mangled in the trough and could not close off a cohesive center for like 3 runs? It was actually phasing more successfully at day 10 prior to confusing things in the middle range of all things.

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In the last event, the ensembles did much better than the flip flopping op runs...during all those runs where it was too far east, the ensembles kept a track near the benchmark...while that ended up being wrong too, it was less wrong than the OP runs, so they scored better. You always have to take a probabilistic approach to these things at 5-6 days out.

Exceptionally good point! ...People have approached me in PM's before mystified why sometimes we make a call 2 weeks in advance and it seems to work out - ding ding ding.

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In the last event, the ensembles did much better than the flip flopping op runs...during all those runs where it was too far east, the ensembles kept a track near the benchmark...while that ended up being wrong too, it was less wrong than the OP runs, so they scored better. You always have to take a probabilistic approach to these things at 5-6 days out.

At this point a region wide 3-6"/4-8" event would be welcomed and if pans out that its more then it will be a bonus, Trying to get the timing for a bomb as we all know does not work out very well or we would have HECS type storms more often........

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This seems to be hit on pretty well by most of the models, A lot of arctic air in canada, Thats a good sign for down the road.......

That will be a nice source to have, esp for my area. If we indeed see troughing shift towards the Plains, then storms are going to want to make a run towards the northeast. Having the cold and a big high branching in from the west will help my area out.

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I am honestly not worried about the helter skelter (if I said that correctly) nature of the medium range models at this time. Last few coastal storms have shown a strong resilency to do what the medium range models said in the opposite form. FWIW models in this range tend to have a few strong biases:

1.) They tend to often speed up the southern stream to the point where the northern jet crushes the S/W to the south and east and then out to sea, missing the phase connection with the northern jet stream disturbance. They tend to shear the disturbance way out ahead of the northern jet. Then within 48 hours or so the real short range, the models bring back the phasing potential, given what we monitor on the water vapor imagery, this would be quite obvious.

2.) The models tend to slow down the northern jet stream energies too much, to where the timing of the phasing is off between streams and therefore there is no appreciable digging, and when there is digging the southern stream vort max is already way out to sea towards Bermuda. Models tend to correct themselves as the energy gets closer to better sampling. The fact that the main energy involved comes directly from the polar vortex, I think the models are already mishandling it to a degree. Only in the near term the models see what we observe on water vapor imagery as a stronger and faster disturbance ripping southward within the polar jet stream. Then the models obviously bring back the large storm.

Now given these biases in the medium range, yes even the EURO deals with these issues, one would think that the medium ground would be in nature to phase both jet streams into an overall mean upper level trough over the eastern US. I think this will be what will end up happening in the overall grand scheme of things as we get to within 48 hours of the potential event. One only has to monitor what happens mid week this week with the potential clipper system to bring in light snow in western SNE and light rain in eastern SNE. As well as see what the latest 12z NAM/GFS runs have done to bring alive the talks of the frontal wave precip and developing quicker than anticipated just 12 hours ago.

While I am saying I think caution is the best route, there is no doubt in my mind, that a major snowstorm has the potential to develop south of New England sometime next THursday through Saturday. Given the appreciable agreement in the overall individual GEFS ensemble members I think it is clear a storm will occur, the question is, is it with the southern stream phase or is the northern stream on its own.

We're pulling for the CCPSUSuperstorm2010 send off storm!:weight_lift:

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My take on this is that it's a clipper (or a mauler) and people should expect their several inches in clipper-like fashion and not even be seriously contemplating a so called SECS, MECS etc.... Unless and until the models forecast such a thing inside about 60 hours.

I think all that energy holding back in the southwest is a player also. It means a downstream ridge in the southeast. It may impinge on the ability of this northern stream system to dig enough and start favoring more of a central/northern NY/NE snowfall max.

The bigger deal for the east could be several days later if the SW energy ejects....

els

Comparing the 12z gfs and 00z euro, you see why ensembles are the way to go right now.

The gfs takes the incoming Pacific energy that hits the coast of BC, and moves it to the southeast...ahead of the PV that is located sw of Hudson Bay at hr 96. The 00z euro takes this energy and sort of phases this with a big vortlobe that rotates west from Hudson Bay, at hr 126. It's also a little slower too.

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Interesting...Not hard to see why some of the guidance have been emphasizing the -EPO orientation to the flow out in time. There is a very impressive 10mb thermal dipole in the stratospheric altitudes amid and over 60N and above latitudes. The warm region in the 10mb level initialized over northern Asia as of the 00z runs last night - the GFS mean is rotating this around Siberia and toward the EPO region. Meanwhile, the 100mb level - nearing the tropopause, initialized warm in Asia and the EPO region already... The superposition of the 10mb warm approach over the on-going warm annular ring nodes at 100mb out in time should put a very downward exertion on the atmosphere in that region, and so the onset of strong -EPO structure is highly favored.

Also the CPC AO calculation drills the AO down off the charts in the extended. There are so many cold signals in play over the next month one has difficulty quantifying what it may mean. But sufficed it is to say, colder than normal would be highly favored outside of typical large scale warm compensating regions around the northern hemisphere. Seeing arctic outbreaks on extended runs regardless of pattern idiosyncrasy amid the models can't be discounted.

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Looks like the ensembles develop a low near the BM, but then move it east. There must be some pretty big spreads, because an inv trough cuts right down the Pike, and also the fact there seems to be some spacing in the isobars, to the west of the low.

Yeah that is only more headaches...the spread definitely looked like it increased on the ensembles rather than decreased. GGEM looks like it doesn't dig the PV enough for us and only gives us a light 1-2" between 132-144...which I think is our biggest fear in not getting much out of this...the PV digging.

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Interesting...Not hard to see why some of the guidance have been emphasizing the -EPO orientation to the flow out in time. There is a very impressive 10mb thermal dipole in the stratospheric altitudes amid and over 60N and above latitudes. The warm region in the 10mb level initialized over northern Asia as of the 00z runs last night - the GFS mean is rotating this around Siberia and toward the EPO region. Meanwhile, the 100mb level - nearing the tropopause, initialized warm in Asia and the EPO region already... The superposition of the 10mb warm approach over the on-going warm annular ring nodes at 100mb out in time should put a very downward exertion on the atmosphere in that region, and so the onset of strong -EPO structure is highly favored.

Also the CPC AO calculation drills the AO down off the charts in the extended. There are so many cold signals in play over the next month one has difficulty quantifying what it may mean. But sufficed it is to say, colder than normal would be highly favored outside of typical large scale warm compensating regions around the northern hemisphere. Seeing arctic outbreaks on extended runs regardless of pattern idiosyncrasy amid the models can't be discounted.

Great post. Many a well thought out long range forecast made with month lead time is going into the toity this month it would seem.

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My take on this is that it's a clipper (or a mauler) and people should expect their several inches in clipper-like fashion and not even be seriously contemplating a so called SECS, MECS etc.... Unless and until the models forecast such a thing inside about 60 hours.

I think all that energy holding back in the southwest is a player also. It means a downstream ridge in the southeast. It may impinge on the ability of this northern stream system to dig enough and start favoring more of a central/northern NY/NE snowfall max.

The bigger deal for the east could be several days later if the SW energy ejects....

els

Yeah I notice this as well, funny you mention that.

It really is a matter of like 50 miles for this to be a big deal for I-90 in sne. Even with the inv trough like feature...it makes me think that some moisture rotating south from Maine is possible..given the mid level setup. Pretty complicated setup and potentially frustrating because it has a "feast" or "famine" appeal to it right now. I'm not expecting anything significant at this juncture, but of course we have to mention the obligatory "we're 6 days out." I'll just be happy for snow.

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Like what...snow? Because that's the predominant cover right now...

Okay--any non snowy surface: roads, walkways, etc. I'd also be concerned re: p-type, though I see the RUC says snow. I'll enjoy whatever it is from the sidelines; this will be an eastern special I think.

My take on this is that it's a clipper (or a mauler) and people should expect their several inches in clipper-like fashion and not even be seriously contemplating a so called SECS, MECS etc.... Unless and until the models forecast such a thing inside about 60 hours.

I think all that energy holding back in the southwest is a player also. It means a downstream ridge in the southeast. It may impinge on the ability of this northern stream system to dig enough and start favoring more of a central/northern NY/NE snowfall max.

The bigger deal for the east could be several days later if the SW energy ejects...

I'll take that in an instant.

No CAA at the surface. 44.5/38 attm.

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