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Winter 2011-2012 Kickoff Thread | December 2011


earthlight

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Only 44 at LGA with full sunshine. Major bust on temps today.

Newark with a high of 46 today -- most forecasts were definitely a few degrees too high. I believe OKX had NYC at 49 though which isn't terrible.

That's a good sign as it means the cold shots coming in are stronger than progged (able to beat down the SE ridge), and once we get into the colder pattern later next week, we're liable to have several days with highs well below average.

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That's a good sign as it means the cold shots coming in are stronger than progged (able to beat down the SE ridge), and once we get into the colder pattern later next week, we're liable to have several days with highs well below average.

Meh, that just means SNE see's more snow and we see an extra 10 minutes of sleet.

SE ridge really could care less about that strength of the cold air, its been 20 degrees at 10pm and I have woken up at 34 before the precip even started, lol.

I see nothing at all right now to think we get much in the next three weeks and based on what John told me about the MJO forecasts our exepectations of an improved pattern around new years could be too early as well.

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Meh, that just means SNE see's more snow and we see an extra 10 minutes of sleet.

SE ridge really could care less about that strength of the cold air, its been 20 degrees at 10pm and I have woken up at 34 before the precip even started, lol.

I see nothing at all right now to think we get much in the next three weeks and based on what John told me about the MJO forecasts our exepectations of an improved pattern around new years could be too early as well.

We've seen plenty of times where it's been very cold one day and the next day it's raining. The cold shots coming into the US so far definitely appear to be strong; last December had sustained cold air, but the cold air wasn't very strong, -20c 850mb temps only briefly dropped twice in the month into the US, in the mid month storm and 12/31. Unlike last December though, the cold air is focused over the central US, and the brief cold that does come in only bends the ridge and is quickly pushed out without completely breaking the SE ridge. The time frame after at least 12/10 does appear to indicate a much more weakened SE ridge, when we should have better chances for cold and potentially a Northeast snowstorm, but the time frame for that doesn't appear to be too long with signs of a worse pattern returning. Although it's more of a worst case scenario, honestly it wouldn't surprise me if we have to wait until mid January for better sustained cold and snowstorm chances.

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That's a good sign as it means the cold shots coming in are stronger than progged (able to beat down the SE ridge), and once we get into the colder pattern later next week, we're liable to have several days with highs well below average.

We already have strong SE ridge, at least at 500mb. 850mb 0C line was over NY State by 14z, with surface temps <32F, in the Interior Northeast and Mid-Atlantic .If today means anything, it would be that there is a greater potential for sleet/freezing rain than a snow, from the colder pattern later next week:

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18z gefs continues to keep the day 5 storm weak and surpressed and as a result colder. Even for the coast.

A few days ago I was cautioning people to let the shortwave come on land for proper sampling as models might be over amplifying it and thus causing a long torch and a big time SE ridge.

It's clear now that the shortwave is weaker then progged and will not dig for days causing a massive SE ridge, like models had a couple days ago.

What seemed like a late next weekend cold front is now Wednesday to Thursday.

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18z gefs continues to keep the day 5 storm weak and surpressed and as a result colder. Even for the coast.

A few days ago I was cautioning people to let the shortwave come on land for proper sampling as models might be over amplifying it and thus causing a long torch and a big time SE ridge.

It's clear now that the shortwave is weaker then progged and will not dig for days causing a massive SE ridge, like models had a couple days ago.

What seemed like a late next weekend cold front is now Wednesday to Thursday.

Is the SW onshore yet?

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Meh, that just means SNE see's more snow and we see an extra 10 minutes of sleet.

SE ridge really could care less about that strength of the cold air, its been 20 degrees at 10pm and I have woken up at 34 before the precip even started, lol.

I see nothing at all right now to think we get much in the next three weeks and based on what John told me about the MJO forecasts our exepectations of an improved pattern around new years could be too early as well.

Well the pattern to me looks colder than normal overall the next couple weeks thanks to the -EPO pulse. As far as snowfall, the lack of blocking means we'll need to time pcpn events and cold highs almost perfectly to get decent snows on the coast. I can see a light event though, maybe a 1-3/2-4 type deal, in this pattern through the 20th.

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Well the pattern to me looks colder than normal overall the next couple weeks thanks to the -EPO pulse. As far as snowfall, the lack of blocking means we'll need to time pcpn events and cold highs almost perfectly to get decent snows on the coast. I can see a light event though, maybe a 1-3/2-4 type deal, in this pattern through the 20th.

I honestly would be very surprised if anybody in the metro area or immediate suburbs saw any accumulating snowfall before at least December 20th. The 18z GFS is also an awful solution as it tries to let a strong shortwave traverse the entire country without any blocking before it starts amplifying it when the surface low is off the coast. That's not happening. Not sure exactly how that specific shortwave will behave, but the GFS's depiction at 500mb is laughable.

Regardless...the MJO forecasts look pretty bad too with a big loop into the COD from Phase 4-5 around mid-month followed by a slow re-emergence out of it by around Christmas. This would bring us to Jan 1 with a re-emergence into Phase 6 and then a possible movement into Phases 7 and 8 thereafter. With the typical lag it could take until the first or second week of January to get the MJO support, which would line up well with the forecast break in the stratospheric freezer which we are currently in--which is helping to keep the Polar Vortex near Greenland and inhibit any high latitude blocking.

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One thing about shortwaves coming onshore and all of a sudden more accurate forecasts occur: Remember what happened to the Boxing Day blizzard?

That storm was unique in the fact that the shortwave which was mishandled was actually not the one everyone was watching. We all waited with anticipation for the shortwave to come onshore on the West Coast (the phasing s/w which was important), but the one that was mishandled was actually over a sparse data area in Canada. Once this feature came farther south towards better sampling, it was clear it was going to be more amplified.

I will never forget, two days before the storm there was one SREF member showing the system coming up the coast and hammering us all. I went back to the Midwest panels and looked at H5 and told two colleagues "this is what needs to happen to get this storm to come up the coast". That specific member (ETA-5) was taking the shortwave from Canada, surging it due south through ND/SD/NE/KS/OK, and eventually scooping up the shortwave near the Gulf. At the time no other model was remotely close to this--they were way farther east/southeast with that feature.

As it turned out, the trends began the next morning and the feature shifted west and the rest is history. But I always tell that ETA-5 story.

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Here's a great shot of what I was talking about. Look at the shortwave over the Plains. That's unbelievably far west considering the early model progs on this system, and even the progs a day or two before it. It may be hard to see, but imagine the swing motion that the shortwave was in at the time. It was literally about to scoop up and phase with the shortwave over the Gulf, and go on to create the beast that was Dec 26 2010.

RUC Analysis (what eventually happened)

http://i.imgur.com/gBDU4.gif

Here is the NAM 36 hour forecast on this peice of vorticity. I mean, really? It's not even on the map remotely close to where it ended up. Instead it's over Iowa moving southeast. This run eventually went out to sea (what a surprise), but it was THIS feature that the models were missing.

NAM 36 hrs (36 hr lead on this vort over Plains, probably about 60+ hrs for our storm itself)

http://i.imgur.com/7G3F0.gif

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That storm was unique in the fact that the shortwave which was mishandled was actually not the one everyone was watching. We all waited with anticipation for the shortwave to come onshore on the West Coast (the phasing s/w which was important), but the one that was mishandled was actually over a sparse data area in Canada. Once this feature came farther south towards better sampling, it was clear it was going to be more amplified.

I will never forget, two days before the storm there was one SREF member showing the system coming up the coast and hammering us all. I went back to the Midwest panels and looked at H5 and told two colleagues "this is what needs to happen to get this storm to come up the coast". That specific member (ETA-5) was taking the shortwave from Canada, surging it due south through ND/SD/NE/KS/OK, and eventually scooping up the shortwave near the Gulf. At the time no other model was remotely close to this--they were way farther east/southeast with that feature.

As it turned out, the trends began the next morning and the feature shifted west and the rest is history. But I always tell that ETA-5 story.

The trends with that storm definitely are ones to remember... luckily I still have the 850mb/surface pressure GFS/NAM/ECM/CMC performance for that storm and the days before saved. The CMC was by far the worst out of them, at hour 66 when the storm was at North Carolina's latitude it was almost south of Nova Scotia.

Although the late October storm wasn't nearly as bad as that one, the GFS did actually pop something up before the other models when it still appeared that there wouldn't be a Saturday storm. On its Sunday 10/23 18z run it popped up a weak offshore storm that appeared to have the potential to become something bigger. Although no other model showed any storm that close to the coast, the following day the models were showing a stronger storm affecting the East Coast.

post-1753-0-24828400-1322969948.jpg

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The 0z GFS once again seems to change its mind on the Thursday storm... at 12z Wednesday it now shows a less amplified solution that doesn't look like it's organizing into a big storm. Definitely a sign that the GFS isn't settling on a single solution yet, and its 6z run may show something different again.

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The 0z GFS once again seems to change its mind on the Thursday storm... at 12z Wednesday it now shows a less amplified solution that doesn't look like it's organizing into a big storm. Definitely a sign that the GFS isn't settling on a single solution yet, and its 6z run may show something different again.

Looks pretty potent to me at 102. The front has cleared the coast by then.

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0z GFS shunts this storm to our south and east.

Complete turnaround from 12z today which showed a full blown sub 980 mb apps runner. If the GFS changes this drastically between model runs, it means that it does not have a solid idea about what is going to happen with this storm. It also shows that nearly every single solution (except perhps a GLC) is on the table with this storm right now. The GEFS have been more consistent however with this storm, and the means have consistently showed a coastal with this storm with a few individual ENS heading inland, a few having a coastal, and a few OTS to help balance the mean out.

It will be interesting to see if the 0z ECMWF maintains what the 500 mb depiction looked like at 12z today, or if the GFS caved in to the Euro solution, and the ECMWF stays the same as 12z today. It will also be interesting to see if the UKMET changes as drastically as the GFS did from 12z to 0z, because it showed a similar track as the GFS did at 12z today (albeit not quite as strong as the GFS). Hopefully tonight we can get some better model agreement, and if not, then let the model madness continue.

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This can be a threatening look sometimes, with that shortwave diving down the east side of the PNA ridge and some cold air re-assertion over the area. But not in this pattern, with the SE Ridge likely to shunt the cold air out in between systems...and the lack of blocking likely to let that shortwave over the Pac NW take an unfavorable track.

http://www.meteo.psu.edu/~gadomski/AVN_0z/f156.gif

We are going to be off to a slow start this year, but we'll get through it.

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After that, it removes the SW US energy for the Saturday storm, which apparently isn't happening this run... could the GFS possibly get any more inconsistent?

The GFS has been horrible. The mean has been consistent with a coastal low. I don't think the depiction tonight will verify because there is no way the storm will go OTS with a +NAO,+AO and +PNA.

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