Midwest Thanksgiving Storm...

[msp]

Many of the 12z GFS individual ensemble members have a good storm, with some cutting up west of Chicago.

quite a bit of variation, but a couple members would give MN another healthy helping of the white stuff. P004 is a classic heavy snowstorm for msp and many of the others show weaker but similar solutions.

i'm sure mnweather would take this:

[mnweather]

quite a bit of variation, but a couple members would give MN another healthy helping of the white stuff. P004 is a classic heavy snowstorm for msp and many of the others show weaker but similar solutions.

i'm sure mnweather would take this:

I will take it but how strong of a storm are we looking at here.

[Moneyman]

970 MB LOW Pressure just east of MSP. 50-60 mph winds and 1-2 feet of snow for MSP.

[msp]

I will take it but how strong of a storm are we looking at here.

any single ensemble member doesn't mean much at all. right now, i wouldn't venture into saying much about storm strength given the wide range of track and evolution possibilities. atm, it's just worth stating the obvious that there's a chance msp could see a good snow out of this.

[BowMeHunter]

Euro looks about par for the weather the last 3 months outside of ocotobomb. Give all of us except the few in the sticks up north the most possible boring outcome along with pushing out the cold air fast.. At least the Euro doesn't keep me pinched inside the west end of a boring trough that's about as useless as palm tree's in WI. Up north in MN and WI do OK this run.. Building snowpack up there is not a bad thing for us.

Now that msp is in Texas, MSP can have their snow back.. We better hope his school breaks last a long time so we get some chances this winter

[Omahawx]

This storm and pattern reminds me of the late Octobomb..hmm

Looks much more impressive on raleigh weather version;

[TruePatriot]

I am driving from minneapolis to la crosse on thanksgiving. Hope the models are wrong, got pelted with 10 inches last storm.

[BowMeHunter]

I am driving from minneapolis to la crosse on thanksgiving. Hope the models are wrong, got pelted with 10 inches last storm.

We don't feel sorry for you J/K and have a safe drive.

John Dee doesn't give a mention of this storm potential, weird.

[mnweather]

We don't feel sorry for you J/K and have a safe drive.

John Dee doesn't give a mention of this storm potential, weird.

He did earlier this week and now he mentions that he thinks there will be no major storms. I wonder if he will change his tune again.

[AppsRunner]

Lock it in, Now i need someone to show me the jma and the korean model please. I won't feel comfortable until i see all possible models. I almost forgot someone post the FIM as well.

It's a lock now...

[JoMo]

FIM has an over-running event actually. Couple of the GFS Ensemble members did as well.

[baroclinic_instability]

Why are we using the NAM for long range questions on the storm when the NAM can't even forecast the first 2 ejecting waves with any consistency?

[k***]

Why are we using the NAM for long range questions on the storm when the NAM can't even forecast the first 2 ejecting waves with any consistency?

weenies gon weenie

[Organizing Low]

even though i am skeptical as previously mentioned, i am impressed that various runs of various models have all shown at some point an impressive CAD signature. an interesting detail that is emerging in the pattern.....

as for the storm itself, if there even is one, who knows. it will be a few more days yet...

[OceanStWx]

the battle between 12Z & 0Z runs continues....

This is a good time to point out that because of difference in how each model phases the energy, there are going to be some wild swings in individual solutions. Cherry picking any one run isn't very helpful, but trends may be insightful.

[Ajdos]

18z is more phased w/n stream

[Moneyman]

18z GFS gives WI around 5 inches of snow. I'll take it

[mnweather]

18Z still has no huge system yet.

[snowstormcanuck]

Storm really gets shredded up as it heads east. The D4-5 storm strengthens the confluence over the Great Lakes.

[JoMo]

Wake me up in 16 days unless the GFS changes it's tune. Looks boring.

[snowstormcanuck]

18z GFS BUFKIT outputs 2.6" of snow at YYZ on Thursday. Lock it in.

[Stebo]

Another day another myriad of solutions. At this point I'm kind of happy some are showing weak surpressed, this is the range that this would happen where the models will lose a storm or make it grossly underdone to the amount of energy being ejected. I'm sure the 00z will show something different too.

Of the models, the GGEM and the LOLGAPS are still staying consistent with the stronger solution, the Euro is flip-flopping and GFS is suppressed. Boy I feel for a forecaster this holiday week, interestingly enough, I feel we have said this a lot in recent years the week of thanksgiving.

[snowstormcanuck]

Another day another myriad of solutions. At this point I'm kind of happy some are showing weak surpressed, this is the range that this would happen where the models will lose a storm or make it grossly underdone to the amount of energy being ejected. I'm sure the 00z will show something different too.

What do you make of the EURO/GGEM solution of wrapping the storm up towards Lk Superior. I know I was saying earlier that I thought a further west solution was more likely but it looks like they're rapidly occluding these storms too deep into the cold air. I kind of get the sense they're suffering the same problem they did with the Nov 5-6 non-storm.

[Stebo]

What do you make of the EURO/GGEM solution of wrapping the storm up towards Lk Superior. I know I was saying earlier that I thought a further west solution was more likely but it looks like they're rapidly occluding these storms too deep into the cold air. I kind of get the sense they're suffering the same problem they did with the Nov 5-6 non-storm.

Its possible but what it looks like is its forming a surface low in conjunction with the northern stream energy and then drawing the Southern stream up as it moves into the region.

[baroclinic_instability]

That is a really good question. The level of uncertainty is enormous and anyone making de facto claims are simply not making them in any sort of truth. The operational and ensembles are all over the map and have no consistent trend. The only trend is the GFS with its positive tilt. In terms of probability, with the final trough, I would say the best chances for accumulating snow would be Wisconsin and into the northern Great Lakes heading into the NE with mild cyclogenesis, but not a superbomb like the CMC. Rain seems the most likely scenario almost any way you look at it for areas heading south into central Indiana/Illinois/Ohio Valley except northern Indiana/Ohio with some potential lake effect snow. Chicago will be a tough call, they are right in the middle of this. It does seem reasonable they will see at least some winter precipitation.

For now I am still thinking with my previous thoughts last night. I see no reason to think otherwise. Those hoping for global armageddon and a 960 bomb should look elsewhere.

[Stebo]

For now I am still thinking with my previous thoughts last night. I see no reason to think otherwise. Those hoping for global armageddon and a 960 bomb should look elsewhere.

Yeah I'd agree there won't be a major bomb with this, but I do think a decently strong system could be in the cards, I'd think the least likely solution right now is the GFS.

[baroclinic_instability]

I like the enthusiasm, but we need to start getting realistic and look at reality. As we have now seen with each model run, regardless of where it comes from, this storm is going to break down into a number of successive waves, and all models feature a positive tilt. Even with that, there can be expected to be a decent amount of cyclogenesis, but this storm is unlikely to wrap into a massive bomb with a positive tilt. Why? Let us just think of this from a synoptic meteorology perspective. First, all models are trending farther north with the final wave. Why does that matter? Gulf Flow and warm air advection combined with strong effects of diabatic heating due to latent heat release can ALTER the upper level height field. In other words, if warm air advection dominates low levels, remember from QG theory (QG Chi) heights will rise aloft. This increases the tilt--in other words, a strong PV Anomaly can take on a negative tilt even with a previously positive tilt trough, and strong amounts of vorticity advection aloft are advected by the geostrophic wind with further increases cyclogenesis. This becomes a positive feedback effect. This is looking less likely with each run as the models don't develop a large trough near the Gulf. Given that, the size of the trough and the amount of baroclinity along the boundary will still allow respectable cyclogenesis and a decent system over the Great Lakes/Wisconsin and possibly northern MN. But not a 960 bomb, I find a blend between CMC and GFS realistic in terms of intensity.

I did a long synoptic diagnosis in an earlier post about the northern plains winter storm dealing with synoptics and how they develop cyclones and how models can stink it up. http://jasonahsenmac...nt-1112-142010/

[Hoosier]

I like the enthusiasm, but we need to start getting realistic and look at reality. As we have now seen with each model run, regardless of where it comes from, this storm is going to break down into a number of successive waves, and all models feature a positive tilt. Even with that, there can be expected to be a decent amount of cyclogenesis, but this storm is unlikely to wrap into a massive bomb with a positive tilt. Why? Let us just think of this from a synoptic meteorology perspective. First, all models are trending farther north with the final wave. Why does that matter? Gulf Flow and warm air advection combined with strong effects of diabatic heating due to latent heat release can ALTER the upper level height field. In other words, if warm air advection dominates low levels, remember from QG theory (QG Chi) heights will rise aloft. This increases the tilt--in other words, a strong PV Anomaly can take on a negative tilt even with a previously positive tilt trough, and strong amounts of vorticity advection aloft are advected by the geostrophic wind with further increases cyclogenesis. This becomes a positive feedback effect. This is looking less likely with each run as the models don't develop a large trough near the Gulf. Given that, the size of the trough and the amount of baroclinity along the boundary will still allow respectable cyclogenesis and a decent system over the Great Lakes/Wisconsin and possibly northern MN. But not a 960 bomb, I find a blend between CMC and GFS realistic in terms of intensity.

I did a long synoptic diagnosis in an earlier post about the northern plains winter storm dealing with synoptics and how they develop cyclones and how models can stink it up. http://jasonahsenmac...nt-1112-142010/

Was anything ever indicating a 960 mb storm? I know the 12z Euro from yesterday was sub 980 mb but that was about the deepest I saw.

[JoMo]

Still a few showing overrunning and even a weak wave on the front.

P002 will be my new best friend if it's just a little farther to the NW.

[cyclone77]

One thing I don't like at all with the potential system is the strung out NE/SW oriented precip in the warm sector. This type of setup always "robs" moisture from the cold sector of the storm.

Sort of disappointed by the lack of storminess with the 12z runs, but there's still huge potential. Very deep trough, powerful arctic intrusion, open gulf, and very strong baroclinicy. We may not get a huge single storm, but at the very least we'll definitely get one or two strong waves rippling through the flow which could still deposit significant precip in certain areas. Both the GEM and the Euro latched onto something quite significant yesterday morning. The GFS has shown signs of latching onto the same idea. To me there's still a strong possibility that we will end up with one very strong storm system. Definitely going to be fun to watch/track.