Dec 11-13 MW/Lakes/OV Snow Event? Part III

[baroclinic_instability]

The strength of the jet coming in on the back side could cause more trough amplification. I think Oceanwx said this earlier today...why do the models keep placing the low this far north when the best upper level divergence is located to the south?

The coupled upper level jet streak on the eastern portion of the trough is far more conducive to large amounts of divergence. Also, and more importantly, the strength of the baroclinic zone near the Polar Vortex is extreme, and even weak upper divergence will set in motion a rapid cyclogenesis feedback process. Because of that, the northern solution will dominate. I just don't find the southern UK type solution realistic because incipient cyclogenesis will deepen farther N with a frontal wave extending southward.

[baroclinic_instability]

I bolded that part above because it is very important, and it isn't being mentioned here in some of these discussions. There is a secondary baroclinic zone farther S as many here are mentioning with a moist air mass, and as the UK does, it blows it up along that boundary But almost all guidance is trending to a more phased solution, so the incipient cyclogenesis will be along the northern boundary as opposed to the moist baroclinic zone down south. UK isn't phasing, hence its solution. Not saying UK can't happen, but it is looking less and less likely with time.

[Organizing Low]

Including us? Apparently the new UKmet doesn't look too bad

the trends arent good, no.

as i said, ill defer judgement until tomorrow 12z, but just speaking of the trends and where this seems to want to head, they arent good.

but i wouldnt throw in the towel until the 12z runs tomorrow at least.

[Stevo6899]

The coupled upper level jet streak on the eastern portion of the trough is far more conducive to large amounts of divergence. Also, and more importantly, the strength of the baroclinic zone near the Polar Vortex is extreme, and even weak upper divergence will set in motion a rapid cyclogenesis feedback process. Because of that, the northern solution will dominate. I just don't find the southern UK type solution realistic because incipient cyclogenesis will deepen farther N with a frontal wave extending southward.

What exactly went on with the 0z run of the NAM last night compared to todays NAM runs?

[Harry]

The coupled upper level jet streak on the eastern portion of the trough is far more conducive to large amounts of divergence. Also, and more importantly, the strength of the baroclinic zone near the Polar Vortex is extreme, and even weak upper divergence will set in motion a rapid cyclogenesis feedback process. Because of that, the northern solution will dominate. I just don't find the southern UK type solution realistic because incipient cyclogenesis will deepen farther N with a frontal wave extending southward.

You mind showing a example of a system that did just that? Mean i wanna see the jet/surface low track etc. Sorry but i cannot recall any and i have been at this a long time.

Thanks.

[baroclinic_instability]

What exactly went on with the 0z run of the NAM last night compared to todays NAM runs?

More phased solution which results in more CAA which tightens the baroclinic zone. Deep cyclogenesis is a feedback process, so that tiny change can result in massive forecast changes. Ed Lorenz and chaos theory explains it well in his paper "Deterministic Nonperiodic FLow". this is a good example why we can't realistically forecast beyond 1.5-2 weeks.

[Hoosier]

The coupled upper level jet streak on the eastern portion of the trough is far more conducive to large amounts of divergence. Also, and more importantly, the strength of the baroclinic zone near the Polar Vortex is extreme, and even weak upper divergence will set in motion a rapid cyclogenesis feedback process. Because of that, the northern solution will dominate. I just don't find the southern UK type solution realistic because incipient cyclogenesis will deepen farther N with a frontal wave extending southward.

Time will tell I guess. You've laid it out on the table which I commend.

[Baum]

You mind showing a example of a system that did just that? Mean i wanna see the jet/surface low track etc. Sorry but i cannot recall any and i have been at this a long time.

Thanks.

From Lincoln,Il AFD:

MODELS HAVE BEEN HAVING

CONSIDERABLE DIFFICULTY PINPOINTING THE EXACT LOCATION AND TRACK

OF THIS LOW...HOWEVER 12Z 9 DEC SOLUTIONS ARE COMING TO A MORE

NORTHERN CONSENSUS. THIS SEEMS REASONABLE GIVEN THE LIKELY

LOCATION OF THE BAROCLINIC ZONE LEFT BEHIND BY THE DEPARTING WAVE

TONIGHT. SINCE THE INITIAL WAVE IS TRACKING A BIT FURTHER NORTH

THAN PREVIOUSLY FORECAST AND THE COLD AIR BEHIND IT IS LAGGING

WELL TO THE NORTH ACROSS CANADA...THINK THIS SUGGESTS A FURTHER

NORTH POSITION OF THE FRONTAL ZONE. AS NEXT WAVE APPROACHES LATE

FRIDAY...SURFACE LOW WILL DEVELOP AND TRACK ALONG THIS FRONT. WITH

THAT BEING SAID...LATEST MODEL RUN IS SHOWING A CLUSTER OF

SOLUTIONS TAKING LOW PRESSURE FROM IOWA EARLY SATURDAY MORNING

ACROSS FAR NORTHERN ILLINOIS INTO SOUTHERN MICHIGAN BY SATURDAY

NIGHT. ONLY THE UKMET AND CANADIAN HANG ON TO A FURTHER SOUTH LOW

TRACK ACROSS CENTRAL ILLINOIS. THE UKMET APPEARS TO BE TOO

AMPLIFIED WITH THE UPPER WAVE...FORMING A DEEP CLOSED LOW OVER

WESTERN TENNESSEE BY 12Z SUN. HAVE THEREFORE THROWN OUT THIS

SOLUTION IN FAVOR OF A BLEND BETWEEN THE NAM/GFS/ECMWF NORTHERN

TRACK AND THE CANADIAN. THIS WILL TAKE THE LOW ACROSS NORTH-CENTRAL

ILLINOIS ON SATURDAY...THEN INTO NORTHERN INDIANA/OHIO SATURDAY

NIGHT.

[baroclinic_instability]

You mind showing a example of a system that did just that? Mean i wanna see the jet/surface low track etc. Sorry but i cannot recall any and i have been at this a long time.

Thanks.

I could show you seemingly a ton, quite honestly. Do you want a lesson in atmospheric dynamics? Your example is a very simplistic conceptual model taught in Met 101 books, but the reality is it is much more complex. Many phased events with deep cyclogenesis exhibit upper level jet couplings. Look at superstorm 1993 for a spectacular example.

[The_Global_Warmer]

More phased solution which results in more CAA which tightens the baroclinic zone. Deep cyclogenesis is a feedback process, so that tiny change can result in massive forecast changes. Ed Lorenz and chaos theory explains it well in his paper "Deterministic Nonperiodic FLow". this is a good example why we can't realistically forecast beyond 1.5-2 weeks.

More like 1.5 days.

thanks for explaining this.

[Stevo6899]

More phased solution which results in more CAA which tightens the baroclinic zone. Deep cyclogenesis is a feedback process, so that tiny change can result in massive forecast changes. Ed Lorenz and chaos theory explains it well in his paper "Deterministic Nonperiodic FLow". this is a good example why we can't realistically forecast beyond 1.5-2 weeks.

So you dont think that is possible? Since they aren't phasing the baroclinic zone is further north and lows track along the baroclinic zone correct? Thanks for the input

[L.B. LaForce]

[baroclinic_instability]

So you dont think that is possible? Since they aren't phasing the baroclinic zone is further north and lows track along the baroclinic zone correct? Thanks for the input

No it can happen, but I give the UK a very small chance, less than 10%. Cyclogenesis of this sort is VERY sensitive, and a tiny track change of the southern stream upper wave could result in massive differences. Still though, UK is not a very valid solution at this point.

[Stebo]

Consensus

[A-L-E-K]

new HPC low tracks scream dry slot and game set match.

[Stevo6899]

No it can happen, but I give the UK a very small chance, less than 10% Cyclogenesis of this sort is VERY sensitive, and a tiny track change of the southern stream upper wave could result in massive differences. Still though, UK is not a very valid solution at this point.

Yea I figured that. Why all the troubles with the models? There are two different lows and they dont phase. Must be hard for the models to depict transfers and if or when a low is going to split into two storms?

[csnavywx]

I bolded that part above because it is very important, and it isn't being mentioned here in some of these discussions. There is a secondary baroclinic zone farther S as many here are mentioning with a moist air mass, and as the UK does, it blows it up along that boundary But almost all guidance is trending to a mroe phased solution, so the incipient cyclogenesis will be along the northern boundary as opposed to the moist baroclinic zone down south. UK isn't phasing, hence its solution. Not saying UK can't happen, but it is looking less and less likely with time.

Most of the cyclogenesis being generated by the models is in association with a lead shortwave. If the strength of that wave has been misanalyzed due to the data void over the Pacific (as in, the vort is too weak when it emerges off the Rockies), then the left exit region of that shared energy jet will dominate. Hence the flip-flopping on the solutions. The thermal gradient with the northern boundary is substantial, no doubt about it, and we also have to deal with track differences due to the actual location of that boundary. It is arctic air, and these typically end up further south than progged. And then we have the snowpack orientation to deal with... etc etc. Too many variables in the air still. Get this sucker over land, and check back tomorrow at 12Z when it's sampled and onshore.

Until then, I have a hard time, from a meteorological standpoint, about believing robust cyclogenesis without a better defined wave. That self-development/feedback process should be slow at first, especially given the relative lack of jet support to start with that far north. If the boundary was being depicted further south, I'd buy it. Otherwise, this is going to have an ESE track and weaker SLP for quite a while.

[buckeye]

From Lincoln,Il AFD:

MODELS HAVE BEEN HAVING

CONSIDERABLE DIFFICULTY PINPOINTING THE EXACT LOCATION AND TRACK

OF THIS LOW...HOWEVER 12Z 9 DEC SOLUTIONS ARE COMING TO A MORE

NORTHERN CONSENSUS. THIS SEEMS REASONABLE GIVEN THE LIKELY

LOCATION OF THE BAROCLINIC ZONE LEFT BEHIND BY THE DEPARTING WAVE

TONIGHT. SINCE THE INITIAL WAVE IS TRACKING A BIT FURTHER NORTH

THAN PREVIOUSLY FORECAST AND THE COLD AIR BEHIND IT IS LAGGING

WELL TO THE NORTH ACROSS CANADA...THINK THIS SUGGESTS A FURTHER

NORTH POSITION OF THE FRONTAL ZONE. AS NEXT WAVE APPROACHES LATE

FRIDAY...SURFACE LOW WILL DEVELOP AND TRACK ALONG THIS FRONT. WITH

THAT BEING SAID...LATEST MODEL RUN IS SHOWING A CLUSTER OF

SOLUTIONS TAKING LOW PRESSURE FROM IOWA EARLY SATURDAY MORNING

ACROSS FAR NORTHERN ILLINOIS INTO SOUTHERN MICHIGAN BY SATURDAY

NIGHT. ONLY THE UKMET AND CANADIAN HANG ON TO A FURTHER SOUTH LOW

TRACK ACROSS CENTRAL ILLINOIS. THE UKMET APPEARS TO BE TOO

AMPLIFIED WITH THE UPPER WAVE...FORMING A DEEP CLOSED LOW OVER

WESTERN TENNESSEE BY 12Z SUN. HAVE THEREFORE THROWN OUT THIS

SOLUTION IN FAVOR OF A BLEND BETWEEN THE NAM/GFS/ECMWF NORTHERN

TRACK AND THE CANADIAN. THIS WILL TAKE THE LOW ACROSS NORTH-CENTRAL

ILLINOIS ON SATURDAY...THEN INTO NORTHERN INDIANA/OHIO SATURDAY

NIGHT.

the nam seems just as amp'd as the ukmet, (see my post above), only diff is it's not closing off the low.

[Hoosier]

No it can happen, but I give the UK a very small chance, less than 10%. Cyclogenesis of this sort is VERY sensitive, and a tiny track change of the southern stream upper wave could result in massive differences. Still though, UK is not a very valid solution at this point.

UKMET is a southern outlier so you're probably right...never good to lean toward an outlier (unless it's the Euro ) but I think there's enough spread to not write this thing off around for those near the southern edge of the NAM/Euro heavy snow band.

[Harry]

Most of the cyclogenesis being generated by the models is in association with a lead shortwave. If the strength of that wave has been misanalyzed due to the data void over the Pacific (as in, the vort is too weak when it emerges off the Rockies), then the left exit region of that shared energy jet will dominate. Hence the flip-flopping on the solutions. The thermal gradient with the northern boundary is substantial, no doubt about it, and we also have to deal with track differences due to the actual location of that boundary. It is arctic air, and these typically end up further south than progged. And then we have the snowpack orientation to deal with... etc etc. Too many variables in the air still. Get this sucker over land, and check back tomorrow at 12Z when it's sampled and onshore.

Until then, I have a hard time, from a meteorological standpoint, about believing robust cyclogenesis without a better defined wave. That self-development/feedback process should be slow at first, especially given the relative lack of jet support to start with that far north. If the boundary was being depicted further south, I'd buy it. Otherwise, this is going to have an ESE track and weaker SLP for quite a while.

Thank you..

Do you believe such a track would happen with that jet etc?

[MadTown]

this is rediculous... i think madison is to far south for this one

[Ottawa Blizzard]

the trends arent good, no.

as i said, ill defer judgement until tomorrow 12z, but just speaking of the trends and where this seems to want to head, they arent good.

but i wouldnt throw in the towel until the 12z runs tomorrow at least.

Interesting that the weather network has joined in the hype by saying there could be over a foot of snow with this along the Ontario-Quebec border. Perhaps they don't want to risk a debacle similar to what happened in montreal this week?

Also interesting that Joe Bastardi hasn't updated his blog since last night when he was calling for a blizzard in the lower lakes.

[snowstormcanuck]

48 hour RGEM has a 1004 over Quad Cities.

[Chicago Storm]

Umm.. That had a surface low track from the GOM and up the eastcoast if i recall correctly? The energy dived down into texas as well. I don't recall a northern low like this? Feel free to post the images from that storm from development on.

All i want is images of such a system. Very easy to sit there and try to explain it away as you are doing.

And pardon me but i suspect your backyard is playing a bit into all of this.

If I remember correctly he's actually in Michigan right now, so...

[baroclinic_instability]

Most of the cyclogenesis being generated by the models is in association with a lead shortwave. If the strength of that wave has been misanalyzed due to the data void over the Pacific (as in, the vort is too weak when it emerges off the Rockies), then the left exit region of that shared energy jet will dominate. Hence the flip-flopping on the solutions. The thermal gradient with the northern boundary is substantial, no doubt about it, and we also have to deal with track differences due to the actual location of that boundary. It is arctic air, and these typically end up further south than progged. And then we have the snowpack orientation to deal with... etc etc. Too many variables in the air still. Get this sucker over land, and check back tomorrow at 12Z when it's sampled and onshore.

Until then, I have a hard time, from a meteorological standpoint, about believing robust cyclogenesis without a better defined wave. That self-development/feedback process should be slow at first, especially given the relative lack of jet support to start with that far north. If the boundary was being depicted further south, I'd buy it. Otherwise, this is going to have an ESE track and weaker SLP for quite a while.

Indeed initial cyclogenesis is strongly supported through the initial contribution to DCVA. Regarding flip-flopping, I do seem to see a much stronger consensus towards a phased solution which would result in a much tighter baroclinic zone and enhanced jet pattern (as the upper level cold front orients itself over the low level baroclinic zone) and a rapid uptick in cyclogenesis as the system progresses east. It may not be sampled yet by the network but satellite obs can still do a fine job catching on to where the upper wave is.

Also worth noting with recent trends is how far the cold air developed south with this current clipper. Looking at past runs they are taking it a tad farther S, therefore phasing being the much more likely scenario with each successive run. I think the general trend farther N can be largely attributed to this.

[Harry]

If I remember correctly he's actually in Michigan right now, so...

Not what his location says. Either way i can assure all we wont have a track that far nw ( not with that ) and if we do Hoosier can have my account deleted here. Thats how certain i am.

[Hoosier]

48 hour RGEM has a 1004 over Quad Cities.

A bit south of the NAM, and anecdotally speaking, it seems like this model is often too far north at 48 hours.

[Hoosier]

Not what his location says. Either way i can assure all we wont have a track that far nw ( not with that ) and if we do Hoosier can have my account deleted here. Thats how certain i am.

lol...no need for crazy talk like that Harry.

[on_wx]

Consensus

I blame the Monday night radio show

[baroclinic_instability]

Not what his location says. Either way i can assure all we wont have a track that far nw ( not with that ) and if we do Hoosier can have my account deleted here. Thats how certain i am.

Read my post about 5 pages back/2 hours ago about the CMC being the solution of choice at this time.