12Z Model Thread 12/22

[Guest someguy]

FOLKS the 12z euro certainly could shift east 100 miles and come more in line with the 0z ens mean

so for eastern va nc that would be what 10" instead of 20" ... Golly not that

[vinylfreak89]

huge changes this run... I think I see 2 major key synoptic pieces that fall in to play.

1) the northern energy must stay consolidated and not strung out

2) no energy or very little can get left behind in the baja from the STJ feature.

the smaller details like the speed of the next storm crashing in to the pacific NW, the position of the NW atlantic cyclops, the quebec low etc I wouldn't worry about for another day or two. I want to see a consistent day of runs from all the models with those first two points. then i think we are on to something for a pretty massive hit for the entire EC.

Note that if those 2 things dont happen, tthat doesn't mean no storm. depending on the other factors, I think we see at least a moderate event at least in the SE and SNE...the midatlantic may get the screw job though unless things come together perfectly... that is IF those 2 key points I outlined DONT occur.

also, I see a higher potential of overrunning before the event starting to come in to play, maybe for some light snow christmas day... but those details are still pretty far away from being ironed out.

overall, I like the trends and if the UKIE is an eastern outlier in the 12Z model guidance I will be very happy.

[kpantz]

FOLKS the 12z euro certainly could shift east 100 miles and come more in line with the 0z ens mean

so for eastern va nc that would be what 10" instead of 20" ... Golly not that

True, but think of us poor folks north of the m/d line who really need this thing to wrap up and put down decent QPF 50-75 miles west of I-95. We're on the razor's edge, so to speak.

[LakeEffectKing]

FOLKS the 12z euro certainly could shift east 100 miles and come more in line with the 0z ens mean

so for eastern va nc that would be what 10" instead of 20" ... Golly not that

I think a few folks further up the coast might want the euro to get just a bit further north than it's 00z...

[dtk]

he's choo choosing not to hang out for the 12Z. That's a solid way to interpret it. Add in the GFS SE bias, shake well and sprinkle in the EURO and we've got ourselves a doozy.

My thoughts exactly Dave. Surface isn't matching up with the H5. Did I see Charlie poking his head around the corner?

Why do people always think they are smarter than the model itself when it comes to its surface reflection? If you want to talk about the overall evolution, placement of QPF, even the westward tilt being too steep/shallow, fine, but to act like the model is clueless about the surface reflection and to just say "it doesn't match up" drives me crazy. Just saying look at 5h and using your imagination is not an explanation.

BTW, I'm as glad as anyone to see a trend in the right direction, but there is still no guarantee this pans out. This is still a fairly complex evolution/interaction that needs to take place (this has been stated elsewhere)....minor changes in the initialization and/or evolution of some of the necessary pieces could potentially yield quite a different solution. The ensembles have been screaming from the rooftops there is still a LOT of uncertainty, run after run.....

[showmethesnow]

FOLKS the 12z euro certainly could shift east 100 miles and come more in line with the 0z ens mean

so for eastern va nc that would be what 10" instead of 20" ... Golly not that

Think you would be good down your way either way but wouldn't a 100 mile shift basically leave everybody out from DC to the north except for maybe NE?

[SACRUS]

GGEM out to 48

[baltimoreguy]

Yeah, seeing as it moved over that in 6 hours!!

To me, it seems like this is the first run that the GFS has finally begun to figure out the southern stream. If that's the case, doesn't it make it kind of meaningless to compare this run of the GFS to all prior runs?

[SACRUS]

and 60

[IsentropicLift]

My thinking is...the 12z euro holds serve and the 00z GFS which should have a better sampaling of the southern stream energy by then continues to trend towards the coast. My reasoning is backed by HPC which has been favoring the EC all along...and lends support to the idea that its higher res is giving it an advantage for ths system.

[vinylfreak89]

Why do people always think they are smarter than the model itself when it comes to its surface reflection? If you want to talk about the overall evolution, placement of QPF, even the westward tilt being too steep/shallow, fine, but to act like the model is clueless about the surface reflection and to just say "it doesn't match up" drives me crazy. Just saying look at 5h and using your imagination is not an explanation.

BTW, I'm as glad as anyone to see a trend in the right direction, but there is still no guarantee this pans out. This is still a fairly complex evolution/interaction that needs to take place (this has been stated elsewhere)....minor changes in the initialization and/or evolution of some of the necessary pieces could potentially yield quite a different solution. The ensembles have been screaming from the rooftops there is still a LOT of uncertainty, run after run.....

an important part of the equation to determine surface reflection is vorticity and thickness packing. i dont think the model is handling either of those too well at this moment, which leads to the poor surface reflection. so the model physics are dead on should the vorticity evolve the way the model indicates... I'm just not so sure thats going to be the case.

I guess my point is you have to consider a lot more than geopotential height, mslp and QPF.

[NortheastPAWx]

Can't really tell from the B/W maps but it looks like the northern stream is dropping a good bit south on this run.

EDIT: Check that, compared to the GFS it looks like it's moreso the H5 low being further north.

[mitchnick]

I would like to see some model support from our neighbors to the north.

we will imho looking at 60 hrs

the 540 line is much further north this run, into southern/central VA

I would expect it to come further west and north as a result

[Hailstorm]

What happened to the surface reflection at hour 60 on the 12 GGEM? My guess it would be in Southeastern Texas.

[SACRUS]

Just a s note you may have to hit crtl - F5 (refresh) for the candaian maps to update. For some reason they have a tendency to stick and yuo need to clear your cache.

[vinylfreak89]

To me, it seems like this is the first run that the GFS has finally begun to figure out the southern stream. If that's the case, doesn't it make it kind of meaningless to compare this run of the GFS to all prior runs?

the southern stream to an extent... it still swallows it a bit too easily... I think the biggest change is more consolidation in the northern stream.

one thing i will say... my idea on the pacific jet and the WPAC ridge being a factor here was way off... I'm still trying to figure out WHY the model is consolidating the energy more... to me its not enough to see trends but to see why they are established. my physics knowledge probably isn't developed enough to understand this however, so I will defer if a pro met wants to chime in.

[yoda]

Can't really tell from the B/W maps but it looks like the northern stream is dropping a good bit south on this run.

EDIT: Check that, compared to the GFS it looks like it's moreso the H5 low being further north.

Here's the color at 60 for help to see the northern stream energy dropping in

[LocoAko]

an important part of the equation to determine surface reflection is vorticity and thickness packing. i dont think the model is handling either of those too well at this moment, which leads to the poor surface reflection. so the model physics are dead on should the vorticity evolve the way the model indicates... I'm just not so sure thats going to be the case.

I guess my point is you have to consider a lot more than geopotential height, mslp and QPF.

First off, dtk works at NCEP, so I'm sure he knows that.

Secondly, that wasn't his point. Lots of people agree and run with the 500hPa evolution and then claim the surface low "positioning" is wrong compared to the upper levels. You're just stating that the upper level progression might not be right but that the surface agrees due to basic physics, which is exactly what dtk said in the first place.

[mitchnick]

Here's the color at 60 for help to see the northern stream energy dropping in

Canadian vortex well N & E

another good sign

[Zir0b]

s/w a good bit slower also , northern stream energy stronger....all signs point to a bomb

[bmorelights]

To me, it seems like this is the first run that the GFS has finally begun to figure out the southern stream. If that's the case, doesn't it make it kind of meaningless to compare this run of the GFS to all prior runs?

As far as I remember, the GFS wasn't on board with last year's december snowpocalypse southern stream either, was it?

[CoastalWx]

12z ensembles def came west. 1008mb low about 80-100 miles ese of ILM at hr 96. Low moves to about 200+ miles or so east of ORF as a 997 low. at hr 120 it's about 130miles east of the BM as a sub 990 low. Not bad for ensembles.

[NortheastPAWx]

Here's the color at 60 for help to see the northern stream energy dropping in

That's better...yeah, compared to the GFS the H5 low is further NE. However, I think the confluence is a bit further south.

Northern stream about the same.

[yoda]

72 B&W 1012 L in GOM

[Guest someguy]

MAJOR SHIUFT WEST IN THE HEAVY PRECIP ON GFS ENSEMBLE MEAN

http://raleighwx.americanwx.com/models/gfsensemble/12zgfsensemblep72120.gif

[SACRUS]

72

[A-L-E-X]

12z ensembles def came west. 1008mb low about 80-100 miles ese of ILM at hr 96. Low moves to about 200+ miles or so east of ORF as a 997 low. at hr 120 it's about 130miles east of the BM as a sub 990 low. Not bad for ensembles.

Looks like there is definitely room for further improvement from the GFS.

[SACRUS]

84

[vinylfreak89]

First off, dtk works at NCEP, so I'm sure he knows that.

Secondly, that wasn't his point. Lots of people agree and run with the 500hPa evolution and then claim the surface low "positioning" is wrong compared to the upper levels. You're just stating that the upper level progression might not be right but that the surface agrees due to basic physics, which is exactly what dtk said in the first place.

that comment wasn't directed at dtk, ti was meant to expand on his point... sorry for the confusion.

[Hailstorm]

The precipitation shield on the 12z GGEM at 72 hours looks more expansive than the 12z GFS and extends more northward. Good trends.