Inverted Trough/ Redeveloper Disco Jan 7-9

[CCPSUSuperstorm2010]

It seems that the NAM wants to intensify the H5 low once again around hour 72, what kind of screws us in this period is that the h5 low is too far to the north. If this H5 track verified to the south of the us, we will be in business as the third northern stream shortwave rotates around the H5 low and amplifies the H5 trough. Still we are 72 hours out on this energy as well. So much energy to solve, so little time. I definitely could see a case where the radar looks more promising around hour 30 than what the NAM is showing currently.

[Baroclinic Zone]

Nice big FU from the NAM for me.

[Clinch Leatherwood]

We're talking about the NAM and you can show whatever maps you want. It's had 8 different solutions for the last 8 runs.

Again go do a 500mb overlay of the 0z 12h forecast vs the 12z 0h init specifically with the s/w west of the lakes and north of ND and tell me how wonderful it is and how it's scoring.

Then look at the forecasts as they propogate out and see two massively different solutions. When it cannot forecast a 500mb position at 6-12 hours it has no hope of getting anything else right down the road.

[dryslot]

All I'm saying is we can't even go 6-12 hours without the major features being shuffled around and it's not just with this inverted trough.

Last storm we had "model errors" that turned out to be nothing of the sort. What we had was massive model flip flopping.

The earlier storm that gave 10+ down here was all over the map too.

I'm not basing NCEP or anyone else and I'm sure they're working it out but hardly a boston tv forecast goes by without someone saying they cannot rely on the models at this stage. Even the EC is jumping around.

What I don't get is how we can be seeing such wild (relatively) swings inside of 6-12 hours at 500mb on strength/positioning. Some bad data is getting in I think.

I agree with you, The model performance has been less then stellar, Wehter its the pattern or the changes that were made to some of the models i don't know, But i guess its goes back to the old days of forcasting 24-36 hrs out.

[OSUmetstud]

We're talking about the NAM and you can show whatever maps you want. It's had 8 different solutions for the last 8 runs.

Again go do a 500mb overlay of the 0z 12h forecast vs the 12z 0h init specifically with the s/w west of the lakes and north of ND and tell me how wonderful it is and how it's scoring.

Then look at the forecasts as they propogate out and see two massively different solutions. When it cannot forecast a 500mb position at 6-12 hours it has no hope of getting anything else right down the road.

[radarman]

You should be commended for even having a map that low for the post xmas event. I had heard one local met up here in spfd calling for just a half foot but every other forecast was well into the teens!!! I am not sure what happened over there in windsor locks but I know most of the valley had four to eight inches..in fact north of spfd in mid valley of mass there were places that had less than four inches..ie deerfield.

Last storm was impossible to measure. I am claiming 4.5" in my sig, but if I had tried measuring the next day I'd have been hard pressed to find much above 2".

I think it's quite possible the next 60 hours puts more snow on my lawn than the bomb did, and the fact that it's an anomalous meso-banded inverted trough setup I consider a good thing. I remember when the Sox were down 0-3 to the yanks in '04 Maddog Russo was saying on the radio that if the sox were ever going to win, the prelude would have to be some weird set of circumstances, a "cataclysmic event" he termed it. In this case, I am thinking of upside as being advisory criteria, but in general I say bring the atypical setups. These run-of-the-mill bombs consistently suck around here it seems.

[powderfreak]

Nice big FU from the NAM for me.

Looks like the GFS and NAM like Upstate NY...

I just cannot trust any of these QPF maps with a mesoscale event like a NORLUN. Its not like a meso-scale event that involves the lakes or topography where you can sort of at least nail down to a few counties... 10-15 miles is huge in this.

[CCPSUSuperstorm2010]

– as expected, the surface lags behind this very favorable 500mb level trend.

The 500mb is now “re”deepening to 504dm in the core, where the previous runs were trying to do the opposite and fill the vortex… That is an indication that there are physics in play for cyclogenesis – cyclogen processes lower heights and that is a positive feedback during development of the low in the lower levels (complicated). Anyway, seeing the heights go from 510dm to ripping open a 504dm hole near CC is a sign that the surface reflection is developing, not weakening, and doing so [probably ] in a favorable spot when all is said and done.

Best run yet my friends for compensating those super duper fast flows. This may go down as being purely a function of models having difficulty handling fast flow wave interactions - heh, goes without saying really. That does not mean we should go hog wild and correct this toward a juggernaut, but it certainly isn't hurting the enthusiast private dreams.

The intermediate/polar stream wave has been fully puked on-board off the Pacific and all dynamics are squarely in the denser western N/A grids in the morning's ingest. I think it is intriguing that the last 3 cycles of the NAM has closed the gap between it and the core of the closed beast on every run ... however tediusly small those increments have been. It is very close now to actually capturing it and if that does, look out! You go from a purely modeled blase' event to a all out rush to get the blizz notification to the public in short order.

I guess you could say that this was the favorable run we were looking for, although it is just one run picking up on this solution now, perhaps we are getting rid of the medium range horror show the models have been in since meteorological winter has begun. If this verified further to the south then currently shown on the NAM I think it is really cutting it close with my departure time on Tuesday. I go to BOS on Monday afternoon and if this storm is delayed any this weekend, I may not be able to enjoy it. Also Tuesday looks like the day in between behemoths.

[free_man]

Nice big FU from the NAM for me.

at least we know it'll change about 6 more times.

[40/70 Benchmark]

– as expected, the surface lags behind this very favorable 500mb level trend.

The 500mb is now “re”deepening to 504dm in the core, where the previous runs were trying to do the opposite and fill the vortex… That is an indication that there are physics in play for cyclogenesis – cyclogen processes lower heights and that is a positive feedback during development of the low in the lower levels (complicated). Anyway, seeing the heights go from 510dm to ripping open a 504dm hole near CC is a sign that the surface reflection is developing, not weakening, and doing so [probably ] in a favorable spot when all is said and done.

Best run yet my friends for compensating those super duper fast flows. This may go down as being purely a function of models having difficulty handling fast flow wave interactions - heh, goes without saying really. That does not mean we should go hog wild and correct this toward a juggernaut, but it certainly isn't hurting the enthusiast private dreams.

The intermediate/polar stream wave has been fully puked on-board off the Pacific and all dynamics are squarely in the denser western N/A grids in the morning's ingest. I think it is intriguing that the last 3 cycles of the NAM has closed the gap between it and the core of the closed beast on every run ... however tediusly small those increments have been. It is very close now to actually capturing it and if that does, look out! You go from a purely modeled blase' event to a all out rush to get the blizz notification to the public in short order.

Well, the 12z Tip is taking a page out of the DGEX book....didn't see that coming.

[Gibbsfreeenergy]

[amarshall]

Good read on the Norlun trough from Matt Noyes for noobs like me

http://www.mattnoyes.net/new_england_weather/2011/01/exactly-what-is-a-norlun-trough-and-how-do-you-forecast-weather-associated-with-it.html

[mattlacroix4]

MaineJayHawk is pretty much in the bullseye on this on the 12Z NAM, for what it's worth. Funny how the last 2 runs of the NAM went from less than .25 to almost .75 in spots in southwest Maine.

[Kbosch]

My weenie-ism from yesterday aside, I did not expect to get a WSW this morning - out of sheer uncertainty I take it? I knew we had the WWA locked in. The fact my area kept winning the last few days must have inspired them enough to think I have a good potential. Obviously

[OSUmetstud]

I think some of the idea that the models are awful or whatever comes from this constant microanalysis of dozens of runs a day going out several days due to the incredible amount of data available to everyone nowadays.. I think I've conceded that the models did do pretty bad for that snowstorm 2 weeks ago...but I see that as more of a fluke as opposed to "a huge step back" whatever that means...

We got a very difficult mesoscale set-up with the current storm...and we have several different shortwaves on a map with a moderate/strong La Nina and strong blocking...it's a very difficult pattern for models to deal with.

[40/70 Benchmark]

My weenie-ism from yesterday aside, I did not expect to get a WSW this morning - out of sheer uncertainty I take it? I knew we had the WWA locked in. The fact my area kept winning the last few days must have inspired them enough to think I have a good potential. Obviously

Make sure to post AFTER the event, too.

[CCPSUSuperstorm2010]

We look to be dealing with a highly uncertain pattern. Goes without saying really, but it would seem the QPF hole over SE MA and RI would be a big result from the H5 low tracking directly over our heads. I would venture to guess the H7 and H85 lows are in almost the same location. So therefore a track further to south if verified would really set in motion a potential blizzard like outcome around 60-84 hours, preceded by this inverted trough/half of a CCB like outcome producing snows in some areas and screwing other areas. Right now it looks like a wait and see pattern, so much energy going around in the mid level trough models have no clue how to handle them. A large trend has been observed with the northern stream energy around SD/MN at hour 30 on the 12z models is getting a tad faster each run. Maybe if the lead energy over the region at hour 30 could be a tad stronger and slower we could end up with several big snow solutions all within 96 hours.

[Kbosch]

Make sure to post AFTER the event, too.

You mean when my obvious amounts have obviously come? Obviously, I will.

They've done a great job with it. Hats off to them.

[40/70 Benchmark]

I think some of the idea that the models are awful or whatever comes from this constant microanalysis of dozens of runs a day going out several days due to the incredible amount of data available to everyone nowadays.. I think I've conceded that the models did do pretty bad for that snowstorm 2 weeks ago...but I see that as more of a fluke as opposed to "a huge step back" whatever that means...

We got a very difficult mesoscale set-up with the current storm...and we have several different shortwaves on a map with a moderate/strong La Nina and strong blocking...it's a very difficult pattern for models to deal with.

Absolutely....good point.

[mahk_webstah]

– as expected, the surface lags behind this very favorable 500mb level trend.

The 500mb is now “re”deepening to 504dm in the core, where the previous runs were trying to do the opposite and fill the vortex… That is an indication that there are physics in play for cyclogenesis – cyclogen processes lower heights and that is a positive feedback during development of the low in the lower levels (complicated). Anyway, seeing the heights go from 510dm to ripping open a 504dm hole near CC is a sign that the surface reflection is developing, not weakening, and doing so [probably ] in a favorable spot when all is said and done.

Best run yet my friends for compensating those super duper fast flows. This may go down as being purely a function of models having difficulty handling fast flow wave interactions - heh, goes without saying really. That does not mean we should go hog wild and correct this toward a juggernaut, but it certainly isn't hurting the enthusiast private dreams.

The intermediate/polar stream wave has been fully puked on-board off the Pacific and all dynamics are squarely in the denser western N/A grids in the morning's ingest. I think it is intriguing that the last 3 cycles of the NAM has closed the gap between it and the core of the closed beast on every run ... however tediusly small those increments have been. It is very close now to actually capturing it and if that does, look out! You go from a purely modeled blase' event to a all out rush to get the blizz notification to the public in short order.

Blizz has already been notifying us!

Great to hear your view on this. You always give a different perspective, looking for the things you pay attention to, and that is fun. Messenger does the same sort of thing. When the models suck this is the best way to get a handle....Thanks. These runs are fun to watch!

[Typhoon Tip]

I think some of the idea that the models are awful or whatever comes from this constant microanalysis of dozens of runs a day going out several days due to the incredible amount of data available to everyone nowadays.. I think I've conceded that the models did do pretty bad for that snowstorm 2 weeks ago...but I see that as more of a fluke as opposed to "a huge step back" whatever that means...

We got a very difficult mesoscale set-up with the current storm...and we have several different shortwaves on a map with a moderate/strong La Nina and strong blocking...it's a very difficult pattern for models to deal with.

Definitely agreed here! ...stepping back and seeing the the big picture is just as important, and often being muddled by accessive attention to detail on a D6 run - it's absurd actually.

[powderfreak]

Logan11/Rick gets destroyed by upslope enhancement on the eastern slope of the Helderbergs/Catskills (that form the western side of the Hudson Valley). His location at over 1,000ft there west of ALB would be a nice spot to be on some of these model runs.

[free_man]

I think there is some underplaying of ratios going on. These norluns can sometimes produce some of the most prolific ratios for NE (outside of the LE /orographic stuff). When I see .5-1" of qpf for ME in an inverted trof setup, I think 12"+

Still curious as to the wsw for NYC metro and NJ. Maybe fluff factor could be enough to push totals up there...

[Tropopause_Fold]

Absolutely....good point.

yes.

[mahk_webstah]

Looks like the GFS and NAM like Upstate NY...

I just cannot trust any of these QPF maps with a mesoscale event like a NORLUN. Its not like a meso-scale event that involves the lakes or topography where you can sort of at least nail down to a few counties... 10-15 miles is huge in this.

and NH and ME bay bee.

[Clinch Leatherwood]

That's not an overlay.

Here's the 12h 0z NAM forecast vs Init. Slight differences in strength and positioning in the two features which were entirely on land at the time (west of lakes which specifically left to its solution last night)

And below that the 24h 0z forecast, and now the 12h 12z. Just a SLIGHt change with the handling of the energy coming into PA entirely due to the crap 0h product from 0z last night. Paint it however you like, but it clearly had bad data that either didn't get caught or shows up elsewhere as the GFS did not have these issues.

Also a good illustration of why those verification scores aren't true to what's happening. The contours may not be moving all that much but the vorticity is, and it's being pegged poorly often in strength and position in the very, very short term. If we cannot get that right we can give up getting really accurate foreacasts long term.

[CCPSUSuperstorm2010]

I think some of the idea that the models are awful or whatever comes from this constant microanalysis of dozens of runs a day going out several days due to the incredible amount of data available to everyone nowadays.. I think I've conceded that the models did do pretty bad for that snowstorm 2 weeks ago...but I see that as more of a fluke as opposed to "a huge step back" whatever that means...

We got a very difficult mesoscale set-up with the current storm...and we have several different shortwaves on a map with a moderate/strong La Nina and strong blocking...it's a very difficult pattern for models to deal with.

It also had to do with the storm on Dec 20th/21st. That storm was modeled so far out to sea that there was no precip over the benchmark out to 24 hours on the global models. NAM was the only true model to have almost perfect verification with exception to its overdone QPF episodes what exactly happened about 24 hours out. Problem was almost everyone including myself needed to see support for this solution to actually belief, problem was that never occurred and the NAM was right. The models showed an inverted trough setup with that system as well within 12-24 hours from the time the snow started to fall. This is another example for the disgust in the model behavior recently, I think it has more to do with that snowstorm, then this norlun trough/inverted trough setup which I understand is quite hard, especially with about 4-5 shortwaves in the northern stream involved within the next 96 hours.

[Damage In Tolland]

– as expected, the surface lags behind this very favorable 500mb level trend.

The 500mb is now “re”deepening to 504dm in the core, where the previous runs were trying to do the opposite and fill the vortex… That is an indication that there are physics in play for cyclogenesis – cyclogen processes lower heights and that is a positive feedback during development of the low in the lower levels (complicated). Anyway, seeing the heights go from 510dm to ripping open a 504dm hole near CC is a sign that the surface reflection is developing, not weakening, and doing so [probably ] in a favorable spot when all is said and done.

Best run yet my friends for compensating those super duper fast flows. This may go down as being purely a function of models having difficulty handling fast flow wave interactions - heh, goes without saying really. That does not mean we should go hog wild and correct this toward a juggernaut, but it certainly isn't hurting the enthusiast private dreams.

The intermediate/polar stream wave has been fully puked on-board off the Pacific and all dynamics are squarely in the denser western N/A grids in the morning's ingest. I think it is intriguing that the last 3 cycles of the NAM has closed the gap between it and the core of the closed beast on every run ... however tediusly small those increments have been. It is very close now to actually capturing it and if that does, look out! You go from a purely modeled blase' event to a all out rush to get the blizz notification to the public in short order.

[radarman]

timestamp='1294325543'[/b] post='230083']

in general I say bring the atypical setups.

timestamp='1294325650[/b]' post='230097']

stupid atypical setups

[40/70 Benchmark]