Model Mayhem!

[Baroclinic Zone]

10 minutes ago, OceanStWx said:

Early December has followed the trends from before the upgrade. Euro still tops, but GFS challenging Ukie and beating CMC.

its the perception that people have when models struggle in our general area.  New England on the whole is a small geographical area when you compare it to the domain you're referencing above.  It's knowing those weaknesses in the models that make one a better forecaster.

[OceanStWx]

Just now, Baroclinic Zone said:

its the perception that people have when models struggle in our general area.  New England on the whole is a small geographical area when you compare it to the domain you're referencing above.  It's knowing those weaknesses in the models that make one a better forecaster.

We've said for a long while that the GFS doesn't spit the bit completely in progressive patterns. This is a progressive pattern, so it wouldn't be surprising if it performed well.

Will is right though, the placement of the high pressure seems to be determining quite a bit of the precip placement on the individual ensemble members.

[mahk_webstah]

a reassuring point to me is that WPC, though having no defined system in our area the next 7 days, continues to have a significant qpf.  In their latest, all of NE is over .75 inch qpf in the next 7 days and many of us are over1 inch.  That makes me think I get 6-12 over the next 7 days.  Must be the ensembles (NAEFS?) showing a strong qpf signal.

[ORH_wxman]

It's funny looking at the GFS and Euro H5. There really are a lot of similarities to the 2008 event. It's not exact of course but they are both developing that little split flow to the north(GFS is a little more so) which strengthens the high and what's the funny too is something most people do not remember...but the '08 system started off as a stemwound lakes cutter about 6/7 days out too...I vividly remember the mass panic about how December was going to be a dud for those who didn't get the epic ice storm. Things changed quickly on the models. 

 

Don't take this as a forecast for a repeat though. This one could still end up amped but I do like the trends this far. 

[Typhoon Tip]

the header indicates that product is for 'NHX' ...i presume to mean the entire hemisphere? 

i ask because i would be surprised to find that is true in quadrature. 

if we slice out just the north american ..sort of "quadraspheric" realm and score it as a subset, i wonder if doesn't score worse compared to the whole: the D 4 - 8 range ( assume to be late middle range).  granularity in the score results (at least intuitively) seems that it must exist.  

hypothetically, the model may be perfect over Japan and only c+ over Madagascar ... the "mad" guy may wonder why everyone's so reliant on the euro.

or not ... just sayn'.  

also, that product doesn't specify how much data is in the running (total results)/n-terms; a point that was central to the original question: ".. ...not sure we have that much data given to the youthfulness of this recent upgrade... ."  if the score is comparing 4 years of data in one product against 18 months of data in the other, i'd caution using that comparison. heh, you'd think who ever is putting those stats together has the scientific foresight not to mix match chi-test but then again ... that product did originate from a government agency so you never know -...  j/k 

i happen to know that since this autumn, the GFS has not performed as badly as it used to from ORD to BOS corridor in the late middle range for significant impact - modeled scenarios. and, as the euro has had more amplitude (and always seems to in that time range in question) that hasn't verified too well, ...i dunno - i warned people not to buy into the euor's wound up torque jobs and keep getting proven right when two cycles later, the depiction abandons the notion for a reason.  it has to do with both a-priori education/wisdom about matters combined with these observations.  yet those darn verifications keep saying Trump won the election - okay...  interesting. 

 

[Typhoon Tip]

yeah keep in mind...smear this out more and we're talking virga and hill top flurries... not outside the total realm of possible face-smacks either. 

did you guys see the historic ORD shut-down bomb on the pointless-ranged euro?   the march of madness with this model always kicking the gfs' somehow continues...

[ORH_wxman]

Just now, Typhoon Tip said:

yeah keep in mind...smear this out more and we're talking virga and hill top flurries... not outside the total realm of possible face-smacks either. 

did you guys see the historic ORD shut-down bomb on the pointless-ranged euro?   the march of madness with this model always kicking the gfs' somehow continues...

Actually looked like the 2/2/11 event...including the big CAD signal in New Negland. 

[CoastalWx]

Let's get a Dec 20 2008 CJ going.

[Ginx snewx]

I had 11 on the 19th ,2.5 on the 20th, 5 on the 21st and it snowed the entire time.

[OceanStWx]

9 minutes ago, Typhoon Tip said:

the header indicates that product is for 'NHX' ...i presume to mean the entire hemisphere? 

i ask because i would be surprised to find that is true in quadrature. 

if we slice out just the north american ..sort of "quadraspheric" realm and score it as a subset, i wonder if doesn't score worse compared to the whole: the D 4 - 8 range ( assume to be late middle range).  granularity in the score results (at least intuitively) seems that it must exist.  

hypothetically, the model may be perfect over Japan and only c+ over Madagascar ... the "mad" guy may wonder why everyone's so reliant on the euro.

or not ... just sayn'.  

also, that product doesn't specify how much data is in the running (total results)/n-terms; a point that was central to the original question: ".. ...not sure we have that much data given to the youthfulness of this recent upgrade... ."  if the score is comparing 4 years of data in one product against 18 months of data in the other, i'd caution using that comparison. heh, you'd think who ever is putting those stats together has the scientific foresight not to mix match chi-test but then again ... that product did originate from a government agency so you never know -...  j/k 

i happen to know that since this autumn, the GFS has not performed as badly as it used to from ORD to BOS corridor in the late middle range for significant impact - modeled scenarios. and, as the euro has had more amplitude (and always seems to in that time range in question) that hasn't verified too well, ...i dunno - i warned people not to buy into the euor's wound up torque jobs and keep getting proven right when two cycles later, the depiction abandons the notion for a reason.  it has to do with both a-priori education/wisdom about matters combined with these observations.  yet those darn verifications keep saying Trump won the election - okay...  interesting. 

 

Well I'm pretty sure it is just comparing the model against analysis and scoring, so it shouldn't matter how recent the GFS upgrade was. As for your first point about smaller areas of verification, that may be true, but I don't see any readily available statistics to back that up. EMC seems to focus on hemispheres, tropics, or the PNA region. Similar over at ECMWF.

Who knows, maybe the increases in resolution have pushed the Euro to a point where convection can overwhelm its once more temperate judgement when it comes to low pressure strength? 

[Typhoon Tip]

1 minute ago, ORH_wxman said:

Actually looked like the 2/2/11 event...including the big CAD signal in New Negland. 

your ability to randomly ferret these references out of mind is nothing shy of astounding, bro...  something that's always duly impressed.

i have this ability, but it has to be of the jan 25-27, feb 5-7, dec 9-11, march 11-13, apr 1-2 ... type ilk, with a few personally biased faves thrown in, in order to do so.  

yeah no i'm with you...  You know, one thing i am noticing, if ever there is a trend to lower the gradient in the extended(s) the model that is doing it seems to manufacture one of these corrective bombs almost immediately.  almost like metaphoric to uncorking the proverbial champagne bottle and relieving the potential that is capped by all that compression in the flow. these needling inch to 3" inch jobs don't really do much in the grander thermal engine of the planet; at least not our contribution on this side of the hemisphere. i mean, ha, we probably forget that the reason these storms happen in the first place is because the system on whole is in a constant state of neutralizing the equator sides against the pole. 

but i'm just being sci-fi at the moment... i'm not sure what the total Terran energy budget calculates to in terms of exchange rates in a pattern such as this, when there is 10 or more isopleth packed into about 35 deg of latitude around the Hemisphere.  maybe this is the most efficient way because it the energy is exhausted in kinetic wind power... we'd have to go through the math and f that.

[Typhoon Tip]

3 minutes ago, OceanStWx said:

Well I'm pretty sure it is just comparing the model against analysis and scoring, so it shouldn't matter how recent the GFS upgrade was. As for your first point about smaller areas of verification, that may be true, but I don't see any readily available statistics to back that up. EMC seems to focus on hemispheres, tropics, or the PNA region. Similar over at ECMWF.

Who knows, maybe the increases in resolution have pushed the Euro to a point where convection can overwhelm its once more temperate judgement when it comes to low pressure strength? 

awesome question...  Mike and I (back in the day when he used the forums for pass-time more; Eastern) once speculated similarly of the then ETA ...soon to be NAM then (whatever happens to the WRF idea?  I thought that was an experiment where everyone with the wherewithal ran one then the results were combined - I may not have that quite right) ...

anyway, the idea was that the NAM model is overwhelmed ...almost like incomplete grid point calculations that are allowed to terminate so the processing can gulp down and move on - so to speak.  think 'too much of a good thing', when letting a slightly lower resolution version run out more completely would have errors but they would be more manageable/dependable.  

gee, it's creating more questions for me.  like, the petaflop upgrades in the GFS; does the NAM benefit from that computing power?  an order of magnitude increase in computing power is also wasted if the input data has gaps - i've often wondered how that is sufficed. 

[OceanStWx]

5 minutes ago, Typhoon Tip said:

gee, it's creating more questions for me.  like, the petaflop upgrades in the GFS; does the NAM benefit from that computing power?  an order of magnitude increase in computing power is also wasted if the input data has gaps - i've often wondered how that is sufficed. 

In short, yes. 

[Typhoon Tip]

2 minutes ago, OceanStWx said:

In short, yes. 

hahaha, oh man - hell halth no fury like a forum when the NAM's 60 hour goes from in sh!t to in charge...  

[mreaves]

52 minutes ago, J Paul Gordon said:

Several days of strung out snows with net accumulation would be nice this time of year. Would love to see four days of 4-6 inch snows over one quick hit of 16-24 inches. Not even pretending that either type event is heading our way, though. Just some December fantasizing

 

 

51 minutes ago, CoastalWx said:

 

48 minutes ago, J Paul Gordon said:

I accept the award with due humility and great  pleasure!

 

49 minutes ago, weathafella said:

Turning back a potential 2 footer for 4 days of moderate?  You are hereby excommunicated from weenie nation!

From hero to zero, that didn't take long!

[mahk_webstah]

33 minutes ago, Ginx snewx said:

I had 11 on the 19th ,2.5 on the 20th, 5 on the 21st and it snowed the entire time.

I believe I ended up with 30 inches in a 5 day period during that time.  It was my true intro and first winter in NH.

[codfishsnowman]

I had just under 8 on the 19th, 3 on the 20th and 3 more the 21st, but the snow on the 20th was my favorite, just steady light accumulating snow all day

 

the 19th was okay but most were forecasting a foot here and the 21st was kind of meh but overall it was a nice three days

[CoastalWx]

It's too bad they can't get rid of off hour GFS/GEFS, and put some sort of short range ensemble forecasts that have 1 core with multiple members along with short term models. Just basically allocating bandwidth to help with operational forecasts. 

[CoastalWx]

And stop running the G-Dam SREFs with two cores that make for useless solutions.

[codfishsnowman]

Just now, codfishsnowman said:

I had just under 8 on the 19th, 3 on the 20th and 3 more the 21st, but the snow on the 20th was my favorite, just steady light accumulating snow all day

 

the 19th was okay but most were forecasting a foot here and the 21st was kind of meh but overall it was a nice three days

and there hasn't been a stretch like that since...there were a couple events that produced three days of snow for eastern areas winter 14-15 but that was certainly not observed here in dv

[Typhoon Tip]

i think the euro is interesting at 96 hours.  already ... the 700 and 850 mb RH numbers are both above 70%, while the deep layer mechanics associated to what is better perceived as s/w is still way back ~ 100 W.  

that's pregnant with snow growth potential having that much deep layer moisture should that verify - long duration slow isentropic lifting. hours of post-card light snow could take place well ahead of ...whatever happens there.

[codfishsnowman]

4 minutes ago, Typhoon Tip said:

i think the euro is interesting at 96 hours.  already ... the 700 and 850 mb RH numbers are both above 70%, while the deep layer mechanics associated to what is better perceived as s/w is still way back ~ 100 W.  

that's pregnant with snow growth potential having that much deep layer moisture should that verify - long duration slow isentropic lifting. hours of post-card light snow could take place well ahead of ...whatever happens there.

and that kind of scenario sounds great

[tamarack]

3 hours ago, powderfreak said:

Plenty of action out through day 10 on all models...like a different system every other day.  Lots of SWFE type systems on the 6z GFS through day 10.

That run did have action, though it looked like 4 strikeouts Sunday night thru Thursday.  Maybe 3 Ks (whiffs/near-whiffs) wrapped around a foul ball (Wed. cutter.)  Then a real torch deluge in clown range, stemwinder centered over Plattsburg.  Of course, some of that "action" is run-to-run changes - at least it's not boring.

[dryslot]

19 minutes ago, tamarack said:

That run did have action, though it looked like 4 strikeouts Sunday night thru Thursday.  Maybe 3 Ks (whiffs/near-whiffs) wrapped around a foul ball (Wed. cutter.)  Then a real torch deluge in clown range, stemwinder centered over Plattsburg.  Of course, some of that "action" is run-to-run changes - at least it's not boring.

Was not a big fan of the overnight stuff, Already know what affects a cold pressing high has

[Damage In Tolland]

25 minutes ago, Typhoon Tip said:

i think the euro is interesting at 96 hours.  already ... the 700 and 850 mb RH numbers are both above 70%, while the deep layer mechanics associated to what is better perceived as s/w is still way back ~ 100 W.  

that's pregnant with snow growth potential having that much deep layer moisture should that verify - long duration slow isentropic lifting. hours of post-card light snow could take place well ahead of ...whatever happens there.

Hopefully feet of deep white babies are born 

[ORH_wxman]

34 minutes ago, CoastalWx said:

And stop running the G-Dam SREFs with two cores that make for useless solutions.

Back when they were running it with RSM and ETA members, it was actually reasonably skillful in synoptic winter events...granted this is purely anecdotal since I don't have empirical stats to back it up but since I was forecasting full time back then I feel my memory of it is probably sound. You could actually use them. They weren't perfect of course but they were a tool that you didn't toss in the trash heap before a winter storm like we do now. Seems like all the short range models minus the RGEM have become pigeonholed into being "convection specialists". 

[ORH_wxman]

NAM seems to imply two waves...a round of light snow on Sunday afternoon before what looks like the main show on Monday...and yes, it's clown range on the NAM, but it's before any other guidance is out yet.

[OceanStWx]

2 minutes ago, ORH_wxman said:

Back when they were running it with RSM and ETA members, it was actually reasonably skillful in synoptic winter events...granted this is purely anecdotal since I don't have empirical stats to back it up but since I was forecasting full time back then I feel my memory of it is probably sound. You could actually use them. They weren't perfect of course but they were a tool that you didn't toss in the trash heap before a winter storm like we do now. Seems like all the short range models minus the RGEM have become pigeonholed into being "convection specialists". 

And given that the latest weather forecast improvement bill that hit the senate (and should be passed) talks all about tornadoes and hurricanes, I don't think that it going to change anytime soon. 

Which is odd, because floods, heat, and snow kill far more people per year. 

Interesting how the GFS has almost transitioned to a pure clipper now for the first wave. Strong flow with it (40-50 knots isentropic on 285K) but very shallow slope. The follow up wave has weaker flow (25 knots on 285K) but is a sharper slope right over SNE.

[dryslot]

12z GFS amped up that second wave

[CoastalWx]

GFS more amped. LOL.