ORH_wxman Posted January 25, 2011 Share Posted January 25, 2011 Its remarkable how the 06 and 18Z NAM runs almost always follow the same general biases when they do something unusual...the 18s are often extremely wet and the 06s are often very suppressed and dry...there have been two huge 06z runs inside 48 hours of an event in the last 13 months alone where the NAM whiffed clean up and down the coast on everyone. Its weird, because the off hour runs had been losing those biases quite a bit the last few years....but this winter it seems like we've turned back the clock 5 years and have these bizarre off hour solutions again that don't lead into any type of trend and they snap back at 00z or 12z. Its pretty frustrating. I wonder what is causing them to pull this behavior again. It might just be a fluke that its happening but if it keeps up much longer, there might be a legit reason. Link to comment Share on other sites More sharing options...
ski MRG Posted January 25, 2011 Share Posted January 25, 2011 Right, but expecting it or even hoping for it is an exercise in futility.....he prob still killed me in depth and overall winter appeal that winter, anyway. I'm back to bed. This will be a good one for all I hope.later. Link to comment Share on other sites More sharing options...
Arnold214 Posted January 25, 2011 Share Posted January 25, 2011 Looks like another 06z sh**show by the NCEP models tonight...starting with the NAM. 12z nam probably comes in with something obscene for ORH...probably like 2.25" qpf or something like that. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted January 25, 2011 Share Posted January 25, 2011 12z nam probably comes in with something obscene for ORH...probably like 2.25" qpf or something like that. I was actually thinking that. Night. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted January 25, 2011 Share Posted January 25, 2011 Man, I missed these early morning DISCOs between Will, Eck and I....just like the old days. Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2011 Share Posted January 25, 2011 12z nam probably comes in with something obscene for ORH...probably like 2.25" qpf or something like that. Yeah wouldn't be surprised, lol. Just when you think its completely lost, then it tries to bring it all back in one run and overamps the whole thing and spits out 30" of snow. Pretty hard to go against the Euro and Euro ensembles at this point (which looked almost dead on with the OP run just a while ago)....and the GEFS agree too with maybe a little bit pushed SE, but not by a lot. Pretty amazing that we have models giving your BY literally not a flake from this and then we have the Euro and its ensmebles giving an inch of qpf and GEFS over 0.50". Link to comment Share on other sites More sharing options...
Arnold214 Posted January 25, 2011 Share Posted January 25, 2011 Man, I missed these early morning DISCOs between Will, Eck and I....just like the old days. you can sleep well knowing the ec is giving you like a buck 70. OBSCENE. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted January 25, 2011 Share Posted January 25, 2011 Its weird, because the off hour runs had been losing those biases quite a bit the last few years....but this winter it seems like we've turned back the clock 5 years and have these bizarre off hour solutions again that don't lead into any type of trend and they snap back at 00z or 12z. Its pretty frustrating. I wonder what is causing them to pull this behavior again. It might just be a fluke that its happening but if it keeps up much longer, there might be a legit reason. The NAM has switched to a new "cycling" method lately--dtk explained it nicely to me. Either way--it does seem that this "fluky" run issue may have returned. I am not sure exactly when NCEP implemented this--or even if it has an implications on some of these fluke NAM runs--but I too have noticed more of them lately compared to the last couple years. "I don't have much to add as I'm not even sure I fully understand why the NAM had (still has?) a drift in the large scale (though there are various hypotheses related to the model itself, various DA aspects including bias correction of satellite data, etc.). The NAM domain nowadays is actually quite large (see below)...so lateral boundary conditions shouldn't be an issue for most of the CONUS part of the domain for most of the integration. I think that we've seen pretty big improvement since going to partial cycling instead of allowing the NAM to cycle on itself. I'm not in the meso-group, so I may not have this exactly right (I don't know exactly what what states they use and how far they go back for partial cycling...but basically before each analysis, the NAM is started from a previous GFS state (from 12 hrs ago all fields, not just the boundaries). Then, a series of analyses and forecasts of the NAM are run leading up to the actual initialization time, at which point the full 84 hour forecast is run (the lateral boundary conditions for this are updated using the previous GFS fcst, from 6 hours ago). I think the cycling is 3 hourly leading up to initialization time (in other words, it starts from a GFS forecast, assimilates obs, runs a short NAM forecast, assimilates more obs, runs another short NAM forecast, etc.). This allows the NAM to start from a large scale that is like the GFS, but try to resolve scales / features at its own resolution and consistent with its own dynamics. This essentially cuts off any possible "drift" in the large scale, at least relative to the GFS, since it's forced to do a complete restart from a global state very so often." Link to comment Share on other sites More sharing options...
SnowGoose69 Posted January 25, 2011 Share Posted January 25, 2011 12z nam probably comes in with something obscene for ORH...probably like 2.25" qpf or something like that. As long as the 06Z GFS doesn't do anything wierd I wouldn't worry much....the off hour GFS runs are usually better than the NAM inside 60 hours, most of the bad off hour GFS runs occur outside of that range. Link to comment Share on other sites More sharing options...
earthlight Posted January 25, 2011 Share Posted January 25, 2011 As long as the 06Z GFS doesn't do anything wierd I wouldn't worry much....the off hour GFS runs are usually better than the NAM inside 60 hours, most of the bad off hour GFS runs occur outside of that range. Am I the only one that remembers a night or two before Feb 06 when the NAM and GFS both came in with turds? We had half of weenie nation off the empire state. Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2011 Share Posted January 25, 2011 The NAM has switched to a new "cycling" method lately--dtk explained it nicely to me. Either way--it does seem that this "fluky" run issue may have returned. I am not sure exactly when NCEP implemented this--or even if it has an implications on some of these fluke NAM runs--but I too have noticed more of them lately compared to the last couple years. "I don't have much to add as I'm not even sure I fully understand why the NAM had (still has?) a drift in the large scale (though there are various hypotheses related to the model itself, various DA aspects including bias correction of satellite data, etc.). The NAM domain nowadays is actually quite large (see below)...so lateral boundary conditions shouldn't be an issue for most of the CONUS part of the domain for most of the integration. I think that we've seen pretty big improvement since going to partial cycling instead of allowing the NAM to cycle on itself. I'm not in the meso-group, so I may not have this exactly right (I don't know exactly what what states they use and how far they go back for partial cycling...but basically before each analysis, the NAM is started from a previous GFS state (from 12 hrs ago all fields, not just the boundaries). Then, a series of analyses and forecasts of the NAM are run leading up to the actual initialization time, at which point the full 84 hour forecast is run (the lateral boundary conditions for this are updated using the previous GFS fcst, from 6 hours ago). I think the cycling is 3 hourly leading up to initialization time (in other words, it starts from a GFS forecast, assimilates obs, runs a short NAM forecast, assimilates more obs, runs another short NAM forecast, etc.). This allows the NAM to start from a large scale that is like the GFS, but try to resolve scales / features at its own resolution and consistent with its own dynamics. This essentially cuts off any possible "drift" in the large scale, at least relative to the GFS, since it's forced to do a complete restart from a global state very so often." Thanks for the explanation. I wouldn't mind if the off hour flukes returned a bit if it improved the 12z and 00z runs. We really don't have a huge need for 06z and 18z runs as it is. We end up spending more time on staring at the model output than we do trying to analyze the synoptic and mesoscale setup with so many model runs. Link to comment Share on other sites More sharing options...
Arnold214 Posted January 25, 2011 Share Posted January 25, 2011 Yeah wouldn't be surprised, lol. Just when you think its completely lost, then it tries to bring it all back in one run and overamps the whole thing and spits out 30" of snow. Pretty hard to go against the Euro and Euro ensembles at this point (which looked almost dead on with the OP run just a while ago)....and the GEFS agree too with maybe a little bit pushed SE, but not by a lot. Pretty amazing that we have models giving your BY literally not a flake from this and then we have the Euro and its ensmebles giving an inch of qpf and GEFS over 0.50". My money is with the ecmwf...maybe a tick SE. Based on the current ec's mid level features I think you jackpot verbatim (knock on wood). Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2011 Share Posted January 25, 2011 Am I the only one that remembers a night or two before Feb 06 when the NAM and GFS both came in with turds? We had half of weenie nation off the empire state. I remember the 06z ETA run...it was less than 24h before the start of the storm. It gave me a trace I think. Link to comment Share on other sites More sharing options...
earthlight Posted January 25, 2011 Share Posted January 25, 2011 I remember the 06z ETA run...it was less than 24h before the start of the storm. It gave me a trace I think. Oh right, it was the ETA at that point...wasn't it run under "NAM" though? Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2011 Share Posted January 25, 2011 My money is with the ecmwf...maybe a tick SE. Based on the current ec's mid level features I think you jackpot verbatim (knock on wood). Yeah it doesn't get much better looking in the MLs and ULs for here than the ECMWF has it....which is why I'm expecting a little shift. Its "too perfect". But regardless, I feel pretty good here. I'll be happy with a large storm, I don't need to jackpot as nice as it would be. A bit of a nastier forecast up there, but I have an inkling you guys will get close to what the ECM says. We still have 48h to go and as long as there isn't any disastrous misinterpretation by the models in the ULs, we tend to see these juicy moisture-laden systems give a little tick NW in the qpf/deformation as we get closer even if the main track stays the same. Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2011 Share Posted January 25, 2011 Oh right, it was the ETA at that point...wasn't it run under "NAM" though? Yes, it was the NAM-ETA...now its the NAM-WRF...it was actually the final big east coast storm the OP NAM was run under the ETA, it was changed just a month or two later. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted January 25, 2011 Share Posted January 25, 2011 Thanks for the explanation. I wouldn't mind if the off hour flukes returned a bit if it improved the 12z and 00z runs. We really don't have a huge need for 06z and 18z runs as it is. We end up spending more time on staring at the model output than we do trying to analyze the synoptic and mesoscale setup with so many model runs. Yeah agreed. I typically consider the off-hour runs as an "ensemble" member--typically the NAM gets the least consideration unless it seems it is catching on to something. Off-hour runs will likely be around for a while though as NCEP has no plans to implement computationally expensive and time-consuming 4Dvar data assimilation systems like Environment Canada and ECMWF. According to dtk the modeling expert--the GFS will soon be implementing a "hybrid" data assimilation system based of ensemble Kalman Filtering AND 4Dvar--but I don't think it will get rid of the off-hour runs. Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2011 Share Posted January 25, 2011 Yeah agreed. I typically consider the off-hour runs as an "ensemble" member--typically the NAM gets the least consideration unless it seems it is catching on to something. Off-hour runs will likely be around for a while though as NCEP has no plans to implement computationally expensive and time-consuming 4Dvar data assimilation systems like Environment Canada and ECMWF. According to dtk the modeling expert--the GFS will soon be implementing a "hybrid" data assimilation system based of ensemble Kalman Filtering AND 4Dvar--but I don't think it will get rid of the off-hour runs. Yeah there are very select setups where the NAM will perform better in the 48-72h range over the global models...the Jan 12th storm was one of them because of how compact all the features were and there was a ton of convection with it to boot right near the center...but those are clearly the exceptions rather than the rule. This system is much larger in circulation and coverage which is kind of the opposite of the NAM's wheelhouse...too many ways for it to screw up the large circulation with little meso-vorticies and convective feedback too far form the center. Who knows for sure though...maybe the NAM will be right this time too, but I have little reason to believe it because of what I stated above...just not its typical setup where it does well. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted January 25, 2011 Share Posted January 25, 2011 Yeah there are very select setups where the NAM will perform better in the 48-72h range over the global models...the Jan 12th storm was one of them because of how compact all the features were and there was a ton of convection with it to boot right near the center...but those are clearly the exceptions rather than the rule. This system is much larger in circulation and coverage which is kind of the opposite of the NAM's wheelhouse...too many ways for it to screw up the large circulation with little meso-vorticies and convective feedback too far form the center. Who knows for sure though...maybe the NAM will be right this time too, but I have little reason to believe it because of what I stated above...just not its typical setup where it does well. Its very easy to pick out where the NAM goes wrong, although it does have mistakes before 42 hours it really loses things right at 42...the 500 low is over central NC and the surface low should be east of ORF somewhere...you can see evidence the NAM wants to put it there with the deformation signature over VA and the fact that area is dead center within its lowest pressure contour but it tries to start the double low fiasco at that point. Link to comment Share on other sites More sharing options...
Arnold214 Posted January 25, 2011 Share Posted January 25, 2011 Yeah there are very select setups where the NAM will perform better in the 48-72h range over the global models...the Jan 12th storm was one of them because of how compact all the features were and there was a ton of convection with it to boot right near the center...but those are clearly the exceptions rather than the rule. This system is much larger in circulation and coverage which is kind of the opposite of the NAM's wheelhouse...too many ways for it to screw up the large circulation with little meso-vorticies and convective feedback too far form the center. Who knows for sure though...maybe the NAM will be right this time too, but I have little reason to believe it because of what I stated above...just not its typical setup where it does well. It's hard to believe the ec and ec ensembles lay an egg at this point especially since they are in good agreement. The gfs is on the right track...but it's solution seemed a little funky to me...hopefully it can smooth out the wrinkles today. Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2011 Share Posted January 25, 2011 It's hard to believe the ec and ec ensembles lay an egg at this point especially since they are in good agreement. The gfs is on the right track...but it's solution seemed a little funky to me...hopefully it can smooth out the wrinkles today. Yeah especially with how consistent they've been. Its not like they just latched onto this solution at 00z, they've been doing this for 2-3 days now. GFS looked like it was still slightly disjointed with the warm conveyor stuff and the ULL-induced CCB. They'll probably be disjointed early on down south, but I have a hard time believing they ride the coast the whole way as two separate entities. BTW, I have the most perfect dendrites falling outside with a temp of 5F, lol. Guess thats what happens when aloft has warmer than near ground in an airmass this cold. Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2011 Share Posted January 25, 2011 BOX has issued a winter storm watch for all zones outside the Cape and Islands. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted January 25, 2011 Share Posted January 25, 2011 The RGEM does something wierd as well at 06Z....orienting the QPF field at 48 hours in a WSW-ENE direction instead of the classic SSW-NNE...it seems both the NAM and RGEM are having convective and or issues regarding wanting to pop a second low center. Link to comment Share on other sites More sharing options...
ORH_wxman Posted January 25, 2011 Share Posted January 25, 2011 Looks like the 06z GFS completed the nightly 06z SE tick. I think that's 3 06z runs in a row where they go SE. We'll have to see if its actually serious this time or if it just goes back again at 12z. Link to comment Share on other sites More sharing options...
Mr Torchey Posted January 25, 2011 Share Posted January 25, 2011 wow most guidance goes well se overnight (except the euro), they obviously see something, I wonder if its a little more robust confluence in the wake of this dying clipper. Upton has no watches up while mt holly to the sw and box hoist them, is OKX going to once again play the right hand? Link to comment Share on other sites More sharing options...
Damage In Tolland Posted January 25, 2011 Share Posted January 25, 2011 Well after seeing everything this morning..and the Euro holding serve..I think 12-18 for all of interior SNE is a good call with lollis to 22-24 where banding sets up longer Link to comment Share on other sites More sharing options...
grinch1989 Posted January 25, 2011 Share Posted January 25, 2011 Upton goes WSW away from the coast for 6-12" Link to comment Share on other sites More sharing options...
Damage In Tolland Posted January 25, 2011 Share Posted January 25, 2011 I can't believe it actually phased it!!! Best run yet!!! OMFGOMFGOMFG Link to comment Share on other sites More sharing options...
Damage In Tolland Posted January 25, 2011 Share Posted January 25, 2011 Everyone along and SE of a IZG-CON-PSF line gets over 1" of qpf Everyone along and SE of a KGAY-ORH-TOL line gets > 1.50" of qpf. Chuck em low chuck em high..chuck a foot long right into Eksters eye!! Link to comment Share on other sites More sharing options...
moneypitmike Posted January 25, 2011 Share Posted January 25, 2011 Looks like the 06z GFS completed the nightly 06z SE tick. I think that's 3 06z runs in a row where they go SE. We'll have to see if its actually serious this time or if it just goes back again at 12z. I get .01" from both the NAM and GFS 06z runs. I have never been so in the EC camp, even if it's not showing a blockbuster. Looks like I picked up an inch overnight, but appears the bulk of the returns upstream will pass to my south. 3.6/-1 Link to comment Share on other sites More sharing options...
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