whiteout Posted December 17, 2010 Share Posted December 17, 2010 48 looks flatter. Started off well but its meh now Link to comment Share on other sites More sharing options...
mitchnick Posted December 17, 2010 Share Posted December 17, 2010 gone at 48. was hoping it was a sign of a more organized, stronger system... actually, at 60 hrs the Euro map is not as diff as I thought it would look, but euro def better Link to comment Share on other sites More sharing options...
baroclinic_instability Posted December 17, 2010 Share Posted December 17, 2010 gone at 48. was hoping it was a sign of a more organized, stronger system... Gone? I don't think it is over yet. Back end upper tropospheric wave looks much better on this run. Still has potential. Link to comment Share on other sites More sharing options...
PhineasC Posted December 17, 2010 Share Posted December 17, 2010 It won't repeat the Euro, but a big move from 18Z. Link to comment Share on other sites More sharing options...
pojrzsho Posted December 17, 2010 Share Posted December 17, 2010 Slower and bringing rain to Eastern NC at 54, decently further west than 18z 60 for sure Link to comment Share on other sites More sharing options...
Amped Posted December 17, 2010 Share Posted December 17, 2010 gone at 48. was hoping it was a sign of a more organized, stronger system... Northern Stream energy kills it and forms a new low further NE. Link to comment Share on other sites More sharing options...
LakeEffectKing Posted December 17, 2010 Share Posted December 17, 2010 gone at 48. was hoping it was a sign of a more organized, stronger system... Well the pressure field still implies it's dropping, just the wrong contour interval!! Link to comment Share on other sites More sharing options...
baroclinic_instability Posted December 17, 2010 Share Posted December 17, 2010 This NAM run has a far more impressive upper level jet coupling. I think this will end up a lot better than 18Z. Link to comment Share on other sites More sharing options...
Joe4alb Posted December 17, 2010 Share Posted December 17, 2010 This NAM run has a far more impressive upper level jet coupling. I think this will end up a lot better than 18Z. agreed, nice vortmax coming into the base of the trough at 54hrs, i think that will really allow this thing to kick negative after 66hrs. Link to comment Share on other sites More sharing options...
derecho Posted December 17, 2010 Share Posted December 17, 2010 Miss at 60 for mid atlantic. Link to comment Share on other sites More sharing options...
ohleary Posted December 17, 2010 Share Posted December 17, 2010 Miss at 60 for mid atlantic. Where are you looking? Link to comment Share on other sites More sharing options...
psuhoffman Posted December 17, 2010 Share Posted December 17, 2010 This NAM run has a far more impressive upper level jet coupling. I think this will end up a lot better than 18Z. I dont know...I agree it looks a LOT better, especially at upper levels, but it would almost have to go ridiculously negative and back in from where it is to make any difference for DC, Baltimore, and Philly. Link to comment Share on other sites More sharing options...
Paweatherguy1 Posted December 17, 2010 Share Posted December 17, 2010 I have read on here multiple times that past 48 the NAM is pretty worthless...or at least not that great of a model. Is it possible, considering all the noted changes for the better up till 42, that this is just outside of the NAM's good range, and that explains it falling apart at that point? Link to comment Share on other sites More sharing options...
pojrzsho Posted December 17, 2010 Share Posted December 17, 2010 It is a miss at 60, but better than 18, for NAM improvement is key Link to comment Share on other sites More sharing options...
EasternUSWX Posted December 17, 2010 Share Posted December 17, 2010 Much better at upper levels is what we can take from this run. Moving on to GFS and hoping for better results. Link to comment Share on other sites More sharing options...
PhineasC Posted December 17, 2010 Share Posted December 17, 2010 Started out looking good but stunk post 48HR, at least south of NYC. Link to comment Share on other sites More sharing options...
LocoAko Posted December 17, 2010 Author Share Posted December 17, 2010 I have read on here multiple times that past 48 the NAM is pretty worthless...or at least not that great of a model. Is it possible, considering all the noted changes for the better up till 42, that this is just outside of the NAM's good range, and that explains it falling apart at that point? Not really. All models get progressively worse as you go off into the future, including the NAM. Its accuracy doesn't just suddenly drop off significantly after a certain hour. Link to comment Share on other sites More sharing options...
pojrzsho Posted December 17, 2010 Share Posted December 17, 2010 MUCH better low placement at 66, bringing snow to far eastern Md, far ne Va, De, and just touching Se NJ shore......BIG difference from 72 18Z Link to comment Share on other sites More sharing options...
weathervswife Posted December 17, 2010 Share Posted December 17, 2010 NAM has had a HUGE south bias with these clippers only to snap back around 36 hours or so. I wonder if that might be in play here as well. Link to comment Share on other sites More sharing options...
Analog96 Posted December 17, 2010 Share Posted December 17, 2010 Not really. All models get progressively worse as you go off into the future, including the NAM. Its accuracy doesn't just suddenly drop off significantly after a certain hour. This isn't very true. The GFS goes out to 384 hours, so we should expect half of a model's run to USUALLY be fairly accurate. With the GFS, that would take us to 192, which is an interesting number, because that's where truncation occurs. With the NAM, the halfway point would be 42. I know the NAM doesn't truncate, but normally when you get more than halfway out in a model's run, the accuracy begins to decline sharply, almost like your car's gas gauge (on the older cars at least), when it gets near half. Link to comment Share on other sites More sharing options...
Porsche Posted December 17, 2010 Share Posted December 17, 2010 @ 60hr snow breaking out in MD/DE.. nothing at 18z Grabbed this from the NE thread Link to comment Share on other sites More sharing options...
PhineasC Posted December 17, 2010 Share Posted December 17, 2010 Strange looking surface presentation at 66HR. Link to comment Share on other sites More sharing options...
Analog96 Posted December 17, 2010 Share Posted December 17, 2010 MUCH better low placement at 66, bringing snow to far eastern Md, far ne Va, De, and just touching Se NJ shore......BIG difference from 72 18Z Very true. I know one means it's cloudy and the other means mostly sunny, but the results are VERY different. One run ago, the NAM was a miss by a LOT. This one is a near-miss. One more run with the same trend is a hit! Link to comment Share on other sites More sharing options...
mitchnick Posted December 17, 2010 Share Posted December 17, 2010 Grabbed this from the NE thread that's radar, but this is what has actually fallen after 66 hrs Link to comment Share on other sites More sharing options...
jm1220 Posted December 17, 2010 Share Posted December 17, 2010 Looks yet again like mystery vort energy kicks off another low and thunderstorm activity south of the Cape Hatteras low and robs from it. This would probably be a more impressive solution without those mystery vortmaxes over the Atlantic. The jet and energy overall look much more impressive this run than last. Link to comment Share on other sites More sharing options...
Analog96 Posted December 17, 2010 Share Posted December 17, 2010 Grabbed this from the NE thread Depends on which way that moves. If it backs in, many areas get a good snow. Even if it goes straight North, many areas get accumulating snows, and RI/SE Mass get nailed. Link to comment Share on other sites More sharing options...
LocoAko Posted December 17, 2010 Author Share Posted December 17, 2010 This isn't very true. The GFS goes out to 384 hours, so we should expect half of a model's run to USUALLY be fairly accurate. With the GFS, that would take us to 192, which is an interesting number, because that's where truncation occurs. With the NAM, the halfway point would be 42. I know the NAM doesn't truncate, but normally when you get more than halfway out in a model's run, the accuracy begins to decline sharply, almost like your car's gas gauge (on the older cars at least), when it gets near half. Well yeah, I wasn't arguing that it decreases linearly the entire time the model runs. Rather, there is no given "hour" where it suddenly becomes terribly inaccurate. Link to comment Share on other sites More sharing options...
Analog96 Posted December 17, 2010 Share Posted December 17, 2010 Looks yet again like mystery vort energy kicks off another low and thunderstorm activity south of the Cape Hatteras low and robs from it. This would probably be a more impressive solution without those mystery vortmaxes over the Atlantic. The jet and energy overall look much more impressive this run than last. Convective feedback? Link to comment Share on other sites More sharing options...
mitchnick Posted December 17, 2010 Share Posted December 17, 2010 Strange looking surface presentation at 66HR. its out of its effective range I'm not saying that as an excuse, its just that 66 hr NAM progs never materialize any more than random luck of computers Link to comment Share on other sites More sharing options...
Analog96 Posted December 17, 2010 Share Posted December 17, 2010 Well yeah, I wasn't arguing that it decreases linearly the entire time the model runs. Rather, there is no given "hour" where it suddenly becomes terribly inaccurate. Use the halfway point. It generally works. For the old NGM, that would give it about 24 hr. lol Link to comment Share on other sites More sharing options...
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