high risk Posted March 13, 2017 Share Posted March 13, 2017 4 minutes ago, Yeoman said: Sorry - GFS-WRF out of Stony Brook Thanks for clarifying. That's the ARW version of the WRF, run with GFS initial and boundary conditions. Link to comment Share on other sites More sharing options...
yoda Posted March 13, 2017 Share Posted March 13, 2017 1 minute ago, Buddy1987 said: Watch the NAM again. 500 is digging again on the 0z and the southern energy is significantly more west than the 18z position at hr 12 0z Thats bad news, right? Link to comment Share on other sites More sharing options...
Buddy1987 Posted March 13, 2017 Share Posted March 13, 2017 Just now, yoda said: Thats bad news, right? I guess it would be better for me lol. Link to comment Share on other sites More sharing options...
Amped Posted March 13, 2017 Share Posted March 13, 2017 ARW pulling a march 93, low tracks over NYC then up the ct river while NH and ME get dryslotted. Link to comment Share on other sites More sharing options...
stormtracker Posted March 13, 2017 Author Share Posted March 13, 2017 1 minute ago, yoda said: Thats bad news, right? For us, it likely would be, but I don't see that much difference so far Link to comment Share on other sites More sharing options...
high risk Posted March 13, 2017 Share Posted March 13, 2017 1 minute ago, eurojosh said: Thanks, I'm learning a lot from this. So what do you do when the tracks are different for the global vs regional models? For example, if we compare the 18z GFS and NAM at 36 hrs, the NAM has the LP further offshore, but despite this, has warmer 850s approaching DC. So, if we take the GFS track, but the NAM thermals, we get even warmer temps near DC. OTOH, if the NAM's thermals depend on its track, why would we use it at all when the track is different? If the tracks are different, I'd probably lean towards the track of the GFS, but I might adjust the snow/mix line further northwest. But how much to do so is tricky. My overall point is that I would hope that we finally get some track/precip agreement with the 00z cycle. Once we have it, we can give a lot more weight to the thermal profiles of the regional and hi-res models. Of course, if synoptic differences remain, then it's back to the drawing board...... Link to comment Share on other sites More sharing options...
eurojosh Posted March 13, 2017 Share Posted March 13, 2017 SLP MUCH further north at 26 hours - looks more like an early phase. Link to comment Share on other sites More sharing options...
Deck Pic Posted March 13, 2017 Share Posted March 13, 2017 Congrats Morgantown Link to comment Share on other sites More sharing options...
osfan24 Posted March 13, 2017 Share Posted March 13, 2017 Just by looking at the water vapor, I think adjustments south and west with the dig will continue to happen. On water vapor, it looks like it's going to dig farther south and west. Almost like it's heading for Texas. Link to comment Share on other sites More sharing options...
BTRWx Posted March 13, 2017 Share Posted March 13, 2017 5 minutes ago, eurojosh said: SLP MUCH further north at 26 hours - looks more like an early phase. The op NAM's low resolution is being outperformed by more models every year! Link to comment Share on other sites More sharing options...
high risk Posted March 13, 2017 Share Posted March 13, 2017 8 minutes ago, Bob Chill said: Really appreciate the insight and pointing out performance with the NC storm earlier this year. Honestly, I'm surprised the GFS pretty much makes it an all snow storm for the majority of our region. I've been looking at it like having wiggle room because I fully expect to mix at some point. Places further east are a near certainty. I'm just hoping to minimize the loss of precip to something other than snow. I made a post earlier today saying that regardless of what models are spitting out, past history tells us that the likelyhood of mixing in the typical areas is very high with this type of storm. There's going to be strong atlantic fetch at the surface and midlevels for a time while the pivot happens. My guess is the WAA part with southerly flow will be all snow for most everyone. Midlevels are really good leading in an it's really cold right now leading in. Once radar takes on that strong east-west component I'm sure the CC panels on radar are going to show the classic sleet line bearing down on us. How far east it gets before the pivot is anyones guess. My guess is it makes it to my house. Hopefully it's short lived before high ratio CCB/deform kicks in. Bob, I fully agree that climo argues against an all-snow event for you in southern Montgomery and probably for me too in southeast Howard. And I agree with your call on the initial WAA thump of snow, a few hours of mix, and then back to snow in the deformation band. The 18z NAM 3 km parallel nest shows this idea pretty well, although it's sleety for DC Metro for a longer period of time than I'd want to see. The 3km NAM is a significantly upgraded version of the NAM nest that statistically and anecdotally has performed very well this winter, although I have admittedly seen it be a bit too aggressive with the warm layers in winter storms. It's supposed to become operational later this week. Link to comment Share on other sites More sharing options...
eurojosh Posted March 13, 2017 Share Posted March 13, 2017 Link to comment Share on other sites More sharing options...
Deck Pic Posted March 13, 2017 Share Posted March 13, 2017 Awesome..0.4" of light rain through 7 am Link to comment Share on other sites More sharing options...
stormtracker Posted March 13, 2017 Author Share Posted March 13, 2017 Yeah, pushes the 850 line back toward Frederick county line in MD this run. Hopefully it's the NAM being the NAM, but we're in it's supposed wheelhouse now, so I dunno. Hopefully GFS stays steady Link to comment Share on other sites More sharing options...
Fozz Posted March 13, 2017 Share Posted March 13, 2017 29 minutes ago, Warm Nose said: North and West of 95 - all snow. East and south of 95 - mixing. Pretty safe bet around here. I'm north and west of I-95, but I'm definitely expecting at least some mixing, perhaps several hours of sleet. There's a real possibility of a sneaky warm layer making its way past I-95 into places like Cockeysville and Rockville, and I can recall many examples of mixing occurring when it seemed like we'd be all snow. This is the perfect setup for more of that, and that's the difference between Cockeysville and Parkton, or Rockville and Damascus. I don't think the mixing will ruin the storm in places just north and west of the fall line, but it's a good idea to be prepared for some pings. Link to comment Share on other sites More sharing options...
osfan24 Posted March 13, 2017 Share Posted March 13, 2017 Given the low position, why in the world is there so much warm air? It looks east of what I expected it to be. Link to comment Share on other sites More sharing options...
Deck Pic Posted March 13, 2017 Share Posted March 13, 2017 2 minutes ago, stormtracker said: Yeah, pushes the 850 line back toward Frederick county line in MD this run. Hopefully it's the NAM being the NAM, but we're in it's supposed wheelhouse now, so I dunno. Hopefully GFS stays steady It's a terrible model for east coast storms. Full stop. Link to comment Share on other sites More sharing options...
nj2va Posted March 13, 2017 Share Posted March 13, 2017 1 minute ago, stormtracker said: Yeah, pushes the 850 line back toward Frederick county line in MD this run. Hopefully it's the NAM being the NAM, but we're in it's supposed wheelhouse now, so I dunno. Hopefully GFS stays steady Definitely concerning since we're 24 hours out. Though, I'm interested in the parallel versions to come out to see what the upgraded versions look like. I know we're going to mix but if this current version of the NAM is accurate, it'd be a disaster here. Link to comment Share on other sites More sharing options...
EB89 Posted March 13, 2017 Share Posted March 13, 2017 CFI issues? Someone more experienced care to weigh in? The low is jumping all over the place on the 12k. Link to comment Share on other sites More sharing options...
Interstate Posted March 13, 2017 Share Posted March 13, 2017 1 minute ago, nj2va said: Definitely concerning since we're 24 hours out. Though, I'm interested in the parallel versions to come out to see what the upgraded versions look like. I know we're going to mix but if this current version of the NAM is accurate, it'd be a disaster here. I could see a couch being burned in college park Link to comment Share on other sites More sharing options...
DCWeatherGuy Posted March 13, 2017 Share Posted March 13, 2017 38 minutes ago, dallen7908 said: Was comparing the 18Z GFS and 12Z Euro for DCA Both show an 8 PM start and ~0.1, 0.15, and 0.2" of QPF between 8-11 PM , 11 PM to 2 AM, and 2-5 AM; GFS 850 hPa temperatures decrease from -2 to -4 during that period while EURO 850 hPa temperatures increase from -3 to 1. GFS surface temperatures fall from 33 to 30 while Euro surface temperatures hover around 34/35. From 5 AM to 11 AM the GFS continues to show moderate snow with QPF values of 0.2 and 0.2 (~ 1 1/2 inches of snow per hour if we go with an 8 to 1 ratio); Surface temperatures rise slowly from 30 to 32. From 5 AM to 11 AM the Euro shows heavy precipitation with QPF values of 0.36 and 0.27. 850 temperatures plunge during this period of heavy precipitation and are -4.5 by 11 AM; surface temperatures decrease slightly from 34/35 to 33/34. Both models show intermittent light snow /flurries through the afternoon into the late evening with post-11 AM accumulations of ~1". Does anyone who knows such things care to explain to us weenies what is driving this thermal split in the models? It's interesting to me that the two models start at essentially the same place at the onset of the storm (-2/3C) but then go in such different directions. Seems to suggest that they're not disagreeing about the prexisting conditions when the storm arrives, but something about the way in which this all comes together. I hear the talk of the GFS possibly overlooking (or, at least, understating) a warm layer intrusion, but would that explain both the 850s and surface temp differences emerging in the two solutions? Or is it something else? Link to comment Share on other sites More sharing options...
clskinsfan Posted March 13, 2017 Share Posted March 13, 2017 FWIW. The 12K is much better for everyone. And similar to Euro really. Link to comment Share on other sites More sharing options...
Maestrobjwa Posted March 13, 2017 Share Posted March 13, 2017 3 minutes ago, eurojosh said: And Baltimore City is also doing the cake walk next to the line...eh, we'll just have to take what we can get! (But I think I-95's odds of hitting a double-digit snowfall total has diminished somewhat since yesterday) Link to comment Share on other sites More sharing options...
eurojosh Posted March 13, 2017 Share Posted March 13, 2017 Just now, clskinsfan said: FWIW. The 12K is much better for everyone. And similar to Euro really. For everyone where? Shenandoah? Link to comment Share on other sites More sharing options...
stormtracker Posted March 13, 2017 Author Share Posted March 13, 2017 There are 568 versions of the NAM..which is the para? 12k? Link to comment Share on other sites More sharing options...
cae Posted March 13, 2017 Share Posted March 13, 2017 1 hour ago, leesburg 04 said: DTs says GFS has been terribly inconsistent The GFS and UKMET have been the most consistent. The GFS hasn't varied much for our region since about 12z Thursday. It has been a little less consistent up north, for which the UKMET probably gets the edge. Regarding the other discussion of how to weigh the globals vs. regionals, I think it depends on which models you're talking about. The RGEM is highly correlated with the GGEM and will usually closely follow the GGEM's track. At this range, I start giving the RGEM much higher weight than the GGEM, as the RGEM is similar to the GGEM and will pick up on things that the relatively low-resolution GGEM might miss. At this point it might be even better to go with the high-res RGEM, which is stll being developed and is intended to replace the RGEM some day. The NAM vs GFS is trickier, as they can give very different results. Because they're less correlated, it's not like the NAM effectively replaces the GFS in my mental ensemble. Rather I gradually give it more weight until it's treated as something more like a peer. Link to comment Share on other sites More sharing options...
clskinsfan Posted March 13, 2017 Share Posted March 13, 2017 Just now, eurojosh said: For everyone where? Shenandoah? It doesnt push the 850's as far west as the old NAM. Still a lot of mixing. But the track and evolution look a lot like the Euro. Link to comment Share on other sites More sharing options...
BTRWx Posted March 13, 2017 Share Posted March 13, 2017 Just now, stormtracker said: There are 568 versions of the NAM..which is the para? 12k? Good question! Are there two para NAMs? Link to comment Share on other sites More sharing options...
nj2va Posted March 13, 2017 Share Posted March 13, 2017 1 minute ago, stormtracker said: There are 568 versions of the NAM..which is the para? 12k? There's a 12k and parallel 12k. And a 4K and a parallel 4K (aka 3k). I think. Link to comment Share on other sites More sharing options...
cae Posted March 13, 2017 Share Posted March 13, 2017 Just now, BTRWx said: Good question! Are there two para NAMs? The NAM 3k is the high-res nest for the para NAM. It has reportedly been doing well. Link to comment Share on other sites More sharing options...
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