moneypitmike Posted November 25, 2014 Share Posted November 25, 2014 Here is a figure from a study on ice crystal growth regimes (Bailey and Hallett 2009). It's interesting to see what the snow growth environment looks like on this mornings 06z GFS, which seems to be in better agreement with the Euro. For ORH at 21z Wed, the greatest lift is forecast to be just above 700 mb (white curve; lowering from ~550 mb at 12z Wed). Temperatures are around -5C in this region which corresponds to the needles/columns for higher ice supersaturation, which is present due to the profile being nearly saturated with respect to liquid. At ALB for the same time, the greatest lift is around 550 mb due to the farther northwest position relative to the coastal low (and thus the maximum frontogenesis occurs at a higher altitude). While omega is not as negative as at ORH, this maximum lift occurs where the temperatures are near -13C. This is where dendritic crystals are favored to grow, again based on the diagram. However, you can see that the dew point is slightly lower than temperature in these regions, meaning that the ice supersaturation is less than at ORH. Therefore, the huge dendrites that might be seen at liquid water saturation will probably not be present. However, the modest-sized dendrites will tend to aggregate more efficiently than needles and those produce a greater proportion of lower density aggregates. This effect by itself will tend to lead to greater snow ratios. Thanks for the lesson--very helpful. Link to comment Share on other sites More sharing options...
CoastalWx Posted November 25, 2014 Share Posted November 25, 2014 What makes you think that when there was what seemed to me a shift (outside of EC and to a lesser degree GFS) eastward of other models last night? There was no eastward shift. The GFS and NAM held serve and the 6z runs ticked NW. I think we are pretty much locked, but wiggles 25 miles one way or another actually mean quite a bit. Link to comment Share on other sites More sharing options...
dryslot Posted November 25, 2014 Share Posted November 25, 2014 I just saw your 5.5"-to-date in your signature. Good chance you'll be riding atop the leader board come Thanksgiving morning. Yeah,We should add another 10" or so,Should make hunting Thurs,Fri and Saturday quite interesting. Link to comment Share on other sites More sharing options...
dryslot Posted November 25, 2014 Share Posted November 25, 2014 Some saw what they really wanted to see happen,But 0z models held other then if you want to say the Ukie went east it did to line up with the rest but still looks like all the other models coming together on a track between ack and the BM Link to comment Share on other sites More sharing options...
CoastalWx Posted November 25, 2014 Share Posted November 25, 2014 Some saw what they really wanted to see happen,But 0z models held other then if you want to say the Ukie went east it did to line up with the rest but still looks like all the other models coming together on a track between ack and the BM Yeah there was no east shift. Don't know what BOX saw. Link to comment Share on other sites More sharing options...
moneypitmike Posted November 25, 2014 Share Posted November 25, 2014 There was no eastward shift. The GFS and NAM held serve and the 6z runs ticked NW. I think we are pretty much locked, but wiggles 25 miles one way or another actually mean quite a bit. Some saw what they really wanted to see happen,But 0z models held other then if you want to say the Ukie went east it did to line up with the rest but still looks like all the other models coming together on a track between ack and the BM Okay--I had read it incorrectly. Link to comment Share on other sites More sharing options...
CT Rain Posted November 25, 2014 Share Posted November 25, 2014 Looking at mid level features it almost looks like there's no 700 mb low... just a frontal zone with strong convergence that sort of lines up across western areas down into NJ. Link to comment Share on other sites More sharing options...
weathafella Posted November 25, 2014 Share Posted November 25, 2014 Some saw what they really wanted to see happen,But 0z models held other then if you want to say the Ukie went east it did to line up with the rest but still looks like all the other models coming together on a track between ack and the BMThis.One thing mentioned by you and others is the para may be euro like in that it seems to be less prone to wild swings which may be useful. The fact that it took till within 72 hours to have the storm however is disconcerting. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted November 25, 2014 Share Posted November 25, 2014 The sfc definitely is colder on the Euro than the 12z run..but the other features are not that different. It still sends sleet pretty far...around ORH at the height of it.So it sounds better for the lower elevations, now hopefully we can work on that ugly sleet south of the pike Link to comment Share on other sites More sharing options...
dryslot Posted November 25, 2014 Share Posted November 25, 2014 You really need to look no further then what the Euro did to see what went on, Other then some noise, I think we have our solution unless modeling is wrong on strength or convection screwing it up one way or the other Link to comment Share on other sites More sharing options...
dryslot Posted November 25, 2014 Share Posted November 25, 2014 This. One thing mentioned by you and others is the para may be euro like in that it seems to be less prone to wild swings which may be useful. The fact that it took till within 72 hours to have the storm however is disconcerting. It was stubborn but made a slow progression west so unless you analyzed each run it was not jump out noticeable Link to comment Share on other sites More sharing options...
moneypitmike Posted November 25, 2014 Share Posted November 25, 2014 Looking at mid level features it almost looks like there's no 700 mb low... just a frontal zone with strong convergence that sort of lines up across western areas down into NJ. Ryan--are you seeing that across models? Would that allow for a more uniform distribution rather than 'jackpot' areas? That will keep everyone in the game (p-type notwithstanding). Meanwhile, with a look to antecedent conditions, temps come down 2.5* since I awoke at 5:00. Miles to go, miles to go. 52.1/46 Link to comment Share on other sites More sharing options...
dryslot Posted November 25, 2014 Share Posted November 25, 2014 Okay--I had read it incorrectly. You're in good seat for this one and will be adding your name to the snow total board as well as others Link to comment Share on other sites More sharing options...
CT Rain Posted November 25, 2014 Share Posted November 25, 2014 Ryan--are you seeing that across models? Would that allow for a more uniform distribution rather than 'jackpot' areas? That will keep everyone in the game (p-type notwithstanding). Meanwhile, with a look to antecedent conditions, temps come down 2.5* since I awoke at 5:00. Miles to go, miles to go. 52.1/46 I think you're in a pretty good area there. Plenty of mid level frontogenesis and a colder profile for you to cash in with. Link to comment Share on other sites More sharing options...
dryslot Posted November 25, 2014 Share Posted November 25, 2014 Today is still going to be torchy,I think it's a step down over the next 24 for cooling down temps,But once Precip starts inland areas should wet bulb down fairly quickly Link to comment Share on other sites More sharing options...
moneypitmike Posted November 25, 2014 Share Posted November 25, 2014 You're in good seat for this one and will be adding your name to the snow total board as well as others Well, right now I'm sitting there with a 0.0" as my official record. Reality has a bit, but I never took measurements on the really minor events. Link to comment Share on other sites More sharing options...
moneypitmike Posted November 25, 2014 Share Posted November 25, 2014 Today is still going to be torchy,I think it's a step down over the next 24 for cooling down temps,But once Precip starts inland areas should wet bulb down fairly quickly That will hurt the initial accumulations. When you think of the Oct. '11 storm, it was cold leading up to the storm so accumulations were able to begin immediately. Even with the air cooling down, I have to think the ground (paved areas?) will retain some of the warmth presented by the last few days of torch. Of course, once accumulation begins, that will be moot. Link to comment Share on other sites More sharing options...
CT Rain Posted November 25, 2014 Share Posted November 25, 2014 That will hurt the initial accumulations. When you think of the Oct. '11 storm, it was cold leading up to the storm so accumulations were able to begin immediately. Even with the air cooling down, I have to think the ground (paved areas?) will retain some of the warmth presented by the last few days of torch. Of course, once accumulation begins, that will be moot. You may lose a few hundreths of liquid to it but nothing major. Link to comment Share on other sites More sharing options...
powderfreak Posted November 25, 2014 Share Posted November 25, 2014 BTV's map... I would be beyond happy with 4-6". Still thinking 2-4" though. Link to comment Share on other sites More sharing options...
CT Rain Posted November 25, 2014 Share Posted November 25, 2014 Here is a figure from a study on ice crystal growth regimes (Bailey and Hallett 2009). It's interesting to see what the snow growth environment looks like on this mornings 06z GFS, which seems to be in better agreement with the Euro. For ORH at 21z Wed, the greatest lift is forecast to be just above 700 mb (white curve; lowering from ~550 mb at 12z Wed). Temperatures are around -5C in this region which corresponds to the needles/columns for higher ice supersaturation, which is present due to the profile being nearly saturated with respect to liquid. korh_06zGFS_26_21z.png At ALB for the same time, the greatest lift is around 550 mb due to the farther northwest position relative to the coastal low (and thus the maximum frontogenesis occurs at a higher altitude). While omega is not as negative as at ORH, this maximum lift occurs where the temperatures are near -13C. This is where dendritic crystals are favored to grow, again based on the diagram. However, you can see that the dew point is slightly lower than temperature in these regions, meaning that the ice supersaturation is less than at ORH. Therefore, the huge dendrites that might be seen at liquid water saturation will probably not be present. However, the modest-sized dendrites will tend to aggregate more efficiently than needles and those produce a greater proportion of lower density aggregates. This effect by itself will tend to lead to greater snow ratios. kalb_06zGFS_26_21.png Nice post - there will be a sweet spot of dendritic growth and down this way it's pretty ugly. I think a lot of people forget that it's not just the fact that dendrites accumulate readily but it's also that ice crystal growth is maximized at -15c so you get a lot more bang for your buck with a given amount of omega in the SGZ as opposed to at say -6c. Link to comment Share on other sites More sharing options...
moneypitmike Posted November 25, 2014 Share Posted November 25, 2014 You may lose a few hundreths of liquid to it but nothing major. I was referring to the whole region, not just mby. I'm not sure if you response was just to my hood. BTV's map... I would be beyond happy with 4-6". Still thinking 2-4" though. StormTotalSnowFcst.png You're worse than I. Lol. 51.9/42 Link to comment Share on other sites More sharing options...
CT Rain Posted November 25, 2014 Share Posted November 25, 2014 I was referring to the whole region, not just mby. I'm not sure if you response was just to my hood. You're worse than I. Lol. 51.9/42 Well there's no question it will be an issue in the valleys and the coastal plain. That's why we've shaved a lot off what you'd expect from a 10:1 kind of event. Lots of red flags for some areas. Pretty good consensus with about 1" of QPF around Hartford but we're only going 3-6" for the city. Link to comment Share on other sites More sharing options...
weathafella Posted November 25, 2014 Share Posted November 25, 2014 Someone is going to smack mpm in the head with all the eeyore crap if they can wade through the snow drifts leading up to his door Thursday. Link to comment Share on other sites More sharing options...
powderfreak Posted November 25, 2014 Share Posted November 25, 2014 You're worse than I. Lol. 51.9/42 Huh? No one is worse than you You can't possibly look at the models and think this spot is where you'd want to be this storm. I'm like 45 minutes south of Canada. I'm in the same boat as the coastal folks except my battle isn't rain vs snow, it's snow vs no precip. I suspect I'll be close in snow to some coastal peeps that struggle with boundary layer temps, in that 3-4" range. GC to Dendrite to Dryslot all the way. Link to comment Share on other sites More sharing options...
wxsniss Posted November 25, 2014 Share Posted November 25, 2014 Re: 0z trends and what BOX saw: I think we all observed and agreed that 0z RGEM and 21z SREFs (and 0z UK) did in fact tick east and colder for eastern SNE, 0z NAM was colder especially for eastern MA with more northern ageostrophic flow and heavy rates, and 0z GFS held. I don't think BOX or anyone here was incorrectly reading the 0z suite per what they wanted. The 6z trend (NAM, GFS, 3z SREFs) is pretty undeniably a tick back west from the 0z suite. As was stated, all little bumps within a tight cluster, but very big differences in outcome between 0z vs. 6z for eastern MA. Link to comment Share on other sites More sharing options...
ORH_wxman Posted November 25, 2014 Author Share Posted November 25, 2014 Someone is going to smack mpm in the head with all the eeyore crap if they can wade through the snow drifts leading up to his door Thursday. Anyone in the interior who is going to get a good event regardless who starts getting a jackpot fetish in this thread worrying about 8" vs 9.7" vs 10.4" is going to suffer my full wrath. Shelter is available in the storm banter thread. Link to comment Share on other sites More sharing options...
moneypitmike Posted November 25, 2014 Share Posted November 25, 2014 Well there's no question it will be an issue in the valleys and the coastal plain. That's why we've shaved a lot off what you'd expect from a 10:1 kind of event. Lots of red flags for some areas. Pretty good consensus with about 1" of QPF around Hartford but we're only going 3-6" for the city. I'd be shocked if Kevin's area doesn't do well. Link to comment Share on other sites More sharing options...
MaineJayhawk Posted November 25, 2014 Share Posted November 25, 2014 GYX map .... less robust than I was expecting/hoping Link to comment Share on other sites More sharing options...
HoarfrostHubb Posted November 25, 2014 Share Posted November 25, 2014 Subdude and WhiteWorldminster will battle it out with HippyDippyValley and MopeyPitMike for the jackpots... Link to comment Share on other sites More sharing options...
dryslot Posted November 25, 2014 Share Posted November 25, 2014 Well, right now I'm sitting there with a 0.0" as my official record. Reality has a bit, but I never took measurements on the really minor events. You should be measuring everything, Get into the habit, If you're a spotter like myself, It is automatic Link to comment Share on other sites More sharing options...
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