ace0927 Posted December 31, 2013 Share Posted December 31, 2013 The 12z GFSx has very decent snow totals for NYC http://www.nws.noaa.gov/cgi-bin/mos/getmex.pl?sta=KACY&sta=KEWR&sta=KNYC&sta=KJFK&sta=KLGA yeah....thats a BIG snowfall. Up from 0Z Link to comment Share on other sites More sharing options...
PB GFI Posted December 31, 2013 Share Posted December 31, 2013 beggars can never be choosers.... Would like to see Soundings at 72 hrs , as the whole column collapses . Link to comment Share on other sites More sharing options...
IntenseBlizzard2014 Posted December 31, 2013 Share Posted December 31, 2013 yeah....thats a BIG snowfall. Up from 0Z Did I see 10" of snow for LGA? I'm probably reading it wrong. Link to comment Share on other sites More sharing options...
ace0927 Posted December 31, 2013 Share Posted December 31, 2013 Would like to see Soundings at 72 hrs , as the whole column collapses . here you go: Link to comment Share on other sites More sharing options...
ace0927 Posted December 31, 2013 Share Posted December 31, 2013 Did I see 10" of snow for LGA? I'm probably reading it wrong. what you are seeing is a 2-4" followed by a 6-8"....( 2 at 60hrs and 8 at 84hrs) Link to comment Share on other sites More sharing options...
SACRUS Posted December 31, 2013 Share Posted December 31, 2013 Summary of 12z Guidance NJ/NYC/LI (generally least to most SW to NE) NAM: 0.10 - 0.25 GFS: 0.25 - 0.50 GGEM: 0.05 - 0.20 ECM: 0.25 - 0.50 With that NE-NJ/NYC/LI : 3 - 6 CNJ: 2- 5 Link to comment Share on other sites More sharing options...
LocoAko Posted December 31, 2013 Share Posted December 31, 2013 much appreciated Loco The NAM had really diffuse, light lift through most of the column and didn't make a great case for a demonstrative example, so I'm looking at the 12Z GFS for KEWR at 60 hours (7PM Thursday). Here's your traditional Skew-T, with omega (upward vertical motion) plotted in the thin white line. On the temperature line, the dendritic snow growth region is highlighted in yellow (between -12C and -18C). You can see here there is lift occurring in many different temperature regions. The time series data is a bit easier to see this on: This plot is kind of busy and hard to look at, but it shows temperature (gold lines), omega (red - UVV, blue - DVM), the dendritic snow growth region outlined in purple/yellow, and the shading shows the saturation with respect to ice. The vertical line is the 60 h forecast. You can once again see lift through a very broad layer of the atmosphere, including in the snow growth region (where supersaturation exists), but also above and below it. The maximal lift occurs after 00Z Friday and is maximized above the snow growth region. Here it is saturated and around -24C to -30C. The secondary maxima occurs in the -6C to -10C region. Forecasting snow ratios is tough and definitely not my forte, but based on these model runs at least I'd expect a wide range of crystal types given the depth of the (super)saturation and lift, the point being beautiful 20:1 ratios will likely not be the norm here, in accordance with the graph forky posted. Edited to add: As for the 700 hPa level being the source region, you can see here that the dendritic snow growth region actually descends from 600 hPa down to 800-900 hPa as the atmospheric profile becomes much colder with the storm's progression. The strongest lift is maximized up near 500 hPa in this case. Link to comment Share on other sites More sharing options...
IntenseBlizzard2014 Posted December 31, 2013 Share Posted December 31, 2013 what you are seeing is a 2-4" followed by a 6-8"....( 2 at 60hrs and 8 at 84hrs) Nice. Thanks. Link to comment Share on other sites More sharing options...
donsutherland1 Posted December 31, 2013 Share Posted December 31, 2013 From 0z through 12z, giving equal weight to all the GFS and ECMWF runs, qpf in NYC has averaged 0.45". Assuming snow ratios of 11:1 to 12.5:1, that would suggest a general 5"-6" snowfall across the NYC metro area. My thoughts are that a 3"-6"/4"-8"-type snowfall is probably the best bet at this time. There is still some uncertainty, but the model output has been moving toward convergence beginning at 12/31 0z. Although this isn't a KU snowstorm by any stretch, it's still a nice event if things play out as currently modeled. Link to comment Share on other sites More sharing options...
dabiggiu Posted December 31, 2013 Share Posted December 31, 2013 12z UKMET much wetter than GGEM at 72hr. Would love to compare the two at 66 if it was available since this would most likely be the height of the storm GGEM UKMET Link to comment Share on other sites More sharing options...
SACRUS Posted December 31, 2013 Share Posted December 31, 2013 12z UKMET much wetter than GGEM at 72hr. Would love to compare the two at 66 if it was available since this would most likely be the height of the storm GGEM UKMET The gfs, ecm and ukmet are similar in the progression and their qpf. GGEM continues to be very inconsistent. Link to comment Share on other sites More sharing options...
LVblizzard Posted December 31, 2013 Share Posted December 31, 2013 ^ The UKMET maps look much wetter because they show 12 hour precip rather than 2 hour precip. The UKMET is a better solution than the GGEM, but not as much as those maps appear to indicate at first glance. Link to comment Share on other sites More sharing options...
bluewave Posted December 31, 2013 Share Posted December 31, 2013 From 0z through 12z, giving equal weight to all the GFS and ECMWF runs, qpf in NYC has averaged 0.45". Assuming snow ratios of 11:1 to 12.5:1, that would suggest a general 5"-6" snowfall across the NYC metro area. My thoughts are that a 3"-6"/4"-8"-type snowfall is probably the best bet at this time. There is still some uncertainty, but the model output has been moving toward convergence beginning at 12/31 0z. Although this isn't a KU snowstorm by any stretch, it's still a nice event if things play out as currently modeled. Yeah, the highest totals will probably be in the areas where the coastal trough banding sets up early Friday. Link to comment Share on other sites More sharing options...
ag3 Posted December 31, 2013 Share Posted December 31, 2013 Summary of 12z Guidance NJ/NYC/LI (generally least to most SW to NE) NAM: 0.10 - 0.25 GFS: 0.25 - 0.50 GGEM: 0.05 - 0.20 ECM: 0.25 - 0.50 With that NE-NJ/NYC/LI : 3 - 6 CNJ: 2- 5 NYC is .40"-.50" on both the gfs and euro. LI is .40"-.60". Link to comment Share on other sites More sharing options...
dabiggiu Posted December 31, 2013 Share Posted December 31, 2013 ^ The UKMET maps look much wetter because they show 12 hour precip rather than 2 hour precip. The UKMET is a better solution than the GGEM, but not as much as those maps appear to indicate at first glance. Ahh good call.. Even looking at 6hr increments on the Canadian it's amazing how dry it is Link to comment Share on other sites More sharing options...
bluewave Posted December 31, 2013 Share Posted December 31, 2013 NYC is .40"-.50" on both the gfs and euro. LI is .40"-.60". It would be funny if Central New Jersey ends up with another surprise jackpot like the last two events. Link to comment Share on other sites More sharing options...
SACRUS Posted December 31, 2013 Share Posted December 31, 2013 NYC is .40"-.50" on both the gfs and euro. LI is .40"-.60". yes the range is from sw to ne nj-nyc/li thanks for the LI totals. Link to comment Share on other sites More sharing options...
ace0927 Posted December 31, 2013 Share Posted December 31, 2013 The NAM had really diffuse, light lift through most of the column and didn't make a great case for a demonstrative example, so I'm looking at the 12Z GFS for KEWR at 60 hours (7PM Thursday). plot1.png Here's your traditional Skew-T, with omega (upward vertical motion) plotted in the thin white line. On the temperature line, the dendritic snow growth region is highlighted in yellow (between -12C and -18C). You can see here there is lift occurring in many different temperature regions. The time series data is a bit easier to see this on: plot2.png This plot is kind of busy and hard to look at, but it shows temperature (gold lines), omega (red - UVV, blue - DVM), the dendritic snow growth region outlined in purple/yellow, and the shading shows the saturation with respect to ice. The vertical line is the 60 h forecast. You can once again see lift through a very broad layer of the atmosphere, including in the snow growth region (where supersaturation exists), but also above and below it. The maximal lift occurs after 00Z Friday and is maximized above the snow growth region. Here it is saturated and around -24C to -30C. The secondary maxima occurs in the -6C to -10C region. Forecasting snow ratios is tough and definitely not my forte, but based on these model runs at least I'd expect a wide range of crystal types given the depth of the (super)saturation and lift, the point being beautiful 20:1 ratios will likely not be the norm here, in accordance with the graph forky posted. Edited to add: As for the 700 hPa level being the source region, you can see here that the dendritic snow growth region actually descends from 600 hPa down to 800-900 hPa as the atmospheric profile becomes much colder with the storm's progression. The strongest lift is maximized up near 500 hPa in this case. WOW - thanks! A lot of info to take in. I am going to have to copy and paste this amd read a few hundred times in order to really understand it Link to comment Share on other sites More sharing options...
PB GFI Posted December 31, 2013 Share Posted December 31, 2013 It would be funny if Central New Jersey ends up with another surprise jackpot like the last two events. Link to comment Share on other sites More sharing options...
jm1220 Posted December 31, 2013 Share Posted December 31, 2013 I think we'll end up with a better surface low reflection near the coast if the 500mb trends continue to improve. I like the track of the vortmax underneath us and there are solid dynamics for a time. The progressiveness of the vorts though is what's making the models have fits and continuing inconsistency. The models seem to be getting there, let's hope 0z tonight brings a better result. Link to comment Share on other sites More sharing options...
poleshiftnow Posted December 31, 2013 Share Posted December 31, 2013 12Z JMA holds serve Link to comment Share on other sites More sharing options...
jm1220 Posted December 31, 2013 Share Posted December 31, 2013 WOW - thanks! I am going to have to copy and paste this amd read a few hundred times in order to really understand it 20-1 is very rare. I'd say if we're lucky we get 15-1. That would still be a 7-8" snowstorm if we get 0.50" liquid, which seems to be a good estimation for our area right now. 4-8" is probably the best call-Upton will likely hoist watches this afternoon. Link to comment Share on other sites More sharing options...
bluewave Posted December 31, 2013 Share Posted December 31, 2013 20-1 is very rare. I'd say if we're lucky we get 15-1. That would still be a 7-8" snowstorm if we get 0.50" liquid, which seems to be a good estimation for our area right now. 4-8" is probably the best call-Upton will likely hoist watches this afternoon. I think the last time we may have seen 20-1 may have been PD2 front end thump powderfest. Link to comment Share on other sites More sharing options...
LocoAko Posted December 31, 2013 Share Posted December 31, 2013 WOW - thanks! A lot of info to take in. I am going to have to copy and paste this amd read a few hundred times in order to really understand it No problem. Feel free to ask if anything doesn't make sense -- I'm not the clearest writer/explainer at times lol. Link to comment Share on other sites More sharing options...
riverrat Posted December 31, 2013 Share Posted December 31, 2013 i like the changes at H5 compared to 0z. another step in that direction and this will be bigger This. Link to comment Share on other sites More sharing options...
Stormlover74 Posted December 31, 2013 Share Posted December 31, 2013 I think the last time we may have seen 20-1 may have been PD2 front end thump powderfest. Jan 2004 clipper I believe was at least 20:1..something like 7" out of a 1/4" liquid Link to comment Share on other sites More sharing options...
forkyfork Posted December 31, 2013 Share Posted December 31, 2013 we had close to 20:1 ratios during the second half of the feb 2006 storm Link to comment Share on other sites More sharing options...
Monmouth_County_Jacpot Posted December 31, 2013 Share Posted December 31, 2013 Just curious is this system on land yet?? Link to comment Share on other sites More sharing options...
sferic Posted December 31, 2013 Share Posted December 31, 2013 jm1220 when do you see the first flakes flying in our neck of the woods and accumulating? So no sleet coming into Long Beach and then Lynbrook? Link to comment Share on other sites More sharing options...
FreeRain Posted December 31, 2013 Share Posted December 31, 2013 20-1 is very rare. I'd say if we're lucky we get 15-1. That would still be a 7-8" snowstorm if we get 0.50" liquid, which seems to be a good estimation for our area right now. 4-8" is probably the best call-Upton will likely hoist watches this afternoon. So then 15-1 would be the max? ...with the ratio average being lower? Say 10-1? Link to comment Share on other sites More sharing options...
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