Ericjcrash Posted March 23, 2011 Share Posted March 23, 2011 There is no way Nassau will have an inch of snow by 15Z. Possible on grass, and grass counts. Link to comment Share on other sites More sharing options...
Rjay Posted March 23, 2011 Share Posted March 23, 2011 GFS has a pretty healthy dose of QPF.. 850 strattles NYC a good part of the time Freezing line well NW of the city tho http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/00/index_ten_l_loop.shtml Link to comment Share on other sites More sharing options...
Guest Pamela Posted March 23, 2011 Share Posted March 23, 2011 There is no way Nassau will have an inch of snow by 15Z. Couldn't agree more. The chance of an inch of snow actually accumulating in Nassau County during the month of March is on the same potential metaphysical plane as an ice storm in Hell.... has never happened, will never happen, can never happen... Link to comment Share on other sites More sharing options...
ORH_wxman Posted March 23, 2011 Share Posted March 23, 2011 Oh, thanks! I saw that 132dam was the first blue line and assumed it was the critical thickness. Good to know. Edit: And oh, I guess it would be hard to snow at 1320 dam too. Yeah the NCEP maps really puzzle me on those thicknesses....they do not list the critical thicknesses and I have no idea why. They go in 40m increments and skip over the critical values. The critical thickness for 850-700mb is 1540m and they list 1520 and 1560...leaving you guessing where the 1540m line is Link to comment Share on other sites More sharing options...
Isotherm Posted March 23, 2011 Share Posted March 23, 2011 We're saturated here at HPN up to like 600mb, so that's not a bad sounding, look at 24 on the 0z NAM. Temps are great, well below freezing at all levels. I mean, Tom, models aren't showing 1" of QPF for nothing: this storm is obviously going to have some decent bands. I mean look at what's going on out west, no lack of dynamics there with thundersnow, tornado warnings, blizzard conditions, etc. Also, I think that New Brunswick sounding might be snow, Jake. We had crazy heavy snow here Monday morning with one of the worst set-ups and warmest temp profiles I've seen. Surface was 39F with 850s of like -.2C and yet it stayed all snow when it increased in intensity. I think a small area of above freezing temperatures could be overcome by decent precipitation rates at the height of the storm. It'll certainly have some moderate bands, but the 1" QPF is mainly due to the long duration of the event, not the intensity of it. If temps were a couple degrees colder, that might cut it for NYC, but as it stands, I don't believe even moderate precip will be sufficient to accumulate more than 1" w/ sfc temp of around 34F. You'll do better up your way, probably 3 or 4 inches. Going to be a sharp drop-off NW to SE with totals. Link to comment Share on other sites More sharing options...
ORH_wxman Posted March 23, 2011 Share Posted March 23, 2011 We're saturated here at HPN up to like 600mb, so that's not a bad sounding, look at 24 on the 0z NAM. Temps are great, well below freezing at all levels. I mean, Tom, models aren't showing 1" of QPF for nothing: this storm is obviously going to have some decent bands. I mean look at what's going on out west, no lack of dynamics there with thundersnow, tornado warnings, blizzard conditions, etc. Also, I think that New Brunswick sounding might be snow, Jake. We had crazy heavy snow here Monday morning with one of the worst set-ups and warmest temp profiles I've seen. Surface was 39F with 850s of like -.2C and yet it stayed all snow when it increased in intensity. I think a small area of above freezing temperatures could be overcome by decent precipitation rates at the height of the storm. Your 850 temps were much much colder than -0.2C while you snowed and there very strong vertical velocities in the Mar 21 system. Both factors may be in question for this one. On Mar 21, the main question was boundary layer which the models predicted a tad too warm as dynamical cooling managed to lower the freezing level enough to give some snow during that heavy precip. Link to comment Share on other sites More sharing options...
Isotherm Posted March 23, 2011 Share Posted March 23, 2011 It'll certainly have some moderate bands, but the 1" QPF is mainly due to the long duration of the event, not the intensity of it. If temps were a couple degrees colder, that might cut it for NYC, but as it stands, I don't believe even moderate precip will be sufficient to accumulate more than 1" w/ sfc temp of around 34F. You'll do better up your way, probably 3 or 4 inches. Going to be a sharp drop-off NW to SE with totals. Also, the dynamics are lessening / storm is weakening on its way SE (similar to the overrunning event of late feb actually). Link to comment Share on other sites More sharing options...
nzucker Posted March 23, 2011 Share Posted March 23, 2011 Your 850 temps were much much colder than -0.2C while you snowed and there very strong vertical velocities in the Mar 21 system. Both factors may be in question for this one. On Mar 21, the main question was boundary layer which the models predicted a tad too warm as dynamical cooling managed to lower the freezing level enough to give some snow during that heavy precip. Really? I thought the GFS the night of the event showed the 0C 850s passing NYC quickly and leaving mostly rain. The boundary layer was definitely worse than now though too, I was at like 39/30 when the event started while tonight dewpoints are running well into the mid 20s. Link to comment Share on other sites More sharing options...
ORH_wxman Posted March 23, 2011 Share Posted March 23, 2011 Really? I thought the GFS the night of the event showed the 0C 850s passing NYC quickly and leaving mostly rain. The boundary layer was definitely worse than now though too, I was at like 39/30 when the event started while tonight dewpoints are running well into the mid 20s. The 850 0C line didn't pass through until later during the afternoon...when you snowed in the morning, 850s were still in the -3C range. The key though was the very intense dynamics, something this system just seems to be lacking right now...perhaps that will change, but right now, the UVVs do not look very impressive unlike the Mar 21 system which had very intense UVVs. Doesn't mean there won't be accumulating snow...esp where you are...but it makes it more difficult and might take longer. Link to comment Share on other sites More sharing options...
nzucker Posted March 23, 2011 Share Posted March 23, 2011 The 850 0C line didn't pass through until later during the afternoon...when you snowed in the morning, 850s were still in the -3C range. The key though was the very intense dynamics, something this system just seems to be lacking right now...perhaps that will change, but right now, the UVVs do not look very impressive unlike the Mar 21 system which had very intense UVVs. Doesn't mean there won't be accumulating snow...esp where you are...but it makes it more difficult and might take longer. Wow I didn't think 850s remained that cold through like 14z...I do know some of the QPF was supposed to be rain and it basically shut down once the snow ended. Sitting at 40/29 right now, we'll see, I do like how the GFS is generating strong lift from N PA to NYC metro where that gradient is with the Canadian high, we get like 24 hours worth of WAA precip with a 1032mb high over SE Canada and 850s well below 0C. Link to comment Share on other sites More sharing options...
rgwp96 Posted March 23, 2011 Share Posted March 23, 2011 just started to snow here, temp at 38.6 when the snow started Link to comment Share on other sites More sharing options...
eduggs Posted March 23, 2011 Share Posted March 23, 2011 The 850 0C line didn't pass through until later during the afternoon...when you snowed in the morning, 850s were still in the -3C range. The key though was the very intense dynamics, something this system just seems to be lacking right now...perhaps that will change, but right now, the UVVs do not look very impressive unlike the Mar 21 system which had very intense UVVs. Doesn't mean there won't be accumulating snow...esp where you are...but it makes it more difficult and might take longer. From what I remember, the 0 degree isotherm passed NE of the area just before noon and dropped from roughly -2 to -1C during the snowfall. Antecedent wet bulb temps were similar to what they are tonight. I agree that precip intensity was the critical factor and will likely determine snow vs. slush vs. rain this go around as well. The lower hudson valley should be right on the edge of nuisance vs. plowable snow. Right now I think plowable stays confined to areas above 500ft or so. One positive compared to the Mon, 21st snow is that the window is much larger this time. Much of this region stays near or just north of the 0 degree isotherms with precip lasting through Thurs morning so there could be multiple opportunities for a burst of accumulating snow. Link to comment Share on other sites More sharing options...
nzucker Posted March 23, 2011 Share Posted March 23, 2011 Radar is starting to light up for the NYC metro, and looking good. As is often the case with WAA precip, it should arrive ahead of schedule. Link to comment Share on other sites More sharing options...
Isotherm Posted March 23, 2011 Share Posted March 23, 2011 Here's my idea regarding snowfall totals in map form, not the prettiest but it gets the job done. Link to comment Share on other sites More sharing options...
NorthShoreWx Posted March 23, 2011 Share Posted March 23, 2011 That event much like 3/14/99 there was a glaring QPF gradient between NYC and Nassau county, the heavier echoes in both never really made it much west of Queens and that more than anything caused the big difference in amounts from west to east. QPF at Cental Park was almost identical to ISP on 4/9-10/1996, at least thats whats in the record: http://www.northshor...10Snowstorm.gif Link to comment Share on other sites More sharing options...
nzucker Posted March 23, 2011 Share Posted March 23, 2011 Six pack on 3.5", Tom? Link to comment Share on other sites More sharing options...
CoastalWx Posted March 23, 2011 Share Posted March 23, 2011 Radar is starting to light up for the NYC metro, and looking good. As is often the case with WAA precip, it should arrive ahead of schedule. You'll have to watch the radar over NW NJ. They might have a nice surprise by morning. That area through he Catskills looks nice. Link to comment Share on other sites More sharing options...
Isotherm Posted March 23, 2011 Share Posted March 23, 2011 Six pack on 3.5", Tom? , for your backyard I'm assuming? Or NYC? Link to comment Share on other sites More sharing options...
earthlight Posted March 23, 2011 Share Posted March 23, 2011 Much of the analysis of the NAM being very similar or just as good as it's 12z and 18z runs was really awful...and wrong. The NAM is at least 50 miles further north with the H85 0c line and the thermal profiles have warmed a good bit. I included the 00z and 18z runs below for a comparison. http://www.meteo.psu.edu/~gadomski/ETAPA_0z/f27.gif http://www.meteo.psu.edu/~gadomski/ETAPA_18z/f33.gif Link to comment Share on other sites More sharing options...
Manny Posted March 23, 2011 Share Posted March 23, 2011 I don't know how NYC sees 1" out of .7-1" of QPF. Yes, temps will be marginal, but once the coastal cranks, temps at night will follow suit, and the city should squeeze out 2-4" or even 3-5" whether or not its on the grass. Link to comment Share on other sites More sharing options...
rgwp96 Posted March 23, 2011 Share Posted March 23, 2011 You'll have to watch the radar over NW NJ. They might have a nice surprise by morning. That area through he Catskills looks nice. didnt take long for the snow to start here in nw jersey. temp still warm at 37. high point already at 32 Link to comment Share on other sites More sharing options...
nzucker Posted March 23, 2011 Share Posted March 23, 2011 You'll have to watch the radar over NW NJ. They might have a nice surprise by morning. That area through he Catskills looks nice. Yeah there's a lot of 30+dbz flashing to my NW. Definitely getting more optimistic now with temps down in the 30s (but oh how barely at 39.9/30). Will have to be watched. Link to comment Share on other sites More sharing options...
Isotherm Posted March 23, 2011 Share Posted March 23, 2011 Much of the analysis of the NAM being very similar or just as good as it's 12z and 18z runs was really awful...and wrong. The NAM is at least 50 miles further north with the H85 0c line and the thermal profiles have warmed a good bit. I included the 00z and 18z runs below for a comparison. http://www.meteo.psu...TAPA_0z/f27.gif http://www.meteo.psu...APA_18z/f33.gif Strongly agree, the GFS has been much more consistent with this storm, and I also thought the 00z NAM was worse than prior runs. Link to comment Share on other sites More sharing options...
earthlight Posted March 23, 2011 Share Posted March 23, 2011 Strongly agree, the GFS has been much more consistent with this storm, and I also thought the 00z NAM was worse than prior runs. Boundary layer winds are also veering to the east on most models now during the best isentropic lifting which could be an absolute atrocious development along the shore. That's a good way to waste 0.75" of QPF in late march---marginal thermal profiles at 700-850 mb, poor moisture in the snow growth region, and a warm boundary layer and poor wind direction. Link to comment Share on other sites More sharing options...
pazzo83 Posted March 23, 2011 Share Posted March 23, 2011 Still in the mid 40s in the city. Link to comment Share on other sites More sharing options...
ORH_wxman Posted March 23, 2011 Share Posted March 23, 2011 I don't know how NYC sees 1" out of .7-1" of QPF. Yes, temps will be marginal, but once the coastal cranks, temps at night will follow suit, and the city should squeeze out 2-4" or even 3-5" whether or not its on the grass. The ML temps are question too and a potential fly in the ointment. GFS flips NYC to rain for a chunk of the qpf and even the NAM flips them for a period now. Link to comment Share on other sites More sharing options...
nzucker Posted March 23, 2011 Share Posted March 23, 2011 , for your backyard I'm assuming? Or NYC? Well I was thinking of me since the 3" line basically bisects my house on your drawing...I'm just north of the NJ/NY border looking across the Hudson. I'd be a little more hesitant to bet on Central Park though I think they will get it. Agree, John, that the NAM obviously trended warmer as opposed to its earlier runs, but we all knew those were BS anyway. It's basically come into a nice consensus with the ECM/SREF etc...What I still don't understand is how the GFS can be so much warmer with the track so similar. Link to comment Share on other sites More sharing options...
Isotherm Posted March 23, 2011 Share Posted March 23, 2011 Yeah there's a lot of 30+dbz flashing to my NW. Definitely getting more optimistic now with temps down in the 30s (but oh how barely at 39.9/30). Will have to be watched. That dew point is fairly high, and your wetbulb is around 35-36 right now, Need those numbers to drop at least a couple degrees to support accumulating snow. Link to comment Share on other sites More sharing options...
stockmanjr Posted March 23, 2011 Share Posted March 23, 2011 If you remember, the plate umpire Derryl Cousins was wearing his red short sleeve shirt that game. Yep we knew when we saw that the game was going to be played to it's completion! It was also passover and while we don't keep kosher we avoid bread and that made things even tricker.. Link to comment Share on other sites More sharing options...
Manny Posted March 23, 2011 Share Posted March 23, 2011 The ML temps are question too and a potential fly in the ointment. GFS flips NYC to rain for a chunk of the qpf and even the NAM flips them for a period now. I know QPF will be wasted, but snow is snow, and it'll be great to see snow still flying in the air for a good period of time. Link to comment Share on other sites More sharing options...
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