A-L-E-X Posted March 30, 2011 Share Posted March 30, 2011 Some people have said you need -10 or -12C 850s...but if you have heavy enough precipitation or a strong enough low thats not the case...April 1982 the 850s were -5C or so as you can see here and it was snowing heavily during that time. http://www.meteo.psu...1982/us0406.php Wow, and that was an extremely cold storm! I bet the 850s were around that number for 4/96 and 4/03 also. Link to comment Share on other sites More sharing options...
nzucker Posted March 30, 2011 Share Posted March 30, 2011 Here's sref surface temps during height of storm. Weird that its so warm: freezing line almost in MAINE: It's a super low gradient, the 5C (40F) line is not near NYC either, so you have no idea if NYC is at 33-34 or 38-39. It also doesn't account for much topographical/orographic features which dictate there'd be colder areas under heavy banding in moderate elevation areas etc... Link to comment Share on other sites More sharing options...
Dsnowx53 Posted March 30, 2011 Share Posted March 30, 2011 ^ Since the mean is more east, there must be more misses/grazes with the storm itself than there were previously. Because of this, there are fewer members showing heavy precipitation and strong dynamical cooling--thus there are fewer colder members and more warm ones. Link to comment Share on other sites More sharing options...
A-L-E-X Posted March 30, 2011 Share Posted March 30, 2011 Here's sref surface temps during height of storm. Weird that its so warm: freezing line almost in MAINE: It's extremely unlikely that the surface 0 line would be in N NH and ME lol. Link to comment Share on other sites More sharing options...
ag3 Posted March 30, 2011 Share Posted March 30, 2011 NYC is still around 35 or so it appears, even on that map as, 5 degree celcius line is in South Jersey. Link to comment Share on other sites More sharing options...
A-L-E-X Posted March 30, 2011 Share Posted March 30, 2011 It's a super low gradient, the 5C (40F) line is not near NYC either, so you have no idea if NYC is at 33-34 or 38-39. It also doesn't account for much topographical/orographic features which dictate there'd be colder areas under heavy banding in moderate elevation areas etc... Yeah and Ive seen it snow quite heavily and accumulate rather well all the way up to 36 F Link to comment Share on other sites More sharing options...
Analog96 Posted March 30, 2011 Share Posted March 30, 2011 850s might be colder because of the east trend but the surface is warmer because the precip is not as heavy? BINGO! Link to comment Share on other sites More sharing options...
Analog96 Posted March 30, 2011 Share Posted March 30, 2011 Some people have said you need -10 or -12C 850s...but if you have heavy enough precipitation or a strong enough low thats not the case...April 1982 the 850s were -5C or so as you can see here and it was snowing heavily during that time. http://www.meteo.psu...1982/us0406.php And it just snowed last week with 850s of -2. Link to comment Share on other sites More sharing options...
nzucker Posted March 30, 2011 Share Posted March 30, 2011 Wow, and that was an extremely cold storm! I bet the 850s were around that number for 4/96 and 4/03 also. Storm was ridiculously cold in April 1982, -25C 850s over Upstate NY: 500: Link to comment Share on other sites More sharing options...
eduggs Posted March 30, 2011 Share Posted March 30, 2011 Even if it's 8"+ that "falls" I doubt that much would stick-- my upper end for the coast would be about half that amount. I would consider 2" anywhere along the coastal plain an impressive result. But speaking theoretically, the upper limit of potential is much higher. Wet aggregated snowflakes can accumulate very rapidly during intense snowfall. It only takes a few hours of 2-3" per hour rates to exceed 8" accumulation. Snow at these intensities will stick at temperatures above 40F. But melting and condensing do offset accumulating potential as the temperature rises above 34F or so. That's typically why elevation plays such a big role in accumulations. With a steep lapse rate, especially at night, and a period of heavy snow to dynamically cool surface temperatures to within a degree or two of freezing, snow will stick on everything and accumulate rapidly. Link to comment Share on other sites More sharing options...
Manny Posted March 30, 2011 Share Posted March 30, 2011 That's so weird---the surface is extremely warm, but not the 850s. All in all, seems at the height of the storm with the SREFS, that temps are still conducive for snow, especially at night. Link to comment Share on other sites More sharing options...
eduggs Posted March 30, 2011 Share Posted March 30, 2011 So you think 6" for NYC? That's actually higher than what I was thinking.... which was 4" I think T to 2" for NYC. I was just giving a hypothetical best case based on the Euro raw data. Link to comment Share on other sites More sharing options...
A-L-E-X Posted March 30, 2011 Share Posted March 30, 2011 I would consider 2" anywhere along the coastal plain an impressive result. But speaking theoretically, the upper limit of potential is much higher. Wet aggregated snowflakes can accumulate very rapidly during intense snowfall. It only takes a few hours of 2-3" per hour rates to exceed 8" accumulation. Snow at these intensities will stick at temperatures above 40F. But melting and condensing do offset accumulating potential as the temperature rises above 34F or so. That's typically why elevation plays such a big role in accumulations. With a steep lapse rate, especially at night, and a period of heavy snow to dynamically cool surface temperatures to within a degree or two of freezing, snow will stick on everything and accumulate rapidly. And with the well documented airport problems of measuring snowfall-- good luck getting them to measure it before half of it melts! As long as temps stay 33-34, I think we're ok.... April 1996 saw 13" of snow and whiteout conditions in the Hamptons on the night of April 9-10 with temps around 33-34. Link to comment Share on other sites More sharing options...
earthlight Posted March 30, 2011 Share Posted March 30, 2011 The surface really isn't that warm, the temperatures are probably in the mid 30s. Link to comment Share on other sites More sharing options...
ag3 Posted March 30, 2011 Share Posted March 30, 2011 That's so weird---the surface is extremely warm, but not the 850s. All in all, seems at the height of the storm with the SREFS, that temps are still conducive for snow, especially at night. Its not extremly warm. 40 degree line is south of Cape May, NJ. So NYC is probably about 34-36 degrees. Link to comment Share on other sites More sharing options...
A-L-E-X Posted March 30, 2011 Share Posted March 30, 2011 The surface really isn't that warm, the temperatures are probably in the mid 30s. This does sound like an April 96/97 scenario. Link to comment Share on other sites More sharing options...
eduggs Posted March 30, 2011 Share Posted March 30, 2011 ^ Since the mean is more east, there must be more misses/grazes with the storm itself than there were previously. Because of this, there are fewer members showing heavy precipitation and strong dynamical cooling--thus there are fewer colder members and more warm ones. I hate using the SREF mean as a discrete solution. It's unreliable at longer time frames because of the averaging of values and it is subject to misleading trends from run to run based on renegade and outlying individual member solutions. I find it more useful as an indicator of the range of possible solutions (i.e., the model spread). Link to comment Share on other sites More sharing options...
NEG NAO Posted March 30, 2011 Share Posted March 30, 2011 I would consider 2" anywhere along the coastal plain an impressive result. But speaking theoretically, the upper limit of potential is much higher. Wet aggregated snowflakes can accumulate very rapidly during intense snowfall. It only takes a few hours of 2-3" per hour rates to exceed 8" accumulation. Snow at these intensities will stick at temperatures above 40F. But melting and condensing do offset accumulating potential as the temperature rises above 34F or so. That's typically why elevation plays such a big role in accumulations. With a steep lapse rate, especially at night, and a period of heavy snow to dynamically cool surface temperatures to within a degree or two of freezing, snow will stick on everything and accumulate rapidly. April 2003 comes to mind of course 6 - 9 inches middle of the day even on the roads in central NJ temps low 30's - heavy snow....Also April 1996 - especially on the jersey shore at night heavy wet snow 6 - 8 inches - power outages trees down,,, Link to comment Share on other sites More sharing options...
earthlight Posted March 30, 2011 Share Posted March 30, 2011 I hate using the SREF mean as a discrete solution. It's unreliable at longer time frames because of the averaging of values and it is subject to misleading trends from run to run based on renegade and outlying individual member solutions. I find it more useful as an indicator of the range of possible solutions (i.e., the model spread). Excellent post. It's useful for trends also..this run ticked north and west of the last few. Link to comment Share on other sites More sharing options...
A-L-E-X Posted March 30, 2011 Share Posted March 30, 2011 April 2003 comes to mind of course 6 - 9 inches middle of the day even on the roads in central NJ temps low 30's - heavy snow.... Yeah, that was an awesome storm, even the south shore of LI got 7" of snow. Having an all daytime storm stick like that puts it right up there with the greats. Link to comment Share on other sites More sharing options...
NEG NAO Posted March 30, 2011 Share Posted March 30, 2011 Yeah, that was an awesome storm, even the south shore of LI got 7" of snow. Having an all daytime storm stick like that puts it right up there with the greats. what produced the accumulations was the intensity and huge flakes.............. Link to comment Share on other sites More sharing options...
A-L-E-X Posted March 30, 2011 Share Posted March 30, 2011 what produced the accumulations was the intensity and huge flakes.............. Yep, that was a very photogenic snowstorm-- I mean you could literally freeze frame every flake and see their dendrite structure even on wide zoom shots! Link to comment Share on other sites More sharing options...
eduggs Posted March 30, 2011 Share Posted March 30, 2011 I'd like to see more of a SLP response near the southeast coast by 36-42hrs on the NAM. The old SLP off the mid-atlantic coast cannot do the job. Link to comment Share on other sites More sharing options...
NEG NAO Posted March 30, 2011 Share Posted March 30, 2011 JB new update -is about to go way up with the accumulations and IMO really" sticking his neck out" on this one - we can all think of a way this could be mainly liquid in the metro or even a near miss.. http://www.weatherbell.com/jb/ Link to comment Share on other sites More sharing options...
A-L-E-X Posted March 30, 2011 Share Posted March 30, 2011 JB new update -is about to go way up with the accumulations and IMO really" sticking his neck out" on this one - we can all think of a way this could be mainly liquid in the metro or even a near miss.. http://www.weatherbell.com/jb/ lol he just loves to stick his neck out.... btw I just love his stellar graphics, which look like the digital version of Crayola crayons. Someone needs to teach JB how to color in between the lines Link to comment Share on other sites More sharing options...
CooL Posted March 30, 2011 Share Posted March 30, 2011 I definately see some improvements on the nam with the deeper trough, i dont think its there yet tho Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted March 30, 2011 Share Posted March 30, 2011 no comments on nam? thru 48hr trough a bit sharper then 12z and 18z, looking at 500mb. at 54hr looks a bit too late i think for cbb to really get going but SNE looks good. weird, because at 500mb it really pretty good but then i look at surface and its not as good. Link to comment Share on other sites More sharing options...
Manny Posted March 30, 2011 Share Posted March 30, 2011 Looks like the NAM gives people .1-.25" by Hour 48. Link to comment Share on other sites More sharing options...
earthlight Posted March 30, 2011 Share Posted March 30, 2011 It's definitely closer to the GFS solution at 6/12/18z...and the euro solution. it's inching in that direction Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted March 30, 2011 Share Posted March 30, 2011 Boston gets blasted.....wow! Link to comment Share on other sites More sharing options...
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