IsentropicLift Posted December 12, 2013 Author Share Posted December 12, 2013 Hour 63 heavy snow for everyone from KSWF south. Edit, surface freezing line hanging near the city, 850's well south. Link to comment Share on other sites More sharing options...
earthlight Posted December 12, 2013 Share Posted December 12, 2013 That 850 low in the midwest still concerns me: More important to note the trend over the past several runs, steadier and farther south. This is important as the primary not driving so far northwest will help interior areas with the warm tongue between 800-900 or so mb. Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted December 12, 2013 Share Posted December 12, 2013 That 850 low in the midwest still concerns me: Without that low we have no WAA snow. I know but we should be pulling for the coastal ala gfs no? Link to comment Share on other sites More sharing options...
Storm At Sea Posted December 12, 2013 Share Posted December 12, 2013 Good rule of thumb...half the WAA snow QPF, double CAA snow QPF. FWIW...indices are fluid. Folks are too concrete. The best way to view indices are as shifting mechanisms. Just like 2+2 is not the only way to get 4, -NAO + +PNA is not the only way to East Coast snow. I think if the initial WAA snows affect us, we could see the high end of that, maybe 4-6". If the initial overrunning overshoots us and goes mostly through SNE, we will likely have only 2-3". But I'm liking the colder model trends, maybe we can salvage this with very little plain rain. Link to comment Share on other sites More sharing options...
earthlight Posted December 12, 2013 Share Posted December 12, 2013 850mb 0c is near Philly with heavy precipitation at 63 hours... but need to see soundings. There could be a warm layer sneaking in there. 540 thickness sitting over NYC. Link to comment Share on other sites More sharing options...
IsentropicLift Posted December 12, 2013 Author Share Posted December 12, 2013 Hour 66, city and LI flip to plain rain. Ugly ice storm NW of I-95. Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted December 12, 2013 Share Posted December 12, 2013 850mb 0c is near Philly with heavy precipitation at 63 hours... but need to see soundings. There could be a warm layer sneaking in there. 540 thickness sitting over NYC. I95 is usually our r/s line down this way....I see it no different this time. Link to comment Share on other sites More sharing options...
earthlight Posted December 12, 2013 Share Posted December 12, 2013 Not hard to see the changes when compared to the 00 and 06z runs. Stronger and faster to transfer to the secondary coastal low. This run has got to be a ton of ZR in the suburbs. Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted December 12, 2013 Share Posted December 12, 2013 Nam Is still tucking the secondary in tight to the coast. Could be its bias in play here but certainly looks colder for most this run. Link to comment Share on other sites More sharing options...
IsentropicLift Posted December 12, 2013 Author Share Posted December 12, 2013 I-287 looks to be the cut off between just some glazing and significant icing this run. Link to comment Share on other sites More sharing options...
IsentropicLift Posted December 12, 2013 Author Share Posted December 12, 2013 I wonder if having a solid few inches of snow is going to make any icing worse? You would think any snow on power line or branches would be encased in ice and become heavy but I really don't know. Link to comment Share on other sites More sharing options...
allgame830 Posted December 12, 2013 Share Posted December 12, 2013 if the NAM verifies correct then we really need to hope for it being to warm because that is some serious icing about 30 N and NW of NYC... Link to comment Share on other sites More sharing options...
jm1220 Posted December 12, 2013 Share Posted December 12, 2013 Nam Is still tucking the secondary in tight to the coast. Could be its bias in play here but certainly looks colder for most this run. It will probably be flatter the way the GFS shows, but it's good to finally see it coming back to reality with cold air hanging tough just inland. A weak system like this won't drive warm air all the way inland. It might even be possible for coastal areas to stay below freezing if winds don't veer to the east or ESE. I don't see it warming up much if winds have a northerly component. Link to comment Share on other sites More sharing options...
IsentropicLift Posted December 12, 2013 Author Share Posted December 12, 2013 NAM snow maps showing 12-18" for Sullivan County 6-12" for Orange County on a NW to SE gradient A coating to 2" for the city and immediate burbs, less for LI A general 3-6"+ for almost all of northern NJ from I-78 north. Link to comment Share on other sites More sharing options...
bluewave Posted December 12, 2013 Share Posted December 12, 2013 Good rule of thumb...half the WAA snow QPF, double CAA snow QPF. FWIW...indices are fluid. Folks are too concrete. The best way to view indices are as shifting mechanisms. Just like 2+2 is not the only way to get 4, -NAO + +PNA is not the only way to East Coast snow. It comes down to the -EPO providing the low level cold and the +AO allowing the primary to cut to the Lakes with WAA just above the shallow surface cold layer. Link to comment Share on other sites More sharing options...
IsentropicLift Posted December 12, 2013 Author Share Posted December 12, 2013 If the 4k NAM is correct, all of the precip up to hour 60 is very scattered and broken up in nature. Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted December 12, 2013 Share Posted December 12, 2013 Nam still the warmest model but did get colder especially in terms of surface temps even down this way. Link to comment Share on other sites More sharing options...
PB GFI Posted December 12, 2013 Share Posted December 12, 2013 Careful , the NAM has had issues in the past warming the surface too quickly , at hour 66 its 5 degrees warmwer at the surface right around the city then the better Global Models at this range are . Its one of the Colder NAM runs , still warmer than the GFS and the Euro , Link to comment Share on other sites More sharing options...
earthlight Posted December 12, 2013 Share Posted December 12, 2013 There's definitely a warm layer in around 925mb..you can see the 925mb low transferring to the coast. But the NAM still seems to be adjusting towards the colder solutions. Link to comment Share on other sites More sharing options...
supermeh Posted December 12, 2013 Share Posted December 12, 2013 Remember the NAM is usually NW of guidance at this point in time compared to the globals. You really shouldn't be looking at specifics from it for another day or so. Just look for trends. Link to comment Share on other sites More sharing options...
NEG NAO Posted December 12, 2013 Share Posted December 12, 2013 Nam still the warmest model but did get colder especially in terms of surface temps even down this way. NAM IS TOO WARM IN THE BOUNDARY LAYER...ESPECIALLY INLAND WHERE COLD AIR DAMMING SHOULD HANG IN LONGER THAN MODEL FCST...AND EVEN AT THE COAST WHERE SNOWFALL SHOULD COUNTERACT WARMING ON EASTERLY FLOW. Link to comment Share on other sites More sharing options...
IsentropicLift Posted December 12, 2013 Author Share Posted December 12, 2013 NAM IS TOO WARM IN THE BOUNDARY LAYER...ESPECIALLY INLAND WHERE COLD AIR DAMMING SHOULD HANG IN LONGER THAN MODEL FCST...AND EVEN AT THE COAST WHERE SNOWFALL SHOULD COUNTERACT WARMING ON EASTERLY FLOW. Those by the coast better hope so because the 12z NAM is like a coating to heavy rain for coastal sections. Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted December 12, 2013 Share Posted December 12, 2013 NAM IS TOO WARM IN THE BOUNDARY LAYER...ESPECIALLY INLAND WHERE COLD AIR DAMMING SHOULD HANG IN LONGER THAN MODEL FCST...AND EVEN AT THE COAST WHERE SNOWFALL SHOULD COUNTERACT WARMING ON EASTERLY FLOW. Source? Link to comment Share on other sites More sharing options...
jm1220 Posted December 12, 2013 Share Posted December 12, 2013 Those by the coast better hope so because the 12z NAM is like a coating to heavy rain for coastal sections. That's not true. No one near the coast changes over to rain until maybe 10-11pm. Coastal NJ appears to be a different story with temps making it into the 40s before then. At 10pm the city is still below freezing. If the coastal redevelopment is further east, as all other models show, the cold air will be even more stout at the coast because winds will be more northerly. Link to comment Share on other sites More sharing options...
REDMK6GLI Posted December 12, 2013 Share Posted December 12, 2013 Unless the globals show that then I'm not buying it, the Nam is still out of its range and has a warm bias. Very true NAM is always too warm and even in the 48-60 hr range it can still be quite inaccurate. The 12z GFS run coming soon should be more "reasonable" if you will. Still early december lets all keep this in mind as well Link to comment Share on other sites More sharing options...
IsentropicLift Posted December 12, 2013 Author Share Posted December 12, 2013 That's not true. No one near the coast changes over to rain until maybe 10-11pm. Coastal NJ appears to be a different story with temps making it into the 40s before then. At 10pm the city is still below freezing. If the coastal redevelopment is further east, as all other models show, the cold air will be even more stout at the coast because winds will be more northerly. Excuse me? At 06z The 850mb freezing line is north of I-287 in NY and the surface freezing line is almost inland to KMMU, and that's when the heaviest precip falls associated with the coastal. The snow maps show less than an inch for the city and immediate burbs, and nothing for LI. Link to comment Share on other sites More sharing options...
PB GFI Posted December 12, 2013 Share Posted December 12, 2013 I will stay with the Euro , Not because I like the solution , but because the trend by EVERY model has been to the colder solutuion over the past 3 days the NAM has been a day behind for 2 days now but has stepped colder and will be inside its best range 48 and in .For me LOW level cold air and the CAD signal on every model is very hard to scour with an ejecting low ESE headin to the BM . The trend of the this system is colder and wetter , when I see that trend stop , i will buy the NAM Link to comment Share on other sites More sharing options...
IsentropicLift Posted December 12, 2013 Author Share Posted December 12, 2013 The 4k 12z NAM is a bit more generous with snowfall totals showing 1-3" for the city and LI by hour 60 and much more than that inland. Link to comment Share on other sites More sharing options...
jm1220 Posted December 12, 2013 Share Posted December 12, 2013 Excuse me? At 06z The 850mb freezing line is north of I-287 in NY and the surface freezing line is almost inland to KMMU, and that's when the heaviest precip falls associated with the coastal. The snow maps show less than an inch for the city and immediate burbs, and nothing for LI. What's with the reliance on snow maps here, which 90% of the time are wrong? I could care less about a snow map, use soundings instead. And those at least favor frozen for the vast majority of the area until 10pm, even on this run which is still likely too tucked into the coast with the redevelopment. Link to comment Share on other sites More sharing options...
allgame830 Posted December 12, 2013 Share Posted December 12, 2013 where do you find the snow maps for the models? is that on a paid site? Link to comment Share on other sites More sharing options...
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