DTWXRISK Posted January 20, 2016 Share Posted January 20, 2016 The 12z op ECMWF is an outlier neither the 0z euro ensemble mean ...the high res GEFS ensemnle mean ...or the cmc ensemble mean have nearly the same as the 12z op ECMWF for snow in north NJ NYC LI or CT Link to comment Share on other sites More sharing options...
Drz1111 Posted January 20, 2016 Share Posted January 20, 2016 The 12z op ECMWF is an outlier neither the 0z euro ensemble mean ...the high res GEFS ensemnle mean ...or the cmc ensemble mean have nearly the same as the 12z op ECMWF for snow in north NJ NYC LI or CT I've never heard of arguing that an operation run is an outlier compared to its ensembles . . . from 12 hours prior. But Tolleris never fails to surprise. Link to comment Share on other sites More sharing options...
RU848789 Posted January 20, 2016 Share Posted January 20, 2016 QPF is quantitative precipitation forecast. With global models (gfs/cmc/euro to a lesser extent), the QPF naps are notoriously bad. If you look at h5/h7 on the gfs, it's 12-24". Sent from my SAMSUNG-SM-N910A using Tapatalk I know what QPF is - bad attempt at humor. I always assumed people were using the precipitation maps to forecast precipitation amounts - if not, why have the QPF maps for the surface if there is some algorithm that converts some variable (pressure/height, I presume) at mid/upper levels of the atmosphere (700/500 mbar) into surface precip amounts more accurately? I'm not a forecaster, so am interested to understand this... Also, I'm pretty sure sacrus, zelocita, donsutherland, et al, have been posting guesstimated snowfall amounts based on those QPF maps, but I could be wrong. At the very least, listing them out like that is an apples to apples comparison of QPF maps. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted January 20, 2016 Share Posted January 20, 2016 The 12z op ECMWF is an outlier neither the 0z euro ensemble mean ...the high res GEFS ensemnle mean ...or the cmc ensemble mean have nearly the same as the 12z op ECMWF for snow in north NJ NYC LI or CT It's more or less model noise though, the variance is an issue of 40-60 mile differences between the various guidance. Right now I think anything from 8 to 20 inches in NYC is possible with anything over that being extremely unlikely and anything under that being relatively unlikely Link to comment Share on other sites More sharing options...
Drz1111 Posted January 20, 2016 Share Posted January 20, 2016 He is also comparing it to the ensembles of a previous run... DT just likes to come on our subforum and stir the pot and leave. It's total bull****. It goes into the weighted blend like all the other runs. If it is a true outlier, it won't influence the forecast that much because that blend will also have the GFS, Canadian, UKMET, GFS and ECWMF ensembles, etc. You don't just get to throw away a model because you don't like its output without reasoning why it should be discarded. Link to comment Share on other sites More sharing options...
forkyfork Posted January 20, 2016 Share Posted January 20, 2016 The 12z op ECMWF is an outlier neither the 0z euro ensemble mean ...the high res GEFS ensemnle mean ...or the cmc ensemble mean have nearly the same as the 12z op ECMWF for snow in north NJ NYC LI or CT to be fair the total precip might not be as much as the op run but the ens mean has a further north edge than the op Link to comment Share on other sites More sharing options...
DTWXRISK Posted January 20, 2016 Share Posted January 20, 2016 um HOW is the 12z CMC ENSEMBLE snow projection 10-18"? this map does not show that at all an 20 12z Summary NYC: Snowfall projections NAM: great thru 84 - extrapolated looks 12-20 GFS: 7 - 11 GEFS GGEM: 15 - 22 GGEM ENS: 10 - 18 UKMET: ECM: 10 - 18 Link to comment Share on other sites More sharing options...
danstorm Posted January 20, 2016 Share Posted January 20, 2016 More and more, I see snowfall distribution being similar to 12/09/09 ... probably without the crazy death band over LI/SE Ct (thought that was a total surprise, too). Link to comment Share on other sites More sharing options...
DTWXRISK Posted January 20, 2016 Share Posted January 20, 2016 HPC does this all the time they will reject the recent op run of a model when they compare e top the 0z ens mean It's total bull****. It goes into the weighted blend like all the other runs. If it is a true outlier, it won't influence the forecast that much because that blend will also have the GFS, Canadian, UKMET, GFS and ECWMF ensembles, etc. You don't just get to throw away a model because you don't like its output without reasoning why it should be discarded. Link to comment Share on other sites More sharing options...
friedmators Posted January 20, 2016 Share Posted January 20, 2016 toasty off the SE coast Link to comment Share on other sites More sharing options...
danstorm Posted January 20, 2016 Share Posted January 20, 2016 um HOW is the 12z CMC ENSEMBLE snow projection 10-18"? this map does not show that at all Heard you twice the first time, Dave-O Link to comment Share on other sites More sharing options...
nyblizz44 Posted January 20, 2016 Share Posted January 20, 2016 It's more or less model noise though, the variance is an issue of 40-60 mile differences between the various guidance. Right now I think anything from 8 to 20 inches in NYC is possible with anything over that being extremely unlikely and anything under that being relatively unlikely Perfect example of how language, when used precisely, helps to clarify the picture. Understand that spread and the % involved. Other than confluence reduction , a possible 2nd low and excessive wind what can hold back NYC from the 15-20 range? Link to comment Share on other sites More sharing options...
DTWXRISK Posted January 20, 2016 Share Posted January 20, 2016 good post but the ggem does not really show 10-18" for NYC CT LI It's more or less model noise though, the variance is an issue of 40-60 mile differences between the various guidance. Right now I think anything from 8 to 20 inches in NYC is possible with anything over that being extremely unlikely and anything under that being relatively unlikely Link to comment Share on other sites More sharing options...
Drz1111 Posted January 20, 2016 Share Posted January 20, 2016 HPC does this all the time they will reject the recent op run of a model when they compare e top the 0z ens mean Not without additional reasoning for the rejection. It's a way to support rejection for a real reason, not a "doesn't agree with my preferred forecast reason'. I.e., if you suspected some error in the data that was input, and then you got a result that was vastly different from the last run's ensemble, then you might reject. What you're doing is cherry-picking based on gut. That's not rigorous forecasting. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted January 20, 2016 Share Posted January 20, 2016 good post but the ggem does not really show 10-18" for NYC CT LI I'm terrified to trust that damn model though although I did post earlier it seems to do well in situations where there is confluence to the north that negates it's bias of trying to bomb and bring everything northwest Link to comment Share on other sites More sharing options...
Brian5671 Posted January 20, 2016 Share Posted January 20, 2016 good post but the ggem does not really show 10-18" for NYC CT LI it shows 8-12 give or take-doesnt really matter at this juncture. Link to comment Share on other sites More sharing options...
WeatherFeen2000 Posted January 20, 2016 Share Posted January 20, 2016 The 12z op ECMWF is an outlier neither the 0z euro ensemble mean ...the high res GEFS ensemnle mean ...or the cmc ensemble mean have nearly the same as the 12z op ECMWF for snow in north NJ NYC LI or CT do you think the small snowstorm that's about to cross the mid Atlantic has anything to do how the next storm that's supposed to hit this weekend ?will it influence the big storm once the small one crosses into the ocean? You think he models will catch any changes after it rolls through Link to comment Share on other sites More sharing options...
donsutherland1 Posted January 20, 2016 Share Posted January 20, 2016 WOW... according to the GFS... HPN is not that far off from the NYC airport outputs... thought they were further apart. Either could translate to 8-12 inches. thanks for the post DON! It will be interesting to see if the higher-resolution ECMWF or the GFS have a better idea on the northern extent of the accumulations. It's gone both ways in past storms, so the higher amounts shown on the GFS can't necessarily be thrown out. Moreover, for all intents and purposes, the ECMWF is in the same ballpark so to speak. Link to comment Share on other sites More sharing options...
wthrmn654 Posted January 20, 2016 Share Posted January 20, 2016 Looking at this map,one can easily see a call if 10-18 FOR NYC ONLY makes sense.. his snow totals are for NYC only not long island etc. It says so in his post. Link to comment Share on other sites More sharing options...
PB GFI Posted January 20, 2016 Share Posted January 20, 2016 good post but the ggem does not really show 10-18" for NYC CT LI He sees 1.25 +shaded through KNYC That supports 12 plus 1.5 cuts into the tip of Staten Island. 1.75 cutting through Monmouth County . It is 30 miles S of KNYC S of the tip on KNYC Link to comment Share on other sites More sharing options...
UlsterCountySnowZ Posted January 20, 2016 Share Posted January 20, 2016 Albany NWS seems to think there's gonna be decent wiggle room on that northern Precip shield.. Stating that anyone south of I-90 is at greatest chance for accumulating snows... Link to comment Share on other sites More sharing options...
snowman19 Posted January 20, 2016 Share Posted January 20, 2016 Albany NWS seems to think there's gonna be decent wiggle room on that northern Precip shield.. Stating that anyone south of I-90 is at greatest chance for accumulating snows...NYC looks like 6+ minimum. With how this year has gone so far, take it and run. North and west of NYC is the big question mark Link to comment Share on other sites More sharing options...
acvyse Posted January 20, 2016 Share Posted January 20, 2016 I don't think anyone should be calling accumulations until tomorrow. Link to comment Share on other sites More sharing options...
UlsterCountySnowZ Posted January 20, 2016 Share Posted January 20, 2016 NYC looks like 6+ minimum. With how this year has gone so far, take it and run. North and west of NYC is the big question mark Just posted this in the NW thread and is obviously as good as garbage but I'm really desperate here.. Lol... The SREFS are surprisingly wet.... But then again..... When aren't they? Link to comment Share on other sites More sharing options...
IsentropicLift Posted January 20, 2016 Share Posted January 20, 2016 15Z SREF is better than 09z Link to comment Share on other sites More sharing options...
psuhoffman Posted January 20, 2016 Share Posted January 20, 2016 This could be a "revenge Juno" where Boston gets shafted and NYC gets a nice event. The models shifting to a sharp north cutoff isn't an accident. But 2/6/10 just 50 miles further north would have included millions more people in over 12" of snow. The confluence this time looks weaker than that time. One of these looks slightly more suppressive then the other... Link to comment Share on other sites More sharing options...
SACRUS Posted January 20, 2016 Share Posted January 20, 2016 Looking at this map,one can easily see a call if 10-18 FOR NYC ONLY makes sense.. his snow totals are for NYC only not long island etc. It says so in his post. 8-14 more like it. At the time i had based the tally on the 6 hour frames and summed them up. Anyway, I usually prefer to just list QPF and let others decide on snow totals. Link to comment Share on other sites More sharing options...
UlsterCountySnowZ Posted January 20, 2016 Share Posted January 20, 2016 SREFS drop a mean of .54 LE by HR 84... With the a max possibility of 1.8"!!! Lol the storms not even hitting hard up here at 84 lol, the city would be buried if that verified Link to comment Share on other sites More sharing options...
Drz1111 Posted January 20, 2016 Share Posted January 20, 2016 NYC looks like 6+ minimum. With how this year has gone so far, take it and run. North and west of NYC is the big question mark Really? 75 mile shift means NYC gets nothing. "Minimum" for NYC is 0.0. Link to comment Share on other sites More sharing options...
hudsonvalley21 Posted January 20, 2016 Share Posted January 20, 2016 SREFS drop a mean of .54 LE by HR 84... With the a max possibility of 1.8"!!! Lol the storms not even hitting hard up here at 84 lol, the city would be buried if that verified A 50 mile shift either way could make a big difference. We might not know until the 00z runs Friday. Link to comment Share on other sites More sharing options...
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