weatherMA Posted December 31, 2013 Share Posted December 31, 2013 It's just statistically produced from what the model has for hard numbers for specific variables at different levels. 8+ at ORH isn't that extreme for 0.75" QPF. No, not at all, but seems a little extreme for 14-16+, no? 1 means 1-2" of snow in that 6 hour period 2 means 2-4" 4 means 4-6" 6 means 6-8" 8 means 8"+ so a 6 and an 8 in back to back 6 hour periods would theoretically mean 6-8" followed by 8"+....obviously a big snow total. I don't thjink I'd bite on that type of total at this point though. Link to comment Share on other sites More sharing options...
dtk Posted December 31, 2013 Share Posted December 31, 2013 Don't quote me, but GFS is 27km and EC 15km? Without risking looking like a fool, DTK is best for these questions. -ish. That's close enough for the sake of argument. To clarify earlier discussion, the lower boundary condition I was quoted on earlier is only relevant to the GFS. The NAM actually uses a different, high resolution, in house SST product. Furthermore, the ECMWF deterministic (15km) model is NOT dynamically coupled to an ocean general circulation model (OGCM). The deterministic ECMWF is dynamically coupled to a wave model, which is NOT the same as and OGCM. Only their long range ensembles are coupled to an interactive ocean model....from their ensemble documentation: "Forecasts are run with with persisted SST anomalies from day 0 to day 10, and with coupled ocean model from day 10 to day 15. On Mondays and Thursdays, the 00 UTC forecasts are extended to day 32." Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 31, 2013 Share Posted December 31, 2013 Nice oes signal on the models. Check out the hi res stuff......nice signal indeed which may considerably enhance amounts for the shore areas and Boston metro. Don't worry, that is a cetainty This system is a dead ringer for that. GL. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted December 31, 2013 Share Posted December 31, 2013 Pump the brakes a little? 20:1 is awfully rare for an event in SNE. Not in BOS, but ORH and BDL with temps near 0 would be close Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted December 31, 2013 Share Posted December 31, 2013 The RGEM has been remarkable but thats inside 36 hours, the GGEM I thought has been bad beyond 48 and good inside 48...I've noticed the GGEM as I posted earlier overplays its hand given where most guidance is, if we're looking at a close in closed off system its west of everything, if we have a less phased system its always the most progressive. Gotcha...that sounds about right. Isn't the RGEM essentially the "GGEM" inside of 48 anyway? I'd read in the past that the CMC folks had said to use the RGEM inside of 48 vs the GGEM but maybe that is an urban legend. Link to comment Share on other sites More sharing options...
OceanStWx Posted December 31, 2013 Share Posted December 31, 2013 In his defense we did a 30-1 day in December already, Boston is probably not a spot being on the water you would get high ratios too often The point isn't that it can't happen, it's that it's rare to maintain it for an entire event. Banking 20:1 ratios on all 0.75" QPF the GFS has isn't the best way to go about forecasting your snow total in CT. Link to comment Share on other sites More sharing options...
Typhoon Tip Posted December 31, 2013 Author Share Posted December 31, 2013 Yeah ...well, like I and perhaps a few others tried to hammer out across the last two days, is you'd probably be better off as winter weather enthusiasts and/or OCD snow geese if you tempered your enthusiasm for this particular event -- and why. Pros: the impulse(s) responsible for this are just now relaying off the GOA into B.C. in western Canada. As NCEP had previously noted ... data dearth in the erstwhile time frames "might" not have lent too well to deterministic outcomes down stream of eastern N/A, where/when they encounter the possibility for L/W constructive interference/amplitude ....which brings up an opportunity for a con Cons: height are modeled too high, and the balanced geostrophic wind is too strong in the SE associated with compressed/flattened SW Atlantic Basin ridging. That is a "deconstructive" wave interference. Jet wind maxes that define the amplitude of impulses become less capable of initiating cyclogenesis, for basic mechanical reasoning surrounding thus made weak delta(V)s. Pro/Con is this convective feedback that appears evident. In a transitive sense, it appears that the weaker impulse scheme is partially the cause of that convection. If cyclogenesis were stronger, sooner, than the models might have less latent heat to dump into convection ... which then go on to creating phantom v-maxes and mass-balanced lower pressure nodes. You know...in way, because these models do not have a very "correct" parameterization, when they do that, the entire surrounding medium has to then adjust to conserve mass and motion everywhere to accommodate the presence of these engineered features. So in effect, these models are feed-back chaos engines. That really could get one into a sticky philosophical discussion surrounding man-made-modeled fractals -vs- those that occur as emergent processes in nature (thus real). The real disconnect in forecasting accuracy probably starts there, stopping man-made chaos, then, figuring out how to determine when/where the natural ones will take place. Eventually machine intelligence(s) would be invented that could then control when/where, and ...eeew. By then ...we'll be gods. But I digress. Can you imagine a future horror where the weather is entirely controlled? Unless a terror organization infiltrated the NCEP head-quarters where the "Weather Modification Net" is operated, I suspect in very high likelihood that weather becomes an affair of persistent quiescence, where the only excitement there would be are the planned 5pm light rain showers that lubricates farming, or the planned light to moderate snows, overnight, for the ski-industries, or the planned cloud cover to control global albedo. But lightning strikes on a soccer fields, wind-downed trees over powerlines, society haulting snow storms, flash floods, hurricanes impacting ...anyone, no tornadoes, all of it, a thing of the past in a weather-controlled "utopia." The irony being, for some small fraction of the population, removing the drama of the uncertainty in weather, and big natural events would be quite the opposite: it would be a dystopian rule. Where in f was going with this ... oh yeah, as more dynamics get relayed in during the day, the grids (according to NCEP -- don't blow flame at me because you might be one of those types that roll eyes at data sparseness; I'm just the messenger) may beef up with better density, and we'll see. I did notice a very subtle increased DPVA signature SE of the Cape with this 12z oper. GFS (I think Will or Scott might have noticed that too) despite the overall, general impact being essentially the same. I still see, however, that the GFS has convectively sheared (developed a convective induced low that strips a lot of instability and dynamics "perhaps" prematurely seaward) the system still. Again, what really needs to happen is the diving impulse down the eastern Rockies/Plains needs to initiate primary cyclogenesis faster and stronger (prior to Miller-B transition), such that there is less dynamics laying around for phantom convection to noise-up the playing field. Perhaps now-casting what is being relayed off the Pac is a way to go... Might be time to go read the model diagnostic comments. In ending I will say ... I was impressed to see the king James bible model, the Euro, show discontinuity inside of a 4-day foresight. That's no success for that model in my opinion and it seeing as that tool comes along with a certain proven standard of excellence, it gets a dink in its reputation armor for that. How much remains to be seen. If it all comes back on board, than it gets a pass, as a "glitch" run -- whatever that means. Link to comment Share on other sites More sharing options...
Ginx snewx Posted December 31, 2013 Share Posted December 31, 2013 -ish. That's close enough for the sake of argument. To clarify earlier discussion, the lower boundary condition I was quoted on earlier is only relevant to the GFS. The NAM actually uses a different, high resolution, in house SST product. Furthermore, the ECMWF deterministic (15km) model is NOT dynamically coupled to an ocean general circulation model (OGCM). The deterministic ECMWF is dynamically coupled to a wave model, which is NOT the same as and OGCM. Only their long range ensembles are coupled to an interactive ocean model....from their ensemble documentation: "Forecasts are run with with persisted SST anomalies from day 0 to day 10, and with coupled ocean model from day 10 to day 15. On Mondays and Thursdays, the 00 UTC forecasts are extended to day 32." Thanks for the clarification. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 31, 2013 Share Posted December 31, 2013 Not in BOS, but ORH and BDL with temps near 0 would be close Surface temps have little to do with ratios. Man, huge misconception. Link to comment Share on other sites More sharing options...
OceanStWx Posted December 31, 2013 Share Posted December 31, 2013 Not in BOS, but ORH and BDL with temps near 0 would be close You're missing the point. This isn't for BOS specifically, it's for the entire CWA. The above figures represent a 30 year climatology of snow to liquid ratios that was compiled using NWS Cooperative Observer Summary of the Day data. Only snowfalls greater than 2" and liquid equivalents greater than 0.11" were included. Events estimated by NCDC were discarded. A station must have recorded at least 15 observations over the 30 year period to be included. The total number of stations included was 7760. Portions of the maps with no analysis contain no data for that grid point. Link to comment Share on other sites More sharing options...
Ginx snewx Posted December 31, 2013 Share Posted December 31, 2013 The point isn't that it can't happen, it's that it's rare to maintain it for an entire event. Banking 20:1 ratios on all 0.75" QPF the GFS has isn't the best way to go about forecasting your snow total in CT.Lol of course but having seen a few one can hope. Link to comment Share on other sites More sharing options...
dendrite Posted December 31, 2013 Share Posted December 31, 2013 No, not at all, but seems a little extreme for 14-16+, no? MOS doesn't have that though. Will was just giving an example. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted December 31, 2013 Share Posted December 31, 2013 That post took up almost a whole page Link to comment Share on other sites More sharing options...
Damage In Tolland Posted December 31, 2013 Share Posted December 31, 2013 Surface temps have little to do with ratios. Man, huge misconception. When it's frigid from the top down like in this rare setup we have they do Link to comment Share on other sites More sharing options...
CT Rain Posted December 31, 2013 Share Posted December 31, 2013 Surface temps have little to do with ratios. Man, huge misconception. Yup one of my biggest pet peeves. Link to comment Share on other sites More sharing options...
weatherMA Posted December 31, 2013 Share Posted December 31, 2013 hey Jerry - what do 1/2/4/6/8 mean. I just ran them for various locations. For Instance, I see ORH has a 6 for hr 72 and an 8 for hr 96. Thanks! MOS doesn't have that though. Will was just giving an example. Ok, thanks. The post above seemed to imply that it did, that's all. Sorry for the confusion. Link to comment Share on other sites More sharing options...
OceanStWx Posted December 31, 2013 Share Posted December 31, 2013 Lol of course but having seen a few one can hope. One NE of BDL can hope. Link to comment Share on other sites More sharing options...
ineedsnow Posted December 31, 2013 Share Posted December 31, 2013 well whatever happens with this storm it will be damn cold after... This is for International Falls tonight we will see this in a modified form.. TonightPartly cloudy, with a low around -41. Northwest wind around 5 mph becoming calm. Link to comment Share on other sites More sharing options...
dendrite Posted December 31, 2013 Share Posted December 31, 2013 When it's frigid from the top down like in this rare setup we have they do 2m temps matter for ratios? How much saturated lift are you getting at your Davis level? Link to comment Share on other sites More sharing options...
bobbutts Posted December 31, 2013 Share Posted December 31, 2013 Kevin Skarupa talking about fluff factor and long duration and he wants to see the Euro edit oh cool, wmur lets you embed their video now, used to be forbidden Link to comment Share on other sites More sharing options...
OceanStWx Posted December 31, 2013 Share Posted December 31, 2013 When it's frigid from the top down like in this rare setup we have they do You can pelt ZR at 15 in South County RI, if it's warmer aloft it's warmer aloft. I think the profile will be very conducive to high ratio snow for some of the event. I'm just saying wall to wall 20:1 is unlikely. We will see the warm nose outside of the ideal snow growth zone for a time in SNE. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 31, 2013 Share Posted December 31, 2013 When it's frigid from the top down like in this rare setup we have they do No, its all how strong, and well alighned the lift is with the snowgrowth region....and how saturated the SG region is. Extremely cold, dry air masses can actually impede ratios in extreme instances. Link to comment Share on other sites More sharing options...
Ginx snewx Posted December 31, 2013 Share Posted December 31, 2013 You're missing the point. This isn't for BOS specifically, it's for the entire CWA.that info would have been helpful with your first post. I am convinced that ratios will be higher than 10-1, that's all I can say Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted December 31, 2013 Share Posted December 31, 2013 12z GEFS were actually a little dryer than the 0z in the 72 vs 84 hour timeframe the further NW you go in NE. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted December 31, 2013 Share Posted December 31, 2013 You can pelt ZR at 15 in South County RI, if it's warmer aloft it's warmer aloft. I think the profile will be very conducive to high ratio snow for some of the event. I'm just saying wall to wall 20:1 is unlikely. We will see the warm nose outside of the ideal snow growth zone for a time in SNE.Yeah I didn't mean for the entire 2 day event. But there will be a time period where we'll have some ratios close to that interior Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 31, 2013 Share Posted December 31, 2013 2m temps matter for ratios? How much saturated lift are you getting at your Davis level? I agree that when the BL is like 34*, it can hurt....but that factor as a whole is vastly overplayed. Link to comment Share on other sites More sharing options...
OceanStWx Posted December 31, 2013 Share Posted December 31, 2013 that info would have been helpful with your first post. I am convinced that ratios will be higher than 10-1, that's all I can say Sorry, I thought people would see the map and think Boston CWA. I realized that after the fact and added the SLU disclaimer for clarification. And as I stated, I think we're primed for higher ratios too. I just don't think going wall to wall 20:1 is going to be the true outcome. Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 31, 2013 Share Posted December 31, 2013 I think a much safer bet will be to assume an average of a 15:1 ratio, thus .75" of QPF may yield a nice, fluffy 10"+ event.... Link to comment Share on other sites More sharing options...
OceanStWx Posted December 31, 2013 Share Posted December 31, 2013 I think a much safer bet will be to assume an average of a 15:1 ratio, thus .75" of QPF may yield a nice, fluffy 10"+ event.... Event average, that seems pretty reasonable. That's how 10-12+ becomes 14-16+. Big difference for the weenies. Link to comment Share on other sites More sharing options...
weatherMA Posted December 31, 2013 Share Posted December 31, 2013 I think a much safer bet will be to assume an average of a 15:1 ratio, thus .75" of QPF may yield a nice, fluffy 10"+ event.... Right...and the long duration aspect might lead to 7-8 actual snow OTG, post-storm. Link to comment Share on other sites More sharing options...
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