IsentropicLift Posted February 9, 2014 Share Posted February 9, 2014 Yea thats a pretty nice shift The 0.75"+ line shifted over 50 miles NW. Link to comment Share on other sites More sharing options...
JetsPens87 Posted February 9, 2014 Share Posted February 9, 2014 The southern vort should be onshore by the 12z runs tomorrow. Hopefully once the models are able to get a better handle on the strength of this vort we'll get closer to a consensus. Absolutely, as much a key to this as the GL disturbance is, the strength of the southern vort is as important. The stronger it is, the more it can pump heights ahead of it giving it a much better chance to turn the corner. Link to comment Share on other sites More sharing options...
rsteff Posted February 9, 2014 Share Posted February 9, 2014 It can be a bad thing or a good thing ( I know this sounds so cliché) But watch/read/participate in the discussion between Earthlight and myself and others about this feature as to how it may eventually affect the outcome of this system as this is currently what we are keying in on as a major player. I am thinking we will need a very dynamic strong costal and a weak lakes slp to keep snow at the coast Link to comment Share on other sites More sharing options...
earthlight Posted February 9, 2014 Share Posted February 9, 2014 Let's play a little what if, since this is such an intricate setup in so many varying ways. If the GFS were as strong with the southern vort as the NAM what do you think the downstream effects would be then? (Using the same position of the GL disturbance as the GFS currently has). Maybe a situation where you'd have a coastal bomb but the GL disturbance pushes back on the dynamics on the NWRN side of the precip shield similar to ggem? I think it probably would end up similar to the more wrapped up globals, yes. But these type of differences are probably going to continue to show themselves until the features of importance get into more dense data ingestion regions. Speaking of which, the GEFS mean looks good but the individuals are all over the place. None of them really resulting in an ideal solution here. Some are wrapped up and warm, others are strung out and east. http://www.meteo.psu.edu/~fxg1/ENSPRSNE_18z/f96.gif Link to comment Share on other sites More sharing options...
Heisy Posted February 9, 2014 Share Posted February 9, 2014 Yea the GEFS mean is kind of a mirage, none of the individuals show that good of a result....I've been saying personally I would expect the GFS to take a big step towards the EURO in its 72 hour wheelhouse. Around 12z tomorrow we should see a significant jump IMO. Yanks, remember the DGEX is just a continuation of the 84 HR NAM. The NAM is doing its ol' 2 low thing it does a lot before big storms. Ignore it. Link to comment Share on other sites More sharing options...
JetsPens87 Posted February 9, 2014 Share Posted February 9, 2014 Yea the GEFS mean is kind of a mirage, none of the individuals show that good of a result....I've been saying personally I would expect the GFS to take a big step towards the EURO in its 72 hour wheelhouse. Around 12z tomorrow we should see a significant jump IMO. Yanks, remember the DGEX is just a continuation of the 84 HR NAM. The NAM is doing its ol' 2 low thing it does a lot before big storms. Ignore it. But then again, that is what we have the mean for, smoothing the differences between the initial atmospheric conditions that each ensemble member portrays. So while no individual member shows what the mean shows, it does not necessarily mean that the mean is not plausible. In fact, if each member portrays a different perturbation in initial conditions, and the mean averages all of them, in theory the mean should be more accurate then any individual member. It is the case of the whole is greater then the sum of the parts theory. Link to comment Share on other sites More sharing options...
Heisy Posted February 9, 2014 Share Posted February 9, 2014 But then again, that is what we have the mean for, smoothing the differences between the initial atmospheric conditions that each ensemble member portrays. So while no individual member shows what the mean shows, it does not necessarily mean that the mean is not plausible. In fact, if each member portrays a different perturbation in initial conditions, and the mean averages all of them, in theory the mean should be more accurate then any individual member. It is the case of the whole is greater then the sum of the parts theory. Interesting, thanks! Didn't think of it that way. Link to comment Share on other sites More sharing options...
rsteff Posted February 9, 2014 Share Posted February 9, 2014 But then again, that is what we have the mean for, smoothing the differences between the initial atmospheric conditions that each ensemble member portrays. So while no individual member shows what the mean shows, it does not necessarily mean that the mean is not plausible. In fact, if each member portrays a different perturbation in initial conditions, and the mean averages all of them, in theory the mean should be more accurate then any individual member. It is the case of the whole is greater then the sum of the parts theory. Sort of the best straight line algorithm Link to comment Share on other sites More sharing options...
JetsPens87 Posted February 10, 2014 Share Posted February 10, 2014 I'm a lurker ... greatly appreciate all the insights I read. One question re: the mean. Wouldn't the standard deviation also be relevant in determining how the mean is viewed? Well the mean is all the different members averaged together. The standard deviation would be relevant in looking at how far from normal conditions the mean is forecasted. But in and of itself I'm not sure if I'm clear on where you are asking the SD comes into play. Could you clarify so that I could provide a better answer? Link to comment Share on other sites More sharing options...
kpantz Posted February 10, 2014 Share Posted February 10, 2014 Well the mean is all the different members averaged together. The standard deviation would be relevant in looking at how far from normal conditions the mean is forecasted. But in and of itself I'm not sure if I'm clear on where you are asking the SD comes into play. Could you clarify so that I could provide a better answer? I think it's related to spread in our terminology, right? So, the greater the spread, the greater the standard deviation you'd calculate, which - in my mind - equates to variability and volatility of the individual members' solutions. If the mean is a 960mb low 75 mi E of ACY, but the spread is monstrous, it would imply that members are sending the low to Chicago and to Bermuda. In other words, low confidence. Link to comment Share on other sites More sharing options...
RU848789 Posted February 10, 2014 Share Posted February 10, 2014 Let's play a little what if, since this is such an intricate setup in so many varying ways. If the GFS were as strong with the southern vort as the NAM what do you think the downstream effects would be then? (Using the same position of the GL disturbance as the GFS currently has). Maybe a situation where you'd have a coastal bomb but the GL disturbance pushes back on the dynamics on the NWRN side of the precip shield similar to ggem? Great last few pages with some awesome input from the pros. Question, based on your "what if" scenario: is there any capability to run what I'd call "future state ensembles," i.e., running the GFS ensembles out 24 hours and taking the ensemble run with the strongest southern vort on the GFS (as you suggested in your what if) and then inputting a new set of "initial conditions 24 hours out" and then letting the run go out a few days, just to see if one would end up with a new "future ensemble mean" that is similar to the NAM (or some other model) at 84 hours? Not sure what that would show with regard to the actual reality of what will happen, but it would be at least interesting to see if different models with similar starting points (24 hours into the future) would produce similar output at, say 84 hours. Link to comment Share on other sites More sharing options...
JetsPens87 Posted February 10, 2014 Share Posted February 10, 2014 I think it's related to spread in our terminology, right? So, the greater the spread, the greater the standard deviation you'd calculate, which - in my mind - equates to variability and volatility of the individual members' solutions. If the mean is a 960mb low 75 mi E of ACY, but the spread is monstrous, it would imply that members are sending the low to Chicago and to Bermuda. In other words, low confidence. Ah yes, that would make sense taking the spread into account, much like when you look at the SREF spreads. Once the SD shrinks the confidence goes up. Thank you. Hopefully that answers Yankees29's question. Link to comment Share on other sites More sharing options...
JetsPens87 Posted February 10, 2014 Share Posted February 10, 2014 Great last few pages with some awesome input from the pros. Question, based on your "what if" scenario: is there any capability to run what I'd call "future state ensembles," i.e., running the GFS ensembles out 24 hours and taking the ensemble run with the strongest southern vort on the GFS (as you suggested in your what if) and then inputting a new set of "initial conditions 24 hours out" and then letting the run go out a few days, just to see if one would end up with a new "future ensemble mean" that is similar to the NAM (or some other model) at 84 hours? Not sure what that would show with regard to the actual reality of what will happen, but it would be at least interesting to see if different models with similar starting points (24 hours into the future) would produce similar output at, say 84 hours. Unfortunately it is difficult enough to try and run numerical models based on current initial atmospheric states as is (hence exactly why we use ensembles). I do not know of any research efforts being done into running models with initial conditions anticipated 24 hours out in advance. However, I am assuming that some of the ensembles are running initial states currently that are taking into account different perturbations in that GL disturbance as is that would theoretically have the downstream influences on it that we are hoping to look for. Link to comment Share on other sites More sharing options...
PB GFI Posted February 10, 2014 Share Posted February 10, 2014 Ah yes, that would make sense taking the spread into account, much like when you look at the SREF spreads. Once the SD shrinks the confidence goes up. Thank you. Hopefully that answers Yankees29's question. I have to imagine there`s a more narrow spray on the Euro ensembles , this look has been quasi pinned here for 4 days . There`s been very little variance . Don't think its the foul pole to foul pole spread on the Euro Link to comment Share on other sites More sharing options...
JetsPens87 Posted February 10, 2014 Share Posted February 10, 2014 I have to imagine there`s a more narrow spray on the Euro ensembles , this look has been quasi pinned here for 4 days . There`s been very little variance . Don't think its the foul pole to foul pole spread on the Euro I have to imagine there`s a more narrow spray on the Euro ensembles , this look has been quasi pinned here for 4 days . There`s been very little variance . Don't think its the foul pole to foul pole spread on the Euro Which is why I'm currently using the euro ensembles as my guidance of choice right now. Moreso then anything, I enjoy consistency in guidance when I'm forecasting. The ensembles have been steadfast in their handling of all the major players on the field. Since the southern stream has come into play the euro has really picked up its game over the GFS (which to its credit held the edge earlier in the season when it was northern stream dominated). Much of the time when guidance is flip-flopping it is not necessarily because all of a sudden the model thinks a SLP is going OTS versus cutting inland but moreso because there is some other feature upstream in the flow that it is having trouble with. It is the lack of consistency in these features that often have huge implications in the end result. I love making quirky analogies so this would be the case of killing a butterfly in the past would cause worldly changes in the future scenario. In the instance of our storm the features that the models are having trouble with are the strength of the southern vort and placement/strength/movement of the GL disturbance. TINY changes in these will have HUGE implications in the end result of our storm. SO major flip flops in guidance may result from just tiny perturbations in the flow of these events and features, which is why im choosing to ride the steady hand with the euro ensembles right now since they seem to be most consistent on their handling of major players on the field. Link to comment Share on other sites More sharing options...
PB GFI Posted February 10, 2014 Share Posted February 10, 2014 Which is why I'm currently using the euro ensembles as my guidance of choice right now. Moreso then anything, I enjoy consistency in guidance when I'm forecasting. The ensembles have been steadfast in their handling of all the major players on the field. Since the southern stream has come into play the euro has really picked up its game over the GFS (which to its credit held the edge earlier in the season when it was northern stream dominated). Think the Euro struggled with a NEG EPO dominated regime , and the GFS really beat it in the Northern branch . But yes its been pinned here . I look at this as a 3 day away feature , because if the Euro can get me to OBX and settle the speed of the SLP in the GLC , then it will come . Link to comment Share on other sites More sharing options...
Allsnow Posted February 10, 2014 Share Posted February 10, 2014 SREFS are a mecs….pretty nice Link to comment Share on other sites More sharing options...
Doorman Posted February 10, 2014 Share Posted February 10, 2014 Even with a 96hr ETA for this system, the polar jet stream set-up has some moxy (cold pool) to work with the loop just grabs me http://weather.cod.edu/satrad/ Link to comment Share on other sites More sharing options...
Stormlover74 Posted February 10, 2014 Share Posted February 10, 2014 I heard the analog the wpc is using is 1/22/87...that was a 10-11" thump here Link to comment Share on other sites More sharing options...
jm1220 Posted February 10, 2014 Share Posted February 10, 2014 Even with a 96hr ETA for this system, the polar jet stream set-up has some moxy (cold pool) to work with the loop just grabs me The high and cold source lifts out as the storm gets going. The Euro holds it in a little longer and generates cold on the west side of the storm via rapid cyclogenesis. But we're really relying on good timing and circumstances with phasing to have a good result here. Link to comment Share on other sites More sharing options...
IntenseBlizzard2014 Posted February 10, 2014 Share Posted February 10, 2014 I heard the analog the wpc is using is 1/22/87...that was a 10-11" thump here It's good, but the storm happening this week will clearly have more moisture involved. That analogue could have half way figured out the scenario. Link to comment Share on other sites More sharing options...
Superstorm93 Posted February 10, 2014 Share Posted February 10, 2014 21z SREF Link to comment Share on other sites More sharing options...
+SNfreak21 Posted February 10, 2014 Share Posted February 10, 2014 1/25/00 is a good analog IMO Link to comment Share on other sites More sharing options...
IntenseBlizzard2014 Posted February 10, 2014 Share Posted February 10, 2014 I'm surprised no one said that the 18Z DGEX has 10-15" of snow for the Tri State Area. With 15"+ of snow at SE Mass. Link to comment Share on other sites More sharing options...
IntenseBlizzard2014 Posted February 10, 2014 Share Posted February 10, 2014 1/25/00 is a good analog IMO If it weren't for the HP over the Upper Midwest, this would've been perfect. Otherwise, very good analogue. Link to comment Share on other sites More sharing options...
Stormlover74 Posted February 10, 2014 Share Posted February 10, 2014 If it weren't for the HP over the Upper Midwest, this would've been perfect. Otherwise, very good analogue. We got dryslotted big time during that one Link to comment Share on other sites More sharing options...
Heisy Posted February 10, 2014 Share Posted February 10, 2014 I was going to post 1/25/00 just based on the H5 setup on the conus, its a delicate balance with the GL low and the southern vort, going to be a long few days Link to comment Share on other sites More sharing options...
jm1220 Posted February 10, 2014 Share Posted February 10, 2014 I'm surprised no one said that the 18Z DGEX has 10-15" of snow for the Tri State Area. With 15"+ of snow at SE Mass. DGEX is useless. Link to comment Share on other sites More sharing options...
weatherpruf Posted February 10, 2014 Share Posted February 10, 2014 I heard the analog the wpc is using is 1/22/87...that was a 10-11" thump here yikes that was an evil storm. Struck fast and at a bad time of day. people were stranded all over North Jersey; it also came in a mild decade so really no one was prepared. I got stuck in a Chevy Monza in that storm. Link to comment Share on other sites More sharing options...
IntenseBlizzard2014 Posted February 10, 2014 Share Posted February 10, 2014 DGEX is useless. I know, but it was brought up, so I thought someone would've said something about it. Link to comment Share on other sites More sharing options...
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