Edge Weather Posted March 24, 2014 Share Posted March 24, 2014 Ensemble member #46 has 10"+ from DC to Boston. Ensemble member #48 has 10"+ from BWI to Cape Cod Plenty of members have 6"+ over a large area. Hence the WPC map posted earlier. It is still remotely possible the primary low could form near Cape Hatteras and remain the predominant storm, but it is a long shot. But the ensembles show it is not impossible. The low does not even form for another 24 hours. Link to comment Share on other sites More sharing options...
MJO812 Posted March 24, 2014 Share Posted March 24, 2014 That's impressive . That goes to show you that this storm is still up in the air. Link to comment Share on other sites More sharing options...
IsentropicLift Posted March 24, 2014 Share Posted March 24, 2014 That's impressive . That goes to show you that this storm is still up in the air. I expected to see all of the ensembles tightly clustered around the mean at this close range, as you can see, far from the case. Link to comment Share on other sites More sharing options...
ag3 Posted March 24, 2014 Share Posted March 24, 2014 12z Rgem is maybe 1-2mm of precip, based on the black and whites. It does try and also develop the double low closer to the coast, but not enough to impact the area. Link to comment Share on other sites More sharing options...
GD0815 Posted March 24, 2014 Share Posted March 24, 2014 That's impressive . That goes to show you that this storm is still up in the air. When a storm is this close in range, you really don't want to hang your hat on ensembles. You have model after model with higher resolution telling you this is a miss. Link to comment Share on other sites More sharing options...
IsentropicLift Posted March 24, 2014 Share Posted March 24, 2014 Using KMMU as a reference point since it's pretty far NW, 23 out of 51 members have at least 2" of snow. Only two members have 0.00" That number increases to 27/51 at KLGA. Still some sizeable hits mixed in with 7 members showing 6"+ at KLGA. Link to comment Share on other sites More sharing options...
JC-CT Posted March 24, 2014 Share Posted March 24, 2014 When a storm is this close in range, you really don't want to hang your hat on ensembles. You have model after model with higher resolution telling you this is a miss. You still look to them for sensitivity level and spread. Link to comment Share on other sites More sharing options...
Brian5671 Posted March 24, 2014 Share Posted March 24, 2014 That's impressive . That goes to show you that this storm is still up in the air. Not it's not. It's a miss for most outside of far SE NE. Guidance is in fairly strong agreement of that 24 hrs out right now Link to comment Share on other sites More sharing options...
Juliancolton Posted March 24, 2014 Share Posted March 24, 2014 When a storm is this close in range, you really don't want to hang your hat on ensembles. You have model after model with higher resolution telling you this is a miss. Yeah, I've always been cautioned to start weaning off the ensemble systems within 48 hours. I guess you could still justify using ensemble means, but nitpicking the individual members this close in seems like an unholy degree of grasping at straws. Link to comment Share on other sites More sharing options...
GD0815 Posted March 24, 2014 Share Posted March 24, 2014 You still look to them for sensitivity level and spread. sure, to some extent, but I dont think it is fair to characterize this storm as up in the air. Link to comment Share on other sites More sharing options...
IsentropicLift Posted March 24, 2014 Share Posted March 24, 2014 Goes from 990mb To 958mb 12 hours later! Link to comment Share on other sites More sharing options...
JC-CT Posted March 24, 2014 Share Posted March 24, 2014 Not it's not. It's a miss for most outside of far SE NE. Guidance is in fairly strong agreement of that 24 hrs out right now How do you figure we are 24 hours out? Link to comment Share on other sites More sharing options...
IsentropicLift Posted March 24, 2014 Share Posted March 24, 2014 Not it's not. It's a miss for most outside of far SE NE. Guidance is in fairly strong agreement of that 24 hrs out right now The only strong agreement here is that it's still a miss. The exact track is far from being nailed down. Link to comment Share on other sites More sharing options...
MJO812 Posted March 24, 2014 Share Posted March 24, 2014 Not it's not. It's a miss for most outside of far SE NE. Guidance is in fairly strong agreement of that 24 hrs out right now A miss for a big storm but not a miss just yet for maybe a few inches. Link to comment Share on other sites More sharing options...
IsentropicLift Posted March 24, 2014 Share Posted March 24, 2014 Ignore the ECMWF ensembles at your own risk. this isn't a case where the mean is being skewed by a few west members. It's almost a 50/50 split. Link to comment Share on other sites More sharing options...
Ed Lizard Posted March 24, 2014 Share Posted March 24, 2014 When a storm is this close in range, you really don't want to hang your hat on ensembles. You have model after model with higher resolution telling you this is a miss. One assumes the op was initialized with data as good as possible, the ensembles account for inherent uncertainty in the intialization. Possible the ensemble run that bombs your house was perturbed in such a way as to best really represent the initial conditions, if enough of them show it , might mean something is still possible, if 2 or 3 out of 50 show it, implies a 4 or 6% chance, in a way (may not be rigorously correct) at best the op is wrong and the happiest ensemble is correct. Ensemble forecasting, as is often noted, is best for longer range trends than 2 day before the storm pick a pertuabation you like and run with it forecasting. Said as a NYC phasing/complex Winter storm modelologist, who doesn't have the training or time to get deeper into the actual meteorology involved, I try harder for severe and tropical, they still require some modelology for forecasting more than a very short time out, but I can actually get a feel for whether even a usually reliable model is missing something. Not so with complex NW snowstorms. Link to comment Share on other sites More sharing options...
JC-CT Posted March 24, 2014 Share Posted March 24, 2014 Ignore the ECMWF ensembles at your own risk. this isn't a case where the mean is being skewed by a few west members. It's almost a 50/50 split. As well as the WPC and NWS. Link to comment Share on other sites More sharing options...
IsentropicLift Posted March 24, 2014 Share Posted March 24, 2014 Look at that buckling in the 500mb flow over North Carolina. Link to comment Share on other sites More sharing options...
IsentropicLift Posted March 24, 2014 Share Posted March 24, 2014 Yet 12 hours later this happens. Link to comment Share on other sites More sharing options...
monmouthcounty11 Posted March 24, 2014 Share Posted March 24, 2014 12z RGEM is a little west of the 6z and 0z runs. It looks like it keeps the low that is closer to coast around a little longer, it's still a miss for all intents and purposes though. Link to comment Share on other sites More sharing options...
nyblizz44 Posted March 24, 2014 Share Posted March 24, 2014 What is absolutely critical is what is happening between hrs 33 and 39. There are two jet streaks. The first of which is more vigorous and allows for the development of the first surface cyclone that heads further east. The second low forms as a result of a second jet streak, coming behind, over the Carolinas - this is the one we want to predominate. The first low, in my opinion is in a less favorable baroclinic zone (the gulf stream in mind), but gets going earlier, and the cold/warm air advections shift the baroclinic zone such that the second low is in a relatively less favorable pressure fall (surface convergence) zone. To be honest, I think the second low overall is the more favorable one, in terms of dynamics, despite the evolution of this setup. It is very close in my opinion, and it's something to watch very carefully. That wording, carefully done obviously, indicates you think there is an outside chance the models are focuing on the wrong low & that the correct one may very well turn out to be the 1 closer to the coast? Link to comment Share on other sites More sharing options...
Ed Lizard Posted March 24, 2014 Share Posted March 24, 2014 In December or January, with minimal snow angle and temps not too far above freezing, 0.2 inches in 6 or 12 hours may be an accumulating snow, past the Equinox, that is flakes that melt on contact. Below freezing, maybe flakes that stick to grassy surfaces, best I can tell. Link to comment Share on other sites More sharing options...
monmouthcounty11 Posted March 24, 2014 Share Posted March 24, 2014 Precip accum on the RGEM: 12z: 6z: Link to comment Share on other sites More sharing options...
IsentropicLift Posted March 24, 2014 Share Posted March 24, 2014 The 12z GFS sends the first low to Bermuda! Link to comment Share on other sites More sharing options...
Brian5671 Posted March 24, 2014 Share Posted March 24, 2014 A miss for a big storm but not a miss just yet for maybe a few inches. first of all, you are not seeing a few inches. second of all, even if that fell, you might see a slushy inch or so on colder surfaces--rates are not heavy enough. Link to comment Share on other sites More sharing options...
alwaysready126 Posted March 24, 2014 Share Posted March 24, 2014 to me, and I'm no expert by any means, despite not too many runs showing a significant hit, it seems if we can get that trough to go negative by the slightest amount, we have an entirely different ballgame. I'm not saying it will happen, nor do I have any evidence to suggest that it might. Maybe someone who knows more than me can comment as to the probability of that happening. Link to comment Share on other sites More sharing options...
IsentropicLift Posted March 24, 2014 Share Posted March 24, 2014 GFS a tick west again, a few hours slower and a bit more intense. Link to comment Share on other sites More sharing options...
MJO812 Posted March 24, 2014 Share Posted March 24, 2014 The 12z GFS sends the first low to Bermuda! Then forms another low but the 1st one steals all the energy. We have to watch out for these lows and see what happens. first of all, you are not seeing a few inches. second of all, even if that fell, you might see a slushy inch or so on colder surfaces--rates are not heavy enough. Did the storm even happen? Link to comment Share on other sites More sharing options...
ag3 Posted March 24, 2014 Share Posted March 24, 2014 GFS a tick west again, a few hours slower and a bit more intense. It's more then a tick. Pretty good move west here. Not enough for our area, but definitely enough to check out the 0z runs tonight. Link to comment Share on other sites More sharing options...
Weathergun Posted March 24, 2014 Share Posted March 24, 2014 The 12z GFS forms the second low. But it's kicked east again. The second low really benefits more people to the south along the coast. All the upper-level jet supports shifts east after that. 5H Vorticity also shoots too far underneath us. Link to comment Share on other sites More sharing options...
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