mappy Posted February 14, 2012 Share Posted February 14, 2012 Sweet. Looks like euro has my exact call There is still so much time for things to change. I think any guess and any model output at this range is very low confidence especially as to any specifics but even on the general track Adam said the key was up in Nova Scotia, if the low there is stronger it will flatten the jet across the mid-south and take the system OTS. If it is weaker and farther north, as the Euro is showing, it will create a temporary blocking pattern and will allow the system to gain latitude. He thinks there is too much that needs to come together right now for this to be a significant storm - but he also said there is not an insignificant chance that it could become something major for someone. Link to comment Share on other sites More sharing options...
am19psu Posted February 14, 2012 Share Posted February 14, 2012 Adam said the key was up in Nova Scotia, if the low there is stronger it will flatten the jet across the mid-south and take the system OTS. If it is weaker and farther north, as the Euro is showing, it will create a temporary blocking pattern and will allow the system to gain latitude. He thinks there is too much that needs to come together right now for this to be a significant storm - but he also said there is not an insignificant chance that it could become something major for someone. And by the bolded, I meant a KU-type storm Link to comment Share on other sites More sharing options...
mappy Posted February 14, 2012 Share Posted February 14, 2012 And by the bolded, I meant a KU-type storm Well Matt would know what I (you) meant. 2-4 inches though for the snow starved MA folks is significant, but yes... not KU significant. Link to comment Share on other sites More sharing options...
yoda Posted February 14, 2012 Share Posted February 14, 2012 And by the bolded, I meant a KU-type storm I figured you meant anything bigger than a 3 to 6/4 to 8 max storm Link to comment Share on other sites More sharing options...
Deck Pic Posted February 14, 2012 Share Posted February 14, 2012 Adam said the key was up in Nova Scotia, if the low there is stronger it will flatten the jet across the mid-south and take the system OTS. If it is weaker and farther north, as the Euro is showing, it will create a temporary blocking pattern and will allow the system to gain latitude. He thinks there is too much that needs to come together right now for this to be a significant storm - but he also said there is not an insignificant chance that it could become something major for someone. The pattern is lightning quick. I'm not that concerned about the low in Canada. It isn't a displaced stable feature. Link to comment Share on other sites More sharing options...
Benchmark Posted February 14, 2012 Share Posted February 14, 2012 Drool.... Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted February 14, 2012 Share Posted February 14, 2012 No real concensus gives you pause until you realize that this is still 5+ days away. Hopefully the GFS will start coming around to the Euro way of thinking. The HPC discussion is very positive IMO. COMING WEEKEND MODEL AND ENSEMBLE GUIDANCE DISPLAYS SIGNIFICANT SPREAD WITH RESPECT TO THE EVOLUTION OF AN EJECTING NWRN MEXICO CLOSED LOW AND POSSIBLE INTERACTING NRN STREAM ENERGY. THIS LEADS TO BELOW AVERAGE CONFIDENCE IN SPECIFICS OF CORRESPONDING SFC DEVELOPMENT AND SENSIBLE WEATHER IMPACT OVER AREAS FROM THE SRN PLAINS/GULF COAST NEWD THRU THE ERN CONUS. GIVEN THE PROGRESSIVE NATURE AND PACIFIC ORIGIN OF THE NRN STREAM ENERGY... IT MAY WELL TAKE UNTIL WITHIN A COUPLE DAYS OF ACTUAL SYSTEM DEVELOPMENT BEFORE SOME CONSENSUS EMERGES REGARDING IMPORTANT DETAILS. AMONG THE OPERATIONAL MODELS THE 00Z ECMWF CURRENTLY IS MOST AGGRESSIVE IN TERMS OF STRENGTH AND NWD/NEWD TRACK OF THE SFC LOW. THE 12Z/13 UKMET WAS FAIRLY SIMILAR TO THE 00Z ECMWF. THE 00Z GFS/UKMET/CMC HAVE MORE SUPPRESSED SOLNS TO VARYING DEGREES WHILE THE 06Z GFS SHOWS NO STREAM INTERACTION AND WEAKENS THE SRN STREAM FEATURE TO SUCH AN EXTENT THAT THE SFC WAVE DOES NOT SURVIVE PAST THE ERN GULF OF MEXICO. ENSEMBLES WIDEN THE SOLN ENVELOPE FURTHER... AS THE 00Z GEFS MEAN TRAILS THE SLOW SIDE OF THE OPERATIONAL SOLNS WHILE THE AVERAGE OF VARIED 00Z ECMWF ENSEMBLE MEMBERS YIELDS A WAVE FASTER THAN THE 00Z ECMWF. OVER THE PAST DAY THERE HAVE BEEN ENOUGH INDICATIONS FROM OPERATIONAL MODELS TOWARD AT LEAST A MODERATELY DEFINED SYSTEM... AND SUFFICIENT TROF AMPLIFICATION UPSTREAM TO SUGGEST A SFC TRACK SOMEWHAT NWD OF THE SRN SIDE OF THE SPREAD.. Link to comment Share on other sites More sharing options...
yoda Posted February 14, 2012 Share Posted February 14, 2012 S/W galore in the NE at 84 hrs on the 12z NAM at h5. Before you all say the usual, I am just looking at it to see where the major pieces are (mainly the 552 DM h5 low in the SW) and compare them with the GFS and EURO. Link to comment Share on other sites More sharing options...
RTutton Posted February 14, 2012 Share Posted February 14, 2012 S/W galore in the NE at 84 hrs on the 12z NAM at h5. Before you all say the usual, I am just looking at it to see where the major pieces are (mainly the 552 DM h5 low in the SW) and compare them with the GFS and EURO. Agreed, I like this look. Link to comment Share on other sites More sharing options...
MN Transplant Posted February 14, 2012 Share Posted February 14, 2012 S/W galore in the NE at 84 hrs on the 12z NAM at h5. Before you all say the usual, I am just looking at it to see where the major pieces are (mainly the 552 DM h5 low in the SW) and compare them with the GFS and EURO. If I take the NAM at 84, print it out and trace it with a little less resolution, I get the 06z GFS at 90. Link to comment Share on other sites More sharing options...
mitchnick Posted February 14, 2012 Share Posted February 14, 2012 Drool.... that's really not a lot of qpf all things considered maybe because it has it sliding east that DCA/BWI never gets under the really strong lift or lack of decent cold at the start whatever, I'm splitting hairs over a storm that is far from a lock Link to comment Share on other sites More sharing options...
yoda Posted February 14, 2012 Share Posted February 14, 2012 If I take the NAM at 84, print it out and trace it with a little less resolution, I get the 06z GFS at 90. Really? Well that sucks, cause the 06z GFS showed nothing at all in regards to a storm for anyone Link to comment Share on other sites More sharing options...
RTutton Posted February 14, 2012 Share Posted February 14, 2012 If I take the NAM at 84, print it out and trace it with a little less resolution, I get the 06z GFS at 90. Ya think? I see the southern s/w as healthier. At first glance the nothern impluses seem better but at second glance I guess you're right, they are similar. Link to comment Share on other sites More sharing options...
mitchnick Posted February 14, 2012 Share Posted February 14, 2012 keep in mind that the Euro, on at least 1 occasion and I believe more, had coastals this year and the GFS had nothing or had it and lost it first unless the MJO makes the difference this time, I think we should expect more of the same for the remainder of the season Link to comment Share on other sites More sharing options...
MN Transplant Posted February 14, 2012 Share Posted February 14, 2012 Ya think? I see the southern s/w as healthier. At first glance the nothern impluses seem better but at second glance I guess you're right, they are similar. It is, but how much of that has to do with resolution? Obviously no two runs are identical 3.5 days out, but as I was watching it come in, I was struck at how similar they looked when I toggled between the two. I don't want to say that the NAM supports the GFS's final solution, because frankly the Euro isn't shockingly different at that time frame either. Link to comment Share on other sites More sharing options...
usedtobe Posted February 14, 2012 Share Posted February 14, 2012 Are the wundermaps snow maps 3 hour accumulations? II kind of think they are but don't remember offhand. Link to comment Share on other sites More sharing options...
Porsche Posted February 14, 2012 Share Posted February 14, 2012 Are the wundermaps snow maps 3 hour accumulations? II kind of think they are but don't remember offhand. Yes they are Wes. Link to comment Share on other sites More sharing options...
Deck Pic Posted February 14, 2012 Share Posted February 14, 2012 I'd lean against suppression in this pattern with a GOM low. Doesn't mean the storm will hit us flush either. I think our biggest issue will be the air mass. But track and timing and amplification could help. We probably start as rain or a mix. But snow and 32-34 degrees is achievable with dynamics and timing and a good track. Link to comment Share on other sites More sharing options...
mitchnick Posted February 14, 2012 Share Posted February 14, 2012 Are the wundermaps snow maps 3 hour accumulations? II kind of think they are but don't remember offhand. up to and including the 144hrs map they are and then the next map, 150 hrs, they start 6 hr intervals until the last one at 180hrs Link to comment Share on other sites More sharing options...
mitchnick Posted February 14, 2012 Share Posted February 14, 2012 I'd lean against suppression in this pattern with a GOM low. Doesn't mean the storm will hit us flush either. I think our biggest issue will be the air mass. But track and timing and amplification could help. We probably start as rain or a mix. But snow and 32-34 degrees is achievable with dynamics and timing and a good track. if there's persistence in this pattern (and I'm not saying there is since we only have 1 southern storm to compare it to), we would see a similar result as this past weekend with the southern system taking over but just grazing us Link to comment Share on other sites More sharing options...
usedtobe Posted February 14, 2012 Share Posted February 14, 2012 up to and including the 144hrs map they are and then the next map, 150 hrs, they start 6 hr intervals until the last one at 180hrs Thanks, the two different time periods confused my old brain. Link to comment Share on other sites More sharing options...
Deck Pic Posted February 14, 2012 Share Posted February 14, 2012 if there's persistence in this pattern (and I'm not saying there is since we only have 1 southern storm to compare it to), we would see a similar result as this past weekend with the southern system taking over but just grazing us I think we would need timing for suppression so I would lean against it but it's just a guess. This past weekend I think we had a big vortex in southern Canada with a weak surface low in an unfavorable position to amplify. Link to comment Share on other sites More sharing options...
BristowWx Posted February 14, 2012 Share Posted February 14, 2012 While the general pattern is favorable for a mid-atlantic snowstorm (Southern Greenland Blocking / Slit Flow) there are a lot of s/w in play here and thats is going to significantly increase the uncertainty. With this caveat in mind, we are going to see huge short term changes in the storm track and intensity for the next 2-3 days before the solutions converge. However, I think the GFS has an increased probability to be wrong with the current storm evolution, mainly because it won't be able to properly handle the smaller scale features that will be pivotal to the following storms evolution. This doesn't only have to do with the GFS's poorer resolution in comparison to the ECMWF. The GFS also uses the leapfrog time step algorithm. This is important, because the main fallacy with the algorithm is that unless diffusion is applied for the first few time steps to dampen the higher frequency signals (smaller scale waves such as small shortwaves), the model will amplify features too quickly and cause the model to blow up or crash. While all models do apply some form of diffusion to handle poorly resolved waves, using this diffusion in tandem with the leapfrog method also sacrifices overall accuracy. My hunch is based on this knowledge. The GFS will tend to handle the overall pattern along with larger waves well, but its the small features (like what the ECMWF has been showing that will interact with the southern stream shortwave) that will make all the difference. If the GFS may not be able to model these waves to the same degree of accuracy as the ECMWF, then it makes more sense to believe a model that tends to have the higher accuracy. Another thing worth mentioning is that in general, models are generally too slow with the forward propagation of waves, which is why we so often see solutions bust on the slow side, even in the short term forecast. That is another thing that should be in the back of many peoples minds when trying to forecast shortwave evolution. Of course none of this means that we will see a huge snowstorm or even a storm at all. Its just in the overall scheme of things, the ECWMF will tend to have better resolved shortwave features in comparison to the GFS based on more than just higher resolution, and that the models as a whole tend to move waves too slowly (by a very small magnitude, but this can be amplified over time). Thank you. I had never heard that before and appreciate that kind of insight from a red tagger. Link to comment Share on other sites More sharing options...
Deck Pic Posted February 14, 2012 Share Posted February 14, 2012 Thanks for the info. I should add that to my untrained eye, I don't think in the euro depiction the northern stream was of much help. I think this storm can gain some latitude even without some ideal stream interaction. Link to comment Share on other sites More sharing options...
yoda Posted February 14, 2012 Share Posted February 14, 2012 So far... 12z GFS seems more compact and a tad stronger with the closed h5 low in the SW at 66 hrs, which is an improvement over the 06z h5 low at 72 Link to comment Share on other sites More sharing options...
yoda Posted February 14, 2012 Share Posted February 14, 2012 12z GFS has h5 energy in W TX/E MX at 96, which is faster than the 06z GFS had it way back in W MX at 102... only about a 200-300 mile difference AT 108 h5 energy in NE TX, big jump to the NE by about 300 miles over 06z GFS at the same time Link to comment Share on other sites More sharing options...
JMU2004 Posted February 14, 2012 Share Posted February 14, 2012 GFS has caved. Link to comment Share on other sites More sharing options...
yoda Posted February 14, 2012 Share Posted February 14, 2012 MUCH better h5 energy on the 12z run at 120 in W AL... 06z GFS had it washing out at 126 in LA... Link to comment Share on other sites More sharing options...
ravensrule Posted February 14, 2012 Share Posted February 14, 2012 GFS has caved. Hot like hell on the surface though. Link to comment Share on other sites More sharing options...
PhineasC Posted February 14, 2012 Share Posted February 14, 2012 Hot like hell on the surface though. It's really not that bad. Link to comment Share on other sites More sharing options...
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