tnweathernut Posted December 30, 2012 Share Posted December 30, 2012 As Briar mentioned earlier we probably won't know until around Tuesday when it can properly sample that energy in the north. This might be one of those painful ones where we're watching until the last minute. I wasn't impressed with the 12z runs, but as others have eluded to...........it wouldn't take much of a change with the northern stream to dramatically change the surface. Being the south, we will watch them ALL until the last minute. Link to comment Share on other sites More sharing options...
CAD_Wedge_NC Posted December 30, 2012 Share Posted December 30, 2012 Wouldn't a big phased storm pull the cold air down with it? Yes....a big phase would provide plenty of dynamic cooling on the west and northwest quadrants of the storm and it would pull down colder air into the storm. Link to comment Share on other sites More sharing options...
burgertime Posted December 30, 2012 Share Posted December 30, 2012 18z NAM at 54 is interesting at 5h. You've got that energy going into the baja coming really close to a phase with some energy diving into AZ. Link to comment Share on other sites More sharing options...
franklin NCwx Posted December 30, 2012 Share Posted December 30, 2012 It's interesting looking at the 6 hours euro frames, this is so close to a phased system similar to the christmas storm from 2 years ago. The pattern is almost identical.The models right now are racing the northern vort ahead of the southern vort. If the southern vort were to trend faster, you would see this northern vort fall in behind and cutoff into a phased system and lift the SLP from the GOM up the coast instead of out to sea. It's extremely similar scenario and the models could quickly change if they are just a bit off. I'm still very very interested in this one. Like the Ukie? Link to comment Share on other sites More sharing options...
tnweathernut Posted December 30, 2012 Share Posted December 30, 2012 As Briar mentioned earlier we probably won't know until around Tuesday when it can properly sample that energy in the north. This might be one of those painful ones where we're watching until the last minute. I wasn't impressed with the 12z runs, but as others have eluded to...........it wouldn't take much of a change with the northern stream to dramatically change the surface. Being the south, we will watch them ALL until the last minute. Link to comment Share on other sites More sharing options...
rduwx Posted December 30, 2012 Share Posted December 30, 2012 Wouldn't a big phased storm pull the cold air down with it? I guess it's possible but I don't like to depend on that. When that's the case the track is so important. If you're to close to the low then you're going to have temp issues. There can be big winners but serious losers also and I'm afraid we would lose...LOL. Personally would like to have a nice overrunning event with a nice high to the north. A classic SE snowstorm. Link to comment Share on other sites More sharing options...
Cold Rain Posted December 30, 2012 Author Share Posted December 30, 2012 The reason we're not seeing good arrangement and strength of high pressure and low pressure is the same reason we aren't seeing a big phase at a good location. A change in placement/trajectory/timing/strength of a couple of these critical pieces of energy can both produce a much stronger and colder system and help maintain, relocate, and strengthen high pressure. Of course, it could go the other way too. What you can't do is just automatically assume that if there is phasing and a perfect track, there will be no high pressure in a decent spot and of decent strength to transport in cold air. The same things that would help a phase will also play a crucial role in the development and evolution of high pressure. Link to comment Share on other sites More sharing options...
rduwx Posted December 30, 2012 Share Posted December 30, 2012 The reason we're not seeing good arrangement and strength of high pressure and low pressure is the same reason we aren't seeing a big phase at a good location. A change in placement/trajectory/timing/strength of a couple of these critical pieces of energy can both produce a much stronger and colder system and help maintain, relocate, and strengthen high pressure. Of course, it could go the other way too. What you can't do is just automatically assume that if there is phasing and a perfect track, there will be no high pressure in a decent spot and of decent strength to transport in cold air. The same things that would help a phase will also play a crucial role in the development and evolution of high pressure. I agree Cold Rain with a lot of what you said but I don't think people should automatically assume that a phased system would bring snow to there back yard. We are going to need a good high to the north. If others are depending on dynamic cooling for the cold air, I'm afraid they might be disappointed. Link to comment Share on other sites More sharing options...
Cold Rain Posted December 30, 2012 Author Share Posted December 30, 2012 I agree Cold Rain with a lot of what you said but I don't think people should automatically assume that a phased system would bring snow to there back yard. We are going to need a good high to the north. If others are depending on dynamic cooling for the cold air, I'm afraid they might be disappointed. Totally agree, and that is a very important point. Brandon and several of us others have mentioned the possibility of phasing. Sometimes we have a tendency to think that means we're going to get snow. If it phases in the right place, we probably will. But it could phase so that it runs up west of the Apps and we get rain. It could phase so that it runs through the Piedmont and gives the mountains/foothills snow and we get rain east of that. It could phase along the coast, bringing more snow to more folks. Or it could not phase at all...and this is probably the most likely scenario. From a dynamic cooling standpoint, if phasing takes place in the right place, there should be enough cold air drawn into the storm to support snow. Unlike other times when we would have to rely on dynamic cooling, we're often dealing with stale cold air and systems that aren't necessarily all that dynamic, producing low precip rates and whatever. In this case, if we get phasing, I would be less concerned about the dynamics of the storm doing their job to cool the column. The really important points with this system is that there really could be anything from a phased system to a big fat nothing, that even with phasing, there might not be a lot of snow for a lot of folks, that there is some good, fresh cold air that will be available to be tapped, and that dynamic cooling from a phased storm would probably be substantial enough to produce significant snow on the north and west sides of the system. Link to comment Share on other sites More sharing options...
NCSNOW Posted December 30, 2012 Share Posted December 30, 2012 'franklin NCwx' Like the Ukie? I wish weathernc was around. He posted some valuable info on models back in 2010 and one of the things pointed out was how well the Ukie verified on catching phased GOM storms compared to other models. Not saying this will be the case this time, but that always sticks in the back of mind. Link to comment Share on other sites More sharing options...
franklin NCwx Posted December 30, 2012 Share Posted December 30, 2012 'franklin NCwx' Like the Ukie? I wish weathernc was around. He posted some valuable info on models back in 2010 and one of the things pointed out was how well the Ukie verified on catching phased GOM storms compared to other models. Not saying this will be the case this time, but that always sticks in the back of mind. Yes, i remember that. NCEP had a write up on it. You can see how the northern stream is much farther west on the ukie compared to the other models. Check out the 12z cmc ensembles. Link to comment Share on other sites More sharing options...
SN_Lover Posted December 30, 2012 Share Posted December 30, 2012 'franklin NCwx' Like the Ukie? I wish weathernc was around. He posted some valuable info on models back in 2010 and one of the things pointed out was how well the Ukie verified on catching phased GOM storms compared to other models. Not saying this will be the case this time, but that always sticks in the back of mind. come to think of it the synoptic setup looks similar to 2010. just gotta get the phasing A little more than a week before the storm arrived, the extended range guidance from the GFSGFS and ECMWF guidance on 12/23 was in fairly good agreement with a storm track off the coast but close enough to bring some precipitation across central and eastern North Carolina. By day 2, with the 00 UTC 12/24 and 12 UTC 12/24 runs, the models were in good agreement in significantly shifting the storm system far enough offshore to bring little if any precipitation across central North Carolina. This was a significant shift eastward and which suggested a low to no impact event in central North Carolina. The 18 UTC runs on 12/24 and the 00 UTC and 12 UTC runs on 12/25 then shifted the storm track westward and showed significant deepening. This track would bring a significant winter storm to the Carolinas. This solution would eventually verify fairly well and was close to the ECMWF forecast 6 to 7 days out. The erratic nature of the NWP guidance with this event will like be a topic of research for several years to come. Researchers are suggesting that the large shift in the forecast track with the 00 UTC 12/24 and 12 UTC 12/24 runs may have originated from small initial condition uncertainties/errors in the short wave trough in the central and southern Plains. Small initial condition differences with the GFS and the ECMWF at 1200 UTC 12/24 appear to have amplified to large differences in the forecast 36-48 hours later. http://www4.ncsu.edu...cases/20101226/ Link to comment Share on other sites More sharing options...
ncskywarn Posted December 30, 2012 Share Posted December 30, 2012 NWS RALEIGH AFD .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 240 PM SUNDAY... AN ACTIVE SOUTHERN BRANCH OF THE JETSTREAM WITHIN THE SPLIT FLOW REGIME IN PLACE OVER THE CONUS WILL DOMINATE THE LONG TERM PERIOD. CONFIDENCE DURING THE LONG TERM PERIOD REMAIN BELOW AVERAGE DUE TO THE INDIVIDUAL MODELS AND THEIR RUN-TO-RUN VARIABILITY IN HANDLING THE SPLIT-FLOW PATTERN AND EMBEDDED ENERGY MOVING AROUND THE RIDGE THROUGH SOUTHWEST CANADA AND THE DESERT SOUTHWEST. JUST HOW MUCH UPSTREAM NORTHERN-SOUTHERN STREAM TROUGH INTERACTION WILL BE THE DRIVING FORCE AS TO WHEN/WHERE SFC CYCLOGENESIS WILL ENSUE OVER THE GULF COAST STATES AND SOUTHEAST US DURING THE THURSDAY-WEEKEND PERIOD. LATEST 12Z/30 MODEL GUIDANCE HAS TRENDED TOWARDS AN UNPHASED SOLUTION WITH A MORE DOMINATE NORTHERN STREAM INFLUENCE WHICH SUPPRESSES THE PRECIP FARTHER SOUTH AND EAST...KEEPING CENTRAL NC DRY WITH THE EXCEPTION OF COASTAL/EASTERN SECTIONS OF THE STATE. THIS COMPLEX AND DELICATE PATTERN WILL TAKE SOME TIME FOR MODELS TO RESOLVE...SO WILL CONTINUE WITH SLIGHT TO SMALL CHANCE POPS FOR THURSDAY THROUGH THE FRIDAY NIGHT PERIOD WITH BELOW NORMAL TEMPERATURES THROUGH THE PERIOD. Link to comment Share on other sites More sharing options...
burgertime Posted December 30, 2012 Share Posted December 30, 2012 Thing to look out for with future runs as Brandon said is if it slows down the northern energy. On the 18z it slows it down but not really enough. Even just the little change it had you see that there is a little more moisture in SC on this run. Link to comment Share on other sites More sharing options...
HKY_WX Posted December 30, 2012 Share Posted December 30, 2012 Thing to look out for with future runs as Brandon said is if it slows down the northern energy. On the 18z it slows it down but not really enough. Even just the little change it had you see that there is a little more moisture in SC on this run. It's really close to a phase. It's impossible to predict how any particular s/w will evolve b/c every storm is different. In effect we're talking about the evolution of wind currents, water vapor, etc. So all you can do is have some goal posts to look for. We have a large PNA ridge, we have a 50/50 low, and we have an active STJ. The models could be completely missing a small piece of mid-level vorticity, which would dramatically alter the downstream evolution. It wouldn't take much at all to trigger a cutoff phase over the southeast. W/ a kicker behind this system, it's not likely it could spin up too too much, but a snowstorm from VA to northern SC is still not out of the question at all. Of course it may not come together, as it usually doesn't, but when you have the right pattern, the odds increase. Which is why we are all interested. Link to comment Share on other sites More sharing options...
Pilotwx Posted December 30, 2012 Share Posted December 30, 2012 18z GFS looks close, really close. That low over the Baja is going to slow down some when it hits the SE ridge, the low is not strong enough to just plow right through the SE ridge. Link to comment Share on other sites More sharing options...
HKY_WX Posted December 30, 2012 Share Posted December 30, 2012 I think the most obvious region to look for model errors is going to be w/ the northern branch. The southern stream is generally modeled much better, timing wise, inside of 5 days. If this s/w over the Dakotas were to say, split into two different pieces w/ one piece heading towards the great lakes and another diving much further south, that would trigger a phase. The reason this area may be more likely to be modeled incorrectly is b/c the PNA ridge is going accelerate this s/w towards the south and I've noticed that sometimes causes model errors in s/w evolutions. Link to comment Share on other sites More sharing options...
Carvers Gap Posted December 30, 2012 Share Posted December 30, 2012 Check out Fairbanks' departures for December - unreal. That, according to the models, is about to change. That should at least give us a chance as Wow was alluding to. However, it has been my experience that when Alaska has extreme cold it is pretty much the opposite here in TN. So, getting that anomaly out of the way is at least a step. By no means is it a guarantee it gets colder...but like I said, it's a start. Addendum...The last two runs of the GFS bring cold back to Alaska @ 240 hrs like gangbusters. Link to comment Share on other sites More sharing options...
POWERSTROKE Posted December 30, 2012 Share Posted December 30, 2012 Gfs @240 has showed us cold for last four weeks. So doubt that will be trustworthy. However probably our luck Link to comment Share on other sites More sharing options...
Carvers Gap Posted December 30, 2012 Share Posted December 30, 2012 Gfs @240 has showed us cold for last four weeks. So doubt that will be trustworthy. However probably our luck Not really warm for us either as a matter of fact. The trough stretches from one end of the continent to the other. I remember seeing this on a few model runs in late November and being impressed. However, I always think it is fishy when both places are cold at once. It can happen, but not often. The wavelengths look longer to my novice eye this time. The cold just eventually presses south and overwhelms the pattern. Again, that sounds exactly like what I posted in late November so I am a little skeptical. The models have not been performing well past day 5...so take what ever they are spitting out w/ a grain of salt. Also, I am just looking at the operational runs and not the ensembles. Link to comment Share on other sites More sharing options...
POWERSTROKE Posted December 30, 2012 Share Posted December 30, 2012 Not really warm for us either as a matter of fact. The trough stretches from one end of the continent to the other. I remember seeing this on a few model runs in late November and being impressed. However, I always think it is fishy when both places are cold at once. It can happen, but not often. The wavelengths look longer to my novice eye this time. The cold just eventually presses south and overwhelms the pattern. Again, that sounds exactly like what I posted in late November so I am a little skeptical. The models have not been performing well past day 5...so take what ever they are spitting out w/ a grain of salt. Also, I am just looking at the operational runs and not the ensembles. I agree. Im just saying we havent been cold. Feels normal to me at least in my area. Link to comment Share on other sites More sharing options...
griteater Posted December 31, 2012 Share Posted December 31, 2012 'franklin NCwx' Like the Ukie? I wish weathernc was around. He posted some valuable info on models back in 2010 and one of the things pointed out was how well the Ukie verified on catching phased GOM storms compared to other models. Not saying this will be the case this time, but that always sticks in the back of mind. Here's the info regarding phasing with the UKMet... From HPC/NCEP - http://www.hpc.ncep.noaa.gov/mdlbias/biastext.shtml "Seems better than GFS with forecast of phasing of systems in northern and southern branch of jet...When GFS is showing phasing of systems beyond 84 hours, check UKMET to see if solution is consistent" From PSU EWall - http://www.personal.psu.edu/adb241/eWallTutorial/models/ukmet.htm "One benefit of the UKMet model is that it seems that the model does fairly well in forecasting the phasing of systems in the northern and southern branches of the jet stream across the northern hemisphere." Link to comment Share on other sites More sharing options...
HKY18 Posted December 31, 2012 Share Posted December 31, 2012 Like the Ukie? FWIW the ukmet was actually an apps runner with the phase at 12z, definitely interested to see what it has to say at 0z. Edit........ It actually is either much later with timing or it's a totally different system all together, because it has a 1003 LP in TN/KY at 144hrs which would be next saturday. Link to comment Share on other sites More sharing options...
metwannabe Posted December 31, 2012 Share Posted December 31, 2012 Here's the info regarding phasing with the UKMet... From HPC/NCEP - http://www.hpc.ncep..../biastext.shtml "Seems better than GFS with forecast of phasing of systems in northern and southern branch of jet...When GFS is showing phasing of systems beyond 84 hours, check UKMET to see if solution is consistent" From PSU EWall - http://www.personal....odels/ukmet.htm "One benefit of the UKMet model is that it seems that the model does fairly well in forecasting the phasing of systems in the northern and southern branches of the jet stream across the northern hemisphere." Thanks grit some informative reading to say the least but I did notice that the problem with how the GFS handles the phasing is this..... "Ambitious to phase northern and southern stream systems in fast and spit flow patterns beyond fhr 84" Considering the GFS has not shown any full phase yet I would think that doesn't bode very well for this particular system. Link to comment Share on other sites More sharing options...
burgertime Posted December 31, 2012 Share Posted December 31, 2012 Here is the Ukie... Link to comment Share on other sites More sharing options...
BIG FROSTY Posted December 31, 2012 Share Posted December 31, 2012 fwiw jb says finally a model sees his worry, whatever that means? can't believe nothing comes out of this trough!!! Link to comment Share on other sites More sharing options...
dsaur Posted December 31, 2012 Share Posted December 31, 2012 Well, Larry was saying the models had a cold bias, and Dec. wasn't going to be so good, and here it is one day left, and Dec ain't been so good. I guess those that pounded him on it, are wondering where the cold is, lol. I'm at 32 right now, but don't expect 15 by morning. Not saying it won't turn bitter before the big baby drop, but I'm not holding my breath! Guess the models can't figure in that pig ridge too well. Too bad because my "guess the first storm" choice was Jan 3rd. and it's closing on me like a freight train, lol. T Link to comment Share on other sites More sharing options...
SN_Lover Posted December 31, 2012 Share Posted December 31, 2012 fwiw jb says finally a model sees his worry, whatever that means? can't believe nothing comes out of this trough!!! From snow to rain to thunderstorms? what a crazy spread in the models. Link to comment Share on other sites More sharing options...
NCStateMMY Posted December 31, 2012 Share Posted December 31, 2012 From snow to rain to thunderstorms? what a crazy spread in the models. That is a severe weather look there. Link to comment Share on other sites More sharing options...
burgertime Posted December 31, 2012 Share Posted December 31, 2012 NAM is very close to a big phase...but alas it's the LR NAM. Link to comment Share on other sites More sharing options...
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