burgertime Posted February 15, 2012 Share Posted February 15, 2012 Wow the NAM is blowing up our storm in TX...lots of QPF with this. Also pulling in some cold air on the backside. This run is not as cold for our area as the 6z NAM or the 00z NAM so that kind of sucks. Out to 78. Link to comment Share on other sites More sharing options...
burgertime Posted February 15, 2012 Share Posted February 15, 2012 The NAM at hour 84 says congrats Dallas TX. Hard to tell exactly where the LP is @84 but appears to be on the southern side of LA. Link to comment Share on other sites More sharing options...
WeatherNC Posted February 15, 2012 Share Posted February 15, 2012 Differences between the NAM & GFS are comical, NAM with a 550'ish bowling ball rolling through southern TX, GFS open wave, not even close. Both picking up on some energy in NE / IA that needs to be watched, but through 72hrs, no evidence of being sheared out like the global, compact H5 low, abs vort in the >40 s^-1 range. Link to comment Share on other sites More sharing options...
bingcrosbyb Posted February 15, 2012 Share Posted February 15, 2012 12z NAM has a very strong vort in TX with energy diving from the north. TX getting absolutely crushed. Congrats Dallas on your foot of snow. Link to comment Share on other sites More sharing options...
burgertime Posted February 15, 2012 Share Posted February 15, 2012 12z NAM has a very strong vort in TX with energy diving from the north. TX getting absolutely crushed. Congrats Dallas on your foot of snow. Check out the cold air being pulled into the heart of TX...WOW. Link to comment Share on other sites More sharing options...
beanskip Posted February 15, 2012 Share Posted February 15, 2012 Question for mets: What if the s/w holds together and remains closed all the way through to the Atlantic? The 12z NAM shows a gorgeous 850 low over East Texas, presumably getting ready to march east across the south -- obviously big cutoffs come with their own built-in cold air mechanism as is seen over Texas on this run -- could this tranlsate further east??? Link to comment Share on other sites More sharing options...
burgertime Posted February 15, 2012 Share Posted February 15, 2012 Question for mets: What if the s/w holds together and remains closed all the way through to the Atlantic? The 12z NAM shows a gorgeous 850 low over East Texas, presumably getting ready to march east across the south -- obviously big cutoffs come with their own built-in cold air mechanism as is seen over Texas on this run -- could this tranlsate further east??? Robert seemed to love the idea of that last night via facebook...said that idea reminded him of 2004. Link to comment Share on other sites More sharing options...
packfan98 Posted February 15, 2012 Share Posted February 15, 2012 Doesn't the NAM have a tendency to over-amp energy and precip amounts? Maybe we should split the differences between the strength on the NAM and GFS and extrapolate from there. Looks as if the NAM is hinting at some positives early on in regards to the initial system and cold air. We are still waiting for all of the players to get on the field. Let's see where this goes in future runs. Link to comment Share on other sites More sharing options...
beanskip Posted February 15, 2012 Share Posted February 15, 2012 While the NAM looks more favorable than the GFS to be sure, I just compared the 12 NAM to the 6z NAM and it trended much warmer and also trended faster (and bit more south) with the southern stream system. Link to comment Share on other sites More sharing options...
bingcrosbyb Posted February 15, 2012 Share Posted February 15, 2012 I know extrapolating the NAM is fool's gold, but where would this track do you suppose? Inland west of the Apps? Tough to tell where the SLP will march from 84HR. Link to comment Share on other sites More sharing options...
burgertime Posted February 15, 2012 Share Posted February 15, 2012 Doesn't the NAM have a tendency to over-amp energy and precip amounts? Maybe we should split the differences between the strength on the NAM and GFS and extrapolate from there. Looks as if the NAM is hinting at some positives early on in regards to the initial system and cold air. We are still waiting for all of the players to get on the field. Let's see where this goes in future runs. That is usually correct. Once it gets into 48 hours it seems to pull back on qpf totals in a big way...or at least from what I can recall anyways. Link to comment Share on other sites More sharing options...
burgertime Posted February 15, 2012 Share Posted February 15, 2012 I know extrapolating the NAM is fool's gold, but where would this track do you suppose? Inland west of the Apps? Tough to tell where the SLP will march from 84HR. That was my worry looking at the NAM...it appeared to be close to taking the DGEX track....but if that ULL could stay in place and march east that might change the game so to speak. Link to comment Share on other sites More sharing options...
RaleighWx Posted February 15, 2012 Share Posted February 15, 2012 SOme things to note from the NAM. 1. The NAM is closest to the Canadian through 72-84 hours when compared with the GFS/ECMWF. 2. It is slower and more amplified with the southern stream system. At 84 hours it has a 1003mb low over SW Louisiana. The 6z GFS at 90 hours had it over south-central GEorgia, the 00z ECMWF at 96 hours had it near Mobile Bay, the 00z GGEM at 96 hours had it slightly further east than the NAM just south of the LA central coast. From the 6z GFS ENsemble members, it looked most like members p002, p005, p008, and p 010. http://raleighwx.americanwx.com/models/gfsensemble/members/06zf090.html 3. Also the NAM is much quicker with the northern stream cold front when compared with the GFS and ECMWF at the same time. The front is passing through central Virginia at 00z Sunday and pushing southeast. The area of low pressure will likely ride this front so to speak. If you extract out the 6z GFS Ensemble members and look at the Canadian, one would expect the 12z NAM would likely end up threatening at least, KY/TN/VA/northern NC with snow. It will be interesting to see if the 12z models trend slower/stronger with the southern stream system, and quicker with the cold front moving into the NOrtheast this saturday. Link to comment Share on other sites More sharing options...
WeatherNC Posted February 15, 2012 Share Posted February 15, 2012 Doesn't the NAM have a tendency to over-amp energy and precip amounts? Maybe we should split the differences between the strength on the NAM and GFS and extrapolate from there. Looks as if the NAM is hinting at some positives early on in regards to the initial system and cold air. We are still waiting for all of the players to get on the field. Let's see where this goes in future runs. I would probably go with the mesoscale model at this range given such an energized cutoff, higher res is likely giving a more accurate picture of how it will evolve moving eastward. SREF ens from 3z, ARW and NMM suite support this being closed off at-least through central TX, 12z NAM would imply maybe into LA. Link to comment Share on other sites More sharing options...
WhiteoutWX Posted February 15, 2012 Share Posted February 15, 2012 That high pressure looks like its trying to build southward from the midwest ahead of the low on the NAM. It is completely absent on the GFS, and is further north on the CMC/Euro. Link to comment Share on other sites More sharing options...
burgertime Posted February 15, 2012 Share Posted February 15, 2012 From the MA thread: 16 WSR dropsondes into the 12Z GFS...they were targeting the energy that will be part of the northern stream contribution to this system. I think we'll task them again tonight at 00Z and tomorrow at 12Z...after that all the players will be over the CONUS. Link to comment Share on other sites More sharing options...
burgertime Posted February 15, 2012 Share Posted February 15, 2012 SOme things to note from the NAM. 1. The NAM is closest to the Canadian through 72-84 hours when compared with the GFS/ECMWF. 2. It is slower and more amplified with the southern stream system. At 84 hours it has a 1003mb low over SW Louisiana. The 6z GFS at 90 hours had it over south-central GEorgia, the 00z ECMWF at 96 hours had it near Mobile Bay, the 00z GGEM at 96 hours had it slightly further east than the NAM just south of the LA central coast. From the 6z GFS ENsemble members, it looked most like members p002, p005, p008, and p 010. http://raleighwx.ame...rs/06zf090.html 3. Also the NAM is much quicker with the northern stream cold front when compared with the GFS and ECMWF at the same time. The front is passing through central Virginia at 00z Sunday and pushing southeast. The area of low pressure will likely ride this front so to speak. If you extract out the 6z GFS Ensemble members and look at the Canadian, one would expect the 12z NAM would likely end up threatening at least, KY/TN/VA/northern NC with snow. It will be interesting to see if the 12z models trend slower/stronger with the southern stream system, and quicker with the cold front moving into the NOrtheast this saturday. Thanks for this, bring us back down to earth. Link to comment Share on other sites More sharing options...
griteater Posted February 15, 2012 Share Posted February 15, 2012 I think the NAM has the better idea on keeping the stronger closed low coming into S Texas. However, it finally caved to the other models with respect to the vort dropping into Wyoming and Colorado at 54-60 - it hasn't shown this feature until this run....so by 84, the flow over the SE is more WSW instead of WNW. To me, the NAM would favor portions of AR/TN/NC Mtns/VA, but still a struggle to get enough cold air in east the mtns in NC. Awesome looking setup for moisture for whoever's cold enough. Link to comment Share on other sites More sharing options...
jmundie Posted February 15, 2012 Share Posted February 15, 2012 Those of us in middle and west tennessee are liking the look of the nam. I don't think it will be an apps runner. There is a 50/50 low. If I had to guess, the track from there for the surface low would be nola, to montgomery to charleston, maybe a turn up the coast for a bit, but out to sea. I don't think it can run up the coast with the low pressure in place in new england. Link to comment Share on other sites More sharing options...
GaWx Posted February 15, 2012 Share Posted February 15, 2012 Goofy is generally far better than the vietNAM at 84 hours. I would almost always lean toward Goofy. Think about this: the DGEX is the vietNAM extension. How often does the DGEX verify? Case closed. Link to comment Share on other sites More sharing options...
beanskip Posted February 15, 2012 Share Posted February 15, 2012 How often do any of them verify? Goofy is generally far better than the vietNAM at 84 hours. I would almost always lean toward Goofy. Think about this: the DGEX is the vietNAM extension. How often does the DGEX verify? Case closed. Link to comment Share on other sites More sharing options...
GaWx Posted February 15, 2012 Share Posted February 15, 2012 How often do any of them verify? Goofy at 90 hours isn't that bad and is generally a lot better than the atrocious DGEX. Link to comment Share on other sites More sharing options...
jmundie Posted February 15, 2012 Share Posted February 15, 2012 Goofy is generally far better than the vietNAM at 84 hours. I would almost always lean toward Goofy. Think about this: the DGEX is the vietNAM extension. How often does the DGEX verify? Case closed. I thought the DGEX runs on GFS software, from whatever the NAM is showing at 84? Its not like they use the same software for the NAM. So maybe the reason that DGEX is terrible is because its running GFS algos? It comes to drastically different solutions most of the time because the NAM and GFS at 84 are often strikingly different. Link to comment Share on other sites More sharing options...
WeatherNC Posted February 15, 2012 Share Posted February 15, 2012 Despite that cold pool aloft, not even close for Dallas this run at 84, last 1500' are in the 3-5C range... Link to comment Share on other sites More sharing options...
BrierCreekWx Posted February 15, 2012 Share Posted February 15, 2012 Goofy is generally far better than the vietNAM at 84 hours. I would almost always lean toward Goofy. Think about this: the DGEX is the vietNAM extension. How often does the DGEX verify? Case closed. I'm not sure that is a correct conclusion to come to. The DGEX - Downscaled GFS with Eta Extension - uses the previous run of the GFS for lateral boundary conditions - so it's got a lot of GFS influence in it if you think about it. http://www.emc.ncep.noaa.gov/mmb/mmbpll/dgexhome.ops/ Link to comment Share on other sites More sharing options...
jmundie Posted February 15, 2012 Share Posted February 15, 2012 I'm not sure that is a correct conclusion to come to. The DGEX - Downscaled GFS with Eta Extension - uses the previous run of the GFS for lateral boundary conditions - so it's got a lot of GFS influence in it if you think about it. http://www.emc.ncep....l/dgexhome.ops/ Yup - it actually runs the gfs results from hour 78 or so with the nam model resolution. So it means that the GFS sucks at 78 hours maybe "Summary: “DGEX” is an acronym for the Downscaled GFS with Eta Extension. DGEX has been developed as an interim solution to providing high-resolution – horizontally and vertically – forecast guidance for populating the digital forecast database at extended forecast projections. It is produced by running the full 12-km, 60 level, Eta model from forecast hour 78 to forecast hour 192 using lateral boundary conditions (LBC) from the previous cycle of the GFS. These LBC’s are applied at every 3 hours between 78 and 174 hr, and every 6 hours between 174 and 192 hrs. Although the process is started at 78 hrs to allow adjustment to the smaller grid, the first time step disseminated to the field is 90 hrs. DGEX is available on AWIPS beginning with OB3.3 " Link to comment Share on other sites More sharing options...
tarheelwx Posted February 15, 2012 Share Posted February 15, 2012 Despite that cold pool aloft, not even close for Dallas this run at 84, last 1500' are in the 3-5C range... Not surprised as I didn't see much cold air in TX. As for the SE, our only hope would be for the low to stay further south, strengthen to pull in cold air, and then maybe turn up the coast a bit. Looking at the last 3 panels from the 12z NAM, the lp has a strong northerly component........ not good for NC, SC, GA or even much of the mid atlantic as well. Maybe it will head due east. TW Link to comment Share on other sites More sharing options...
WhiteoutWX Posted February 15, 2012 Share Posted February 15, 2012 Despite that cold pool aloft, not even close for Dallas this run at 84, last 1500' are in the 3-5C range... The lack of cold air at the surface with this system seems to be a common theme on every model. Link to comment Share on other sites More sharing options...
GaWx Posted February 15, 2012 Share Posted February 15, 2012 I thought the DGEX runs on GFS software, from whatever the NAM is showing at 84? Its not like they use the same software for the NAM. So maybe the reason that DGEX is terrible is because its running GFS algos? It comes to drastically different solutions most of the time because the NAM and GFS at 84 are often strikingly different. It often comes to drastically different solutions because the 78 hour NAM is so often in lala land compared to the GFS. The DGEX, even very early in its run, is often so bad because of the garbage just fed into it by the 78 hour NAM as opposed to the then just introduced GFS influence. Link to comment Share on other sites More sharing options...
burgertime Posted February 15, 2012 Share Posted February 15, 2012 Despite that cold pool aloft, not even close for Dallas this run at 84, last 1500' are in the 3-5C range... I didn't necessarily expect to it be snow but just love seeing those 850 temps pulled down into it shows what can happen when you get the right storm. Link to comment Share on other sites More sharing options...
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