Cold Rain Posted January 23, 2011 Share Posted January 23, 2011 There seems to be a variety of perspectives on (and frequent misapplication of) model trends and seasonal trends of late. Model Trends: Some have referred to a model trending warmer or colder or westward or eastward than it's previous run (I've been guilty of that too). While that technically may be true, it offers little value to forecasting, other than to correctly say that there is greater uncertainty in the situation. For this type of observation to be useful in trying to ascertain the details of a complex situation, you should observe both the trend of the elements in the model against itself over several run cycles and/or the trend in elements of the model against the trends of the same elements in other models. For example: "The 0Z Ukie shifts east compared to it's 12Z run" tells you very little, unless other models are and/or have been doing the same. But, if it shifts east again on the next 0Z run, then you have a potentially useful trend. In the case of our storm, it went west. So it was west, went east, and went west again. Another good example is the high pressure in the northeast. Originally, most models were very slow in moving that feature out to sea. Over several run cycles, they moved it out with more haste. That's an example of a useful trend in which there was good consensus. Seasonal Trends: There are plenty of examples of comments like, "Things have trended east all season, so I'm not buying a westward track." Or, "High pressure has stayed locked in place longer than the models have shown all season, so I think it's gonna hang on longer this time too." That is a faulty conclusion and will most likely lead one down a road of misery and disappointment. Playing the seasonal trend card without analyzing and comparing the current pattern to the seasonal pattern to date is a mistake. For example: The seasonal trend so far has been for storms to not really cut inland too much. Also, it has seemed that confluence has remained in the NE a bit longer than the models suggested, thus far. Therefore, it might be easy to apply those things to the current situation. But by examining the pattern and realizing that up until just recently, we've had major blocking, an element missing in our current pattern, the application of the seasonal trend to those components is in error. Blocking suppresses and slows the pattern. High pressure can remain favorably located longer and storms can better avoid cutting too far inland. The bottom line is, look at the pattern we're in before employing a seasonal trend which might have been specific to a different pattern. And make sure to examine a model elements against several runs of itself and other models before declaring a trend. Doing otherwise will likely lead to erroneous conclusions. Link to comment Share on other sites More sharing options...
lilj4425 Posted January 23, 2011 Share Posted January 23, 2011 this place was loaded last night... no huge changes in euro and gfs... and the NAM shows rain and everyone gets off? It's not just the NAM. Link to comment Share on other sites More sharing options...
jburns Posted January 23, 2011 Share Posted January 23, 2011 this place was loaded last night... no huge changes in euro and gfs... and the NAM shows rain and everyone gets off? Yeah that's it. Only the NAM shows rain. Of course I don't know where you are. Maybe you are on top of Mt. Mitchell. Link to comment Share on other sites More sharing options...
snow for dylan Posted January 23, 2011 Share Posted January 23, 2011 and some other unrealiable models.... if i can down to it it would be euro and gfs in the end. Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2011 Share Posted January 23, 2011 Looks like the GFS may be going the way of the NAM tonight. Link to comment Share on other sites More sharing options...
bingcrosbyb Posted January 23, 2011 Share Posted January 23, 2011 Ruh roh. GFS looking NAM-ish through 48HR. Link to comment Share on other sites More sharing options...
HKY18 Posted January 23, 2011 Share Posted January 23, 2011 oh yeah much more digging this run its gonna be different than 12z for sure.we'll see Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2011 Share Posted January 23, 2011 @60 our LP is over southern LA...these next frames will tell the tale. Link to comment Share on other sites More sharing options...
Marion_NC_WX Posted January 23, 2011 Author Share Posted January 23, 2011 Looks like the GFS may be going the way of the NAM tonight. It's definitely looking that way early on...1009 mb surface low just off the Louisiana Coast at 60 hours... EDIT: one difference I do see in the GFS (vs NAM) is no weak low in Southern Canada and somewhat better freezing line out ahead of the system. Link to comment Share on other sites More sharing options...
HKY18 Posted January 23, 2011 Share Posted January 23, 2011 the northern stream s/w is not digging as much as 12z. at hr 60 Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2011 Share Posted January 23, 2011 @69 that LP is heading due east one LP is just to the south of it kind of like the NAM....temps still too warm for everyone west of the apps....@72 that second LP is heading across the FL pan handle and heavy moisture is moving into GA Link to comment Share on other sites More sharing options...
rduwx Posted January 23, 2011 Share Posted January 23, 2011 Looks like neg tilt at hr 72...I would think this is going inland. I don't really care, I want my 2" of rain. Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2011 Share Posted January 23, 2011 @78 our low is bombing right over SAV. Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2011 Share Posted January 23, 2011 Those lows are making a 7 - 10 split with NC in the middle. Link to comment Share on other sites More sharing options...
Marion_NC_WX Posted January 23, 2011 Author Share Posted January 23, 2011 @78 our low is bombing right over SAV. You sure? Maybe I'm reading it wrong but on Allan's site, there's a 1001 mb low getting ready to enter Southwest Georgia... Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2011 Share Posted January 23, 2011 Looks like SW NC wins big this run, that second low slams into them and really brings the temps down it. Link to comment Share on other sites More sharing options...
bingcrosbyb Posted January 23, 2011 Share Posted January 23, 2011 GFS is bombing in the gulf Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2011 Share Posted January 23, 2011 You sure? Maybe I'm reading it wrong but on Allan's site, there's a 1001 mb low getting ready to enter Southwest Georgia... There are two lows...unless I'm reading something wrong this run. Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2011 Share Posted January 23, 2011 Interesting run, our 850's drop fast near the end but it might be too late outside of a flurry or two. Link to comment Share on other sites More sharing options...
weatherfide Posted January 23, 2011 Share Posted January 23, 2011 Wow. There is no cold air in this for anyone on the GFS. Link to comment Share on other sites More sharing options...
Marion_NC_WX Posted January 23, 2011 Author Share Posted January 23, 2011 999mb low over Augusta at 84 hours, but the 850's are trying to wedge into Northwestern North Carolina...interesting. Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2011 Share Posted January 23, 2011 Wow. There is no cold air in this for anyone on the GFS. Plenty of cold air for the mountains of NC. Link to comment Share on other sites More sharing options...
bingcrosbyb Posted January 23, 2011 Share Posted January 23, 2011 H5 closed off over AL @ 78. :popcorn:First time I've seen that. http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/00/images/gfs_500_078l.gif Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2011 Share Posted January 23, 2011 And the MA wins. Link to comment Share on other sites More sharing options...
weatherfide Posted January 23, 2011 Share Posted January 23, 2011 Plenty of cold air for the mountains of NC. Yeah, I should've said outside of the mountains. It's just much warmer than the 18z is what I meant. Link to comment Share on other sites More sharing options...
lilj4425 Posted January 23, 2011 Share Posted January 23, 2011 And the MA wins. That's the worst news of all. Link to comment Share on other sites More sharing options...
bingcrosbyb Posted January 23, 2011 Share Posted January 23, 2011 2-4" snow for N MS http://www.twisterdata.com/data/models/gfs/3/maps/2011/01/23/00/GFS_3_2011012300_F78_SNOWIN_SURFACE.png Link to comment Share on other sites More sharing options...
Pilotwx Posted January 23, 2011 Share Posted January 23, 2011 This thing bombs out big time! @ 90hr. GFS All so a repost of yesterdays play by play for the storm. FROM FRIDAY <li style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; ">Okay, I giving a play by play from now till the storm 1.) Tonight the Euro takes our hope away for the storm! 2.) Tomorrow the GFS, NAM take way our storm. GFS( took it away one run earlier) 3.) Sunday GFS starts to trend back to a storm but not so big, with the NAM to follow. 4.) Early in the wee morning hours of Monday the EURO, GFS are hinting this thing is going to be a major hit. 5.) Monday evening we start to get some people putting out amounts and lots are Happy and Few no so much. 6.) Tuesday it starts snowing and those who are getting snow are as happy as a cheshire cat. 7.) Wed. we add up the snow totals and find the winners and losers. At the same time we are already on the look out for then next storm. 8.) WED., Thurs those who got a foot plus of snow want more and those who got nothing want more!<li> Link to comment Share on other sites More sharing options...
HKY18 Posted January 23, 2011 Share Posted January 23, 2011 it looks to me basing this only on the 850 line that around hky and morganton into the mountains it switches over to about .50-.75 of snow after about .50-.75 of rain so but with there being so a warm nose it may be rain or sleet pretty strong 850 low as well. Link to comment Share on other sites More sharing options...
Marion_NC_WX Posted January 23, 2011 Author Share Posted January 23, 2011 This model run is trying it dang-est to produce a big time snow for the Mountains and maybe Foothills (West of HWY 321)... at hour 84 even with the surface low placement not the best, you got the best lift coming into Western North Carolina, a 500mb and 850mb track just under the mountains and the freezing line trying to wedge along the escarpment. All of the dynamics in play will be occuring during the overnight hours Tuesday into Wednesday. If we're gonna get somebody a snowstorm out of this, it will have to be with the dynamics at the perfect time of the day. Link to comment Share on other sites More sharing options...
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