vinylfreak89 Posted March 2, 2013 Share Posted March 2, 2013 I would argue (and would want some of dtk's opinions) that the small details here such as splitting off from the northern stream, some southern stream interaction, and possibly phasing with the northern stream again late is likely adding much more to model difficulties than lack of UA sampling of the upper low. Also, as in most cases, ejecting lows interacting with the complex terrain of the Rockies adds additional variability. It is a tricky UA pattern for the models to handle. this and the complex evolution of the pseudo 50/50 feature (which I think honestly has had at least 60 % of the impact) Link to comment Share on other sites More sharing options...
yoda Posted March 2, 2013 Share Posted March 2, 2013 Looks like the base of the trough should be fully inland by 06z, so 12z for good raob coverage. Though, I suspect it is close enough to shore (and therefore the airports) that we are getting decent flight-based coverage already. Thanks for that Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted March 2, 2013 Share Posted March 2, 2013 new kensington PA and not a met and never seen you post here before,..dont let the door hit your interloping ass on the way out You make my sides hurt. On a more serious note, is anyone encouraged by the lining up of the GFS, GGEM, NAM, srefs? I like the agreement. Link to comment Share on other sites More sharing options...
yoda Posted March 2, 2013 Share Posted March 2, 2013 Ironically, 18z GFS total QPF is close to the total QPF of the 18z DGEX Link to comment Share on other sites More sharing options...
dtk Posted March 2, 2013 Share Posted March 2, 2013 I would argue (and would want some of dtk's opinions) that the small details here such as splitting off from the northern stream, some southern stream interaction, and possibly phasing with the northern stream again late is likely adding much more to model difficulties than lack of UA sampling of the upper low. Also, as in most cases, ejecting lows interacting with the complex terrain of the Rockies adds additional variability. It is a tricky UA pattern for the models to handle. All fair points....it's not like this is a straightforward forecast and a done deal despite the growing consensus. Just look at how much the solution has evolved over the past 36 hours (despite the similar end result). Link to comment Share on other sites More sharing options...
Deck Pic Posted March 2, 2013 Share Posted March 2, 2013 DCA has a chance to log a "March" date into the chart below. Maybe 5% to 10% probability? It would have to shove one of the other dates aside. sno.png those arent actually snowstorm totals so 1996 is slightly too high and 2003 is slightly too low Link to comment Share on other sites More sharing options...
Deck Pic Posted March 2, 2013 Share Posted March 2, 2013 I'dlike DCA to get enough tmake your winter forecast look good in terms of snow. I have my doubts that dca would get that much with marginal temps. On grass I would probably do better than them despite being east but I suspect I'd still get screwed. I would like someone in the area to get 1958 type snow. That would be a success. But this is probably a best case scenario. Any more northward shift and we might pay in terms of temps. I think DCA would need 6-8" for me to say that my outlook was pretty good on snow...unless of course we get another snowstorm after this Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted March 2, 2013 Share Posted March 2, 2013 Ironically, 18z GFS total QPF is close to the total QPF of the 18z DGEX And GGEM. Link to comment Share on other sites More sharing options...
gymengineer Posted March 2, 2013 Share Posted March 2, 2013 those arent actually snowstorm totals so 1996 is slightly too high and 2003 is slightly too low It was a bad decision for them to toss aside the snowstorms lists and go to this 1-day, 2-day, 3-day ranking. I know why they did it in terms of climate records, but lumping the clipper snow with the 1/96 blizzard makes no sense. Link to comment Share on other sites More sharing options...
Deck Pic Posted March 2, 2013 Share Posted March 2, 2013 It was a bad decision for them to toss aside the snowstorms lists and go to this 1-day, 2-day, 3-day ranking. I know why they did it in terms of climate records, but lumping the clipper snow with the 1/96 blizzard makes no sense. it is also deceptive in terms of dates since we all know the snow started saturday night....the beltway was covered by 10pm Link to comment Share on other sites More sharing options...
vinylfreak89 Posted March 2, 2013 Share Posted March 2, 2013 Looks like overall, there is good model consistency again between most of the 12Z non US and the 18Z US suites. Link to comment Share on other sites More sharing options...
gymengineer Posted March 2, 2013 Share Posted March 2, 2013 it is also deceptive in terms of dates since we all know the snow started saturday night....the beltway was covered by 10pm Yup, and if they are going to do it this way, then shouldn't there be two entries for 1/96? 1/6-8 and 1/7-9? Link to comment Share on other sites More sharing options...
dtk Posted March 2, 2013 Share Posted March 2, 2013 i think it is shortsighted to talk about verification scores and what data is ingested in the model and how by definition it should perform better than 12z in the means since it is 6 hours later....when we all have anecdotal evidence and experience that it is not as skilled in our backyard and often has goofy solutions that are an outlier....In fact there is a certain renowned met who posts in our forum, who has a less than glowing opinion of the off GFS runs, especially 18z, but I will let him speak for himself on that if he wants to That's fine, but your evidence is purely anecdotal. In fact, there used to be a considerable gap between 06/18 and the 00/12 cycles, but as the models, assimilation, and observations have improved, this gap has been narrowed consideribly (and in the 4-5 day lead time, basically closed within any statistical significance). This does not guarantee that this will be the case for any individual discrete, regional event. I don't really need a lesson on error growth nor data assimilation cycling. I'd be happy to discuss this in more detail with any renowned met (and if it is who i think you are referring to, will be sure to do so over a beer the next time we are out golfing). Link to comment Share on other sites More sharing options...
Deck Pic Posted March 2, 2013 Share Posted March 2, 2013 upper NW at 90 hours Link to comment Share on other sites More sharing options...
Deck Pic Posted March 2, 2013 Share Posted March 2, 2013 That's fine, but your evidence is purely anecdotal. In fact, there used to be a considerable gap between 06/18 and the 00/12 cycles, but as the models, assimilation, and observations have improved, this gap has been narrowed consideribly (and in the 4-5 day lead time, basically closed within any statistical significance). This does not guarantee that this will be the case for any individual discrete, regional event. I don't really need a lesson on error growth nor data assimilation cycling. I'd be happy to discuss this in more detail with any renowned met (and if it is who i think you are referring to, will be sure to do so over a beer the next time we are out golfing). I do appreciate the info....since there is some conventional wisdom that the 18z runs are not as skilled...I will defer to you on this one...maybe these are old biases that no longer have any credence even in our backyard Link to comment Share on other sites More sharing options...
Fodie77 Posted March 2, 2013 Share Posted March 2, 2013 Looks to be yet another Richmond screwjob Congrats if it verifies... Link to comment Share on other sites More sharing options...
swimmatte Posted March 2, 2013 Share Posted March 2, 2013 upper NW at 90 hours I suck at reading soundings, but by the looks of it from looking at some other info it seems 18z GFS was pretty much all rain for DCA. I hope I'm wrong. Link to comment Share on other sites More sharing options...
RitualOfTheTrout Posted March 2, 2013 Share Posted March 2, 2013 new kensington PA and not a met and never seen you post here before,..dont let the door hit your interloping ass on the way out Sorry, I meant no disrespect. Just poking fun at how weenies in ALL regions spin the off hour runs to prop up the hope for snow. Very infrequent poster in the mid atlantic forum, but lurk pretty regularly. Link to comment Share on other sites More sharing options...
Ian Posted March 2, 2013 Share Posted March 2, 2013 I do appreciate the info....since there is some conventional wisdom that the 18z runs are not as skilled...I will defer to you on this one...maybe these are old biases that no longer have any credence even in our backyard I've wondered about the global/NH type scores .. at least how useful they are to the everyday happenings in any one location like our backyards. I don't understand it all enough though to be honest.. I wish laymen wouldn't talk about it as if it's always meaningful because I don't think they understand it either. But in the end I bet a good part of it is the same stuff that makes us think there is a DC split, a Norman hole, etc. Link to comment Share on other sites More sharing options...
Deck Pic Posted March 2, 2013 Share Posted March 2, 2013 I suck at reading soundings, but by the looks of it from looking at some other info it seems 18z GFS was pretty much all rain for DCA. I hope I'm wrong. this is probably heavy wet snow....not sure how warm the boundary layer can get at DCA....it might be useful to look at soundings from other paste jobs...2/22/87.....March 29, 1942 is probably a good analog....as it fell in such a short amount of time.... 11/11/87? Link to comment Share on other sites More sharing options...
Deck Pic Posted March 2, 2013 Share Posted March 2, 2013 Sorry, I meant no disrespect. Just poking fun at how weenies in ALL regions spin the off hour runs to prop up the hope for snow. Very infrequent poster in the mid atlantic forum, but lurk pretty regularly. Link to comment Share on other sites More sharing options...
stormtracker Posted March 2, 2013 Author Share Posted March 2, 2013 I suck at reading soundings, but by the looks of it from looking at some other info it seems 18z GFS was pretty much all rain for DCA. I hope I'm wrong. huh???? Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted March 2, 2013 Share Posted March 2, 2013 I suck at reading soundings, but by the looks of it from looking at some other info it seems 18z GFS was pretty much all rain for DCA. I hope I'm wrong. I suck at reading them too, but that seems like snow to me. Link to comment Share on other sites More sharing options...
winterymix Posted March 2, 2013 Share Posted March 2, 2013 I suck at reading soundings, but by the looks of it from looking at some other info it seems 18z GFS was pretty much all rain for DCA. I hope I'm wrong. The column is saturated up to 450 level which may imply good dendritic growth layer. The snow may partially melt near the ground but if it comes down fast, will drag down enough cold air to get the boundary layer to 32 - 34 degrees quickly. Link to comment Share on other sites More sharing options...
Heisy Posted March 2, 2013 Share Posted March 2, 2013 Remember on soundings skew-t chart the temperature lines run on an angle not vertical. Probably why people see them and think rain all the time lol. Link to comment Share on other sites More sharing options...
Terpeast Posted March 2, 2013 Share Posted March 2, 2013 I suck at reading soundings, but by the looks of it from looking at some other info it seems 18z GFS was pretty much all rain for DCA. I hope I'm wrong. Definitely a snow sounding. Wet snow. Link to comment Share on other sites More sharing options...
Deck Pic Posted March 2, 2013 Share Posted March 2, 2013 I've wondered about the global/NH type scores .. at least how useful they are to the everyday happenings in any one location like our backyards. I don't understand it all enough though to be honest.. I wish laymen wouldn't talk about it as if it's always meaningful because I don't think they understand it either. But in the end I bet a good part of it is the same stuff that makes us think there is a DC split, a Norman hole, etc. i am not attributing this to DTK, but there are a lot of math minds who don't believe in intangibles....like heaters in poker or blackjack or even horse racing...that there is no such thing as running good or running bad.....intangibles are very very real....I am not convinced that 18z is as good a run in our backyard and we all know the DC split exists.... Link to comment Share on other sites More sharing options...
dtk Posted March 2, 2013 Share Posted March 2, 2013 I do appreciate the info....since there is some conventional wisdom that the 18z runs are not as skilled...I will defer to you on this one...maybe these are old biases that no longer have any credence even in our backyard That's why I have to provide that caveat that it doesn't hold for every event, especially when you break it down into something specific/regional. I think that the 00/12 UTC cycles are more prone to big shifts for forecasts in our back yard, because of the assimilation of high quality, high-vertical density raob data. By the way, goofy things do tend to happen with various runs of the regional systems, in particular the NAM I think, because they use partial cycling (i.e. they back up 12 hours, I think twice a day, and reset to the global model and spin back up to real-time). I suspect this leads to huge discontinuities (in terms of dprog/dt) for the 06/18 NAM runs ....at least that is my hypothesis. Link to comment Share on other sites More sharing options...
EasternUSWX Posted March 2, 2013 Share Posted March 2, 2013 Yes please. North again. Link to comment Share on other sites More sharing options...
Deck Pic Posted March 2, 2013 Share Posted March 2, 2013 Remember on soundings skew-t chart the temperature lines run on an angle not vertical. Probably why people see them and think rain all the time lol. everyone in this forum knows at least the basics of how to read a skew-t....this isnt the Philly or NYC forum Link to comment Share on other sites More sharing options...
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