Fozz Posted February 14, 2012 Share Posted February 14, 2012 . This is the problem with the MA forum. Too many jackasses. Sorry Link to comment Share on other sites More sharing options...
PhineasC Posted February 14, 2012 Share Posted February 14, 2012 Sorry Can I get an elevation check, please? Link to comment Share on other sites More sharing options...
Fozz Posted February 14, 2012 Share Posted February 14, 2012 Can I get an elevation check, please? Less than Oakland Link to comment Share on other sites More sharing options...
tcutter Posted February 14, 2012 Share Posted February 14, 2012 The 18z model runs? My understanding is that these point and click forecasts are direct outputs of model data with little or no human intervention. Supposedly not anymore....................... I debated whether or not to try and go through all this again, but I'll try. First, in terms of total volume of observations, you're first statement is dead wrong. The radiosonde network only forms a very tiny portion of the global observing system (though it is hugely important). I have no idea what you mean when you say that the radiosonde data is "out of date" for 6z and 18z. At NCEP, we (currently) use a 3D analysis scheme with a 6 hour time window. If you use 12z as an example, we only assimilate observations that are taken between 09z and 15z, for that given analysis. There are ways to use observations within a longer time window, and actually take their time information (and propagation) into account (4DVAR), but we'll save that subject for thread. In terms of aircraft data, your comment is sort of true if you focus only on a small portion of the globe (i.e. CONUS). I took the liberty to get a rough estimate for the number of aircraft observations that we assimilated, by cycle, from 00z-18z today, and here are the approximate numbers: 67610, 52744, 53490, and 72177.....not as much disparity as people think. This is partly because these are global numbers. However, we actually get a lot of observations from package carriers that operate aircraft (think Fedex and UPS). Here is an example of a distribution from 06z on the 24th: This is only for the cruise altitude (150-300 mb) observations that were taken;, nor have I shown the obs for type 231 (that's why the numbers don't match up with what I provided above). Keep in mind that for any given 06h window, we basically have global observation coverage (tons and tons of multi-channel IR, MW and visible satellite data, GPS radio occultations from space, satellite derived atmospheric motion vectors [satellite winds], surface observations, ships/buoys, aircraft, wind profiler, radar, in addition to the radiosonde network). Because of hyperspectral satellites, the number of observations we have access to for any given cycle is on the order of hundreds of millions (though there is a lot of redundant information)....and the number assimilated is on the order of several million (I'm too lazy and tired to get the exact counts right now). Back on topic....now, I feel that the biggest differences between 06z/18z and 00z/12z can be seen for individual, high impact events....where better in-situ sampling can make a difference [example: some critical shortwave that is important for some downstream development or something entering the North American Raob network]. I personally don't think that in a time mean sense the skill between any of the cycles is statistically significant (mind you, this certainly wasn't always the case). However, every time I try to put together evidence to make my case, I can always find metrics, levels, or periods that seem to suggest one thing is better than the other. We use AC scores too much, so bear with me. Here is a long time series showing the GFS AC at 500 hPa for all four cycles (the top panel is a three month moving average, and bottom panel shows the difference relative to 00z): Notice how before 2008 that the red and blue curves are almost exclusively below the 0 line, but within the past few years the red/blue do poke above the zero difference line (and the spread has shrunk somewhat). I can assure you that the differences (at least from the middle of 2007 and beyond) are not statistically significant. Also note that for the last year that 12z seems to be doing a little better than the other cycles. However, to argue against myself.....and as the above plot would suggest, you can find individual periods that would seem to suggest some cycles are better than others (here is one recent example....a small sample size where the differences are not statistically significant): I don't have time to do an extremely thorough evaluation using other metrics/levels, etc., but the bottom line (in my opinion) is this notion of 06/18z versus 00/12z is more myth than fact (at least in the recent NWP era, and in a time-mean sense). Another thing to keep in mind, these metrics are looking at forecasts of the same length (120h forecasts in this case). In the short range, an updated forecast is always going to be more skillful than an older forecast valid at the same time because of the assimilation of observations. I'll use a 2 day forecast as an example: The 42h forecast initialized at 6z is going to be better than the 48h forecast initialized at 0z (regardless of what you think of 6/18z in general). In fact, if no observations were assimilated at all at 6z, the two forecasts would be identical (since the assimilation scheme is an update to a short term guess, or 06hr NWP forecast). Link to comment Share on other sites More sharing options...
Ian Posted February 14, 2012 Share Posted February 14, 2012 DGEX baby. Shows a big low just SE of us. the dgex is the nam on psychedelic mushrooms Link to comment Share on other sites More sharing options...
PhineasC Posted February 14, 2012 Share Posted February 14, 2012 dtk is really good at owning weenies but I have to think it is sort of like a normal person yelling at a kindergartner about the value of low-risk stocks and bonds after said child asks for money to buy some ice cream. Link to comment Share on other sites More sharing options...
PhineasC Posted February 14, 2012 Share Posted February 14, 2012 the dgex is the nam on psychedelic mushrooms Hard to believe some dude at NOAA got paid to code that beast. Link to comment Share on other sites More sharing options...
PhineasC Posted February 14, 2012 Share Posted February 14, 2012 Less than Oakland The lake isn't frozen! That sucks! Link to comment Share on other sites More sharing options...
Fozz Posted February 14, 2012 Share Posted February 14, 2012 The lake isn't frozen! That sucks! Sucks to be you. Link to comment Share on other sites More sharing options...
MidlothianWX Posted February 14, 2012 Share Posted February 14, 2012 Supposedly not anymore....................... I believe he was just referring to the fact that the NWS zone forecasts are computer outputs. Nothing about the 6z/18z vs 0z/12z debate. Link to comment Share on other sites More sharing options...
tcutter Posted February 14, 2012 Share Posted February 14, 2012 I believe he was just referring to the fact that the NWS zone forecasts are computer outputs. Nothing about the 6z/18z vs 0z/12z debate. i really should have posted the original quote that dtk replied to........sorry about that Well, there is less available data for the 6z and 18z (particularly the 6z) models to ingest. Also, the radiosonde data is a bit out of date for the 6z and 18z runs. Also, with the 6z run, there are few aircraft in the sky in the middle of the night (outside of cross-country red eyes), so there is not much aircraft data for the models to ingest. I would be interested to see a statistical analysis of the 0z/12z runs versus the 6z/18z runs, though. I feel like the difference probably isn't all that great and, instead, we generally just say that the 6z or 18z run is trash just because we don't like it! EDIT: Disregard this and look at dtk's post below. Link to comment Share on other sites More sharing options...
Ian Posted February 14, 2012 Share Posted February 14, 2012 it would be kinda funny if the carolinas got a mecs then winter ended Link to comment Share on other sites More sharing options...
ravensrule Posted February 14, 2012 Share Posted February 14, 2012 it would be kinda funny if the carolinas got a mecs then winter ended Yea about as funny as me becoming an Admin here. Link to comment Share on other sites More sharing options...
H2O Posted February 14, 2012 Share Posted February 14, 2012 lolz Link to comment Share on other sites More sharing options...
arlwx Posted February 14, 2012 Share Posted February 14, 2012 Dandelions and daffodils in February in Arlington. What's in the fuel of the planes at DCA? Link to comment Share on other sites More sharing options...
mappy Posted February 14, 2012 Share Posted February 14, 2012 So I guess everyone is hugging the Euro Link to comment Share on other sites More sharing options...
BristowWx Posted February 14, 2012 Share Posted February 14, 2012 Reading the HPC discussion it's the first time this season I have seen these words...THIS WAVE HAS THE POTENTIAL TO PRODUCE SIGNIFICANT SNOW ON ITS NORTHERN EDGE OVER THE MID ATLANTIC STATES DAY 5...has a nice ring to it...I don't even want to look at the 12z runs Link to comment Share on other sites More sharing options...
H2O Posted February 14, 2012 Share Posted February 14, 2012 So I guess everyone is hugging the Euro For 12 hours, yes. Link to comment Share on other sites More sharing options...
Fozz Posted February 14, 2012 Share Posted February 14, 2012 I guess I should've stayed up.........oh well. Let's hope this holds. Link to comment Share on other sites More sharing options...
mappy Posted February 14, 2012 Share Posted February 14, 2012 For 12 hours, yes. I mean, I guess I can see why people are hugging it Link to comment Share on other sites More sharing options...
BristowWx Posted February 14, 2012 Share Posted February 14, 2012 I mean, I guess I can see why people are hugging it If we got just half of that and it stayed snow I'll start going to church again...not this Sunday of course since I will be posting here Link to comment Share on other sites More sharing options...
MN Transplant Posted February 14, 2012 Share Posted February 14, 2012 DGEX baby. Shows a big low just SE of us. The DGEX gave us our single greatest model run in memory, so I can't hate on it. Link to comment Share on other sites More sharing options...
North Balti Zen Posted February 14, 2012 Share Posted February 14, 2012 A not so random observation...it sucks that the ignore function doesnt work on tapatalk. Re: model thread...keep us posted brad. Sent from my DROIDX Link to comment Share on other sites More sharing options...
J.Mike Posted February 14, 2012 Share Posted February 14, 2012 Randy at last can roll out the bus: Link to comment Share on other sites More sharing options...
mattie g Posted February 14, 2012 Share Posted February 14, 2012 A not so random observation...it sucks that the ignore function doesnt work on tapatalk. Re: model thread...keep us posted brad. Sent from my DROIDX Works just fine on the default Android browser in the mobile version. I likey. Link to comment Share on other sites More sharing options...
nw baltimore wx Posted February 14, 2012 Share Posted February 14, 2012 A not so random observation...it sucks that the ignore function doesnt work on tapatalk. Re: model thread...keep us posted brad. Sent from my DROIDX Unfortunately, until this threat is dead in the water, it's going to get a whole lot worse. Link to comment Share on other sites More sharing options...
mappy Posted February 14, 2012 Share Posted February 14, 2012 Unfortunately, until this threat is dead in the water, it's going to get a whole lot worse. Filter ftw Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted February 14, 2012 Share Posted February 14, 2012 dtk is really good at owning weenies but I have to think it is sort of like a normal person yelling at a kindergartner about the value of low-risk stocks and bonds after said child asks for money to buy some ice cream. Hahaha this is one of the funniest posts I've read on here in a long time Link to comment Share on other sites More sharing options...
nw baltimore wx Posted February 14, 2012 Share Posted February 14, 2012 Filter ftw Up to this point this winter I have been amused by the random, ridiculous posts, and even the reactions to them. We'll have to see how bad it gets in the real threads before I use the ignore button. I've only used it once for an un-named b, b, boy but like a train wreck, I found myself reading them anyway just for laughs. Link to comment Share on other sites More sharing options...
Bob Chill Posted February 14, 2012 Share Posted February 14, 2012 Storm mode cometh....or not. I prefer to have weenies come out of the woodwork vs crickets. If gfs is a hit @ 12z the mods are going to be busy with a quickness. Link to comment Share on other sites More sharing options...
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