OSUmetstud Posted February 4, 2016 Share Posted February 4, 2016 Hi guys, This has been a discussion in the office about off hour runs. Less sounding data etc. I've looked at skill scores and there is no appreciable difference between 06z and 18z runs. Does anyone have any thoughts? Anecdotes? Link to comment Share on other sites More sharing options...
Heisy Posted February 4, 2016 Share Posted February 4, 2016 Always thought the "6z/18z runs suck" theory was just "bro-science" .... Link to comment Share on other sites More sharing options...
codfishsnowman Posted February 4, 2016 Share Posted February 4, 2016 Hi guys, This has been a discussion in the office about off hour runs. Less sounding data etc. I've looked at skill scores and there is no appreciable difference between 06z and 18z runs. Does anyone have any thoughts? Anecdotes? its fun to pick on those runs Link to comment Share on other sites More sharing options...
OSUmetstud Posted February 4, 2016 Author Share Posted February 4, 2016 Always thought the "6z/18z runs suck" theory was just "bro-science" ... Many mets(including some good ones i've talked to) give those runs less weights or even go as far as effectively discarding them. I think it's based on old science. But I wanted to hear from other mets on the topic. Link to comment Share on other sites More sharing options...
ORH_wxman Posted February 4, 2016 Share Posted February 4, 2016 It used to be they suffered from lack of up to date RAOB data....but now with our increased satellite data it's become much less of a problem. So yeah, I'm in the camp that it is based mostly on older science...that said, there's probably at least a little truth to it in certain situations where maybe there is a really strong shortwave over land. NOAA will still due special RAOB launches when there's a very high impact weather threat, so clearly they do believe that RAOB data is the best even though satellites have largely closed the gap. Link to comment Share on other sites More sharing options...
Typhoon Tip Posted February 4, 2016 Share Posted February 4, 2016 Walt Drag (NWS) told me once to treat them like just another ensemble member, but that was like 10 years ago... As Will was saying, they may be improved significantly with other assimilation and satellite assistance. Having said that, assimilation can influence the runs ... interestingly from time to time. Nothing really beats hard measured raob data in the initializations - I also once read that the initialization of the those off hour runs was based upon the grid values of the first 6 hours of the 00z and 12z. Not sure if that is still true - or was... Link to comment Share on other sites More sharing options...
dendrite Posted February 4, 2016 Share Posted February 4, 2016 00z seems to statistically score the best for whatever reason at H5 on the GFS. Until recently 6z and 18z had slightly worse scores than 00z and 12z, but being 6hrs closer to T-0 overcomes that. IOW, the 6z and 18z runs have value...especially if all of the players are on the field and we're not trying to sample Pacific s/w's. Link to comment Share on other sites More sharing options...
apm Posted February 4, 2016 Share Posted February 4, 2016 A question: Does a 6 hour time advantage make up for GFS's generally lower verification scores vs the Euro? In other words how does the 18z GFS, in general, compare with the prior 12z Euro (or 6z vs 0z)? At some point it must do better, right? e.g. for a 6 hour vs a 12 hour forecast? Link to comment Share on other sites More sharing options...
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