NCEP is scheduled to change over to the new GFS model (supposedly somewhat more accurate!) on June 12, at 12Z. This change is more significant than most upgrades, partly because there are some changes to URL’s, at least for the web based downloads. Sam (Bohler) and I have been conferring on this and preparing for the changeover, and hopefully it will happen seamlessly on Wednesday. However, our testing on the “parallel” data revealed a problem with reading the sea level barometric pressure data: the 0 hour data was fine, but erroneous values were appearing starting with hour 3. This triggered an error, so we switched temporarily back to the old (still “official”) data, so we could work on the problem.
We’re actually working on that tonight, and are pretty confident we will have it fixed. However, as a precaution, I have just posted new versions of WXSIM (2019, Build 1.2) and WXSIM-Lite (2.5), which sidestep the problem by coming up with substitute pressure values. WXSIM’s is very accurate, based on the 1000 mb height (which is being read fine), temperature, and station elevation, and should not compromise the forecast in any significant way. WXSIM-Lite will simply default it to 1013 mb, BUT it’s not really used in what WXSIM-Lite does (I was grabbing it mainly for possible future use), so that should be fine. You shouldn’t even see any evidence of these substitutions, except for a brielf message in WXSIM, if your running it manually.
Again, I expect this will not even be needed, but I wanted to get out ahead of any problems!
As for Chris McMahnon’s GFS data source, I’ve communicated with him on this, and he’s using an FTP source that he thinks will not be changed. I do not know whether his script will encounter problems with that pressure value, but if it does, this WXSIM upgrade will take care of it anyway.
SO, please run www.wxsim.com/wxsimupg.exe, just in case!
Thanks, as always, for using my software!
Tom