Very interesting. For US-centric SLP/MSLP calculaions I would have thought that 12 hour temp averages would always be used; Again, from Dr. Burch: *T (avg) = [ T(0h) + T(-12h) ] ÷ 2. *He did a study on this comparing QFF results using T(0h) and another data set using T(avg) and remarks*: * "..[our] study is remarkable evidence that we must use the average temperature over the past 12h when correcting QNH to get QFF".
Why would one want to convert QFF/SLP back down to station pressure? I don't have a Davis weather station but could it be that Davis VP2 consoles send SLP to WeeWX and then WeeWX converts it back to station pressure so that WeeWX can calculate both Altimeter and SLP??. If a Davis console is set to zero elevation what is sent to WeeWX?. I am guessing raw station pressure and then again, WeeWX calculates Altimeter and SLP. from station pressure. Did I get that right? On Wednesday, July 5, 2023 at 10:03:33 AM UTC-4 Karen K wrote: > [email protected] schrieb am Mittwoch, 5. Juli 2023 um 15:37:16 UTC+2: > > Interesting comment that WeeWX uses current temperature only. Perhaps Tom > can confirm. Does WeeWX use current temp or the 12 hour average? > > > To be precise: It uses the current temperature, if it calculates the > sealevel pressure out of the station pressure. It uses the temperature 12 > hours ago together with the current temperature, if it calculates the > station pressure out of the sealevel pressure. > > pressure to barometer from wxxtypes.py: > > [image: barometer-from-pressure.png] > > pressure from barometer from wxxtypes.py: > [image: pressure-from-barometer.png] > > (Sorry, I found no other way than to use a screenshot.) > -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/c9a8709d-5d3e-4120-9385-f35284dcd9c7n%40googlegroups.com.
