Weather Commander updates
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FMAP extracted from F4WX : Is there a problem with the cloud base: 3000ft appears with a black colour as if the value were higher than the surrounding clouds?
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here the same FMAP after it was read & saved in BMS
I suspect that the cells with 3000ft are over 9000ft…
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no one has been able to verify this point? Am I the only one who’s surprised to get such FMAP cards, or that FMAPs are being rebuilt in this way in Weather Commander?
In Weather Commander, the 3000 cells are probably reading the fmap wrong or getting confused about non-standard weather scenarios. F4Wx should not normally produce fmaps that make such a big jump in the clouds, as it just interpolates data form the real GRIB files …
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F4WX is not fully compatible with BMS 4.37 2 at the moment.
Maybe that’s the reason. -
@suhkoi69 Did you download the same grib2 file then drop the grib2 file on Interactive Maps and save to .fmap and then open in WC.
What do you get in that case?WC does some interesting stuff to float pressure values; It rounds everything to the nearest mb which is a massive pressure adjustment. Can be 2 inches Sea Level rise or fall. from the pressure.
Anyway can you try the grib2 file you have and drop on the Interactive Maps and save as .fmap and the load in WC? What do you get?
Interactive Map (maps.falcon-bms.com) understands the grib2 encoding.
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@ohommes good idea!
I do it -
there is also some issues with Interative Maps
below the fmap read in WC
cloud base
Fog Alt
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now I read the grib2 file given by Interactive Maps in F4WX to generate a new FMAP
I read this new FMAP in WC
cloud base
fog alt -> nothing I need to read Fmaps to BMS and save it
After saving the FMAP in BMS
cloud base
![text alternatif]( url de l’image)
fog Alt
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@suhkoi69 Can you make the grib2 available? I am starting to suspect WC is broken.
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check this : in starting with the same grib2 generated from Interactive Maps
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@suhkoi69 Please Generate the fmap from Interactive maps.
Drop the grib2 file and click save button and take the saved fmap from Interactive maps.Also the fact the WC has 3000 flat base is suspicious; I already noticed WC rounding everything for pressures being read in.
I am suspicious of WC at the moment.
Also F4Wx and Interactive Maps do not have to agree on the cloud base in Alt because grib2 only gives pressure levels and you need to determine the cloud base based on PRMSL, Pressure and Surface temp. I use Gas constants, Gravity, mass per mol for calculations here. If F4Wx uses something different we will not agree on the cloud base:
// prmsl, press in Pa function gfsAltFromPRES(prmsl, pres, surf_temp) { // Physics Constants const R = 8.31432; // Gas constant (N x m) / (mol x K) const M = 0.0289644; // kg/mol const g = 9.80665; // m/s^2 const st = 15.0 // Standard Temp C. // Lookup Temperature from standard atmosphere var T = gfsPres2Temp(pres / 100)+273.15; // Kelvin T = T + (15 - surf_temp); // Determine Cloud Base // pres = prmsl e ^(-gMh / RT) // h = ln(P/P0) RT / -gM var alt = (Math.log(pres/prmsl)*R*T)/(-g*M); alt *= 3.28084; // Make ft return alt; }
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@suhkoi69 Can it be that F4Wx encodes version 8 fmaps incorrectly? That is why I want you to save an fmap generated from Interactive Maps. That will save as version 8 format for the fmap that you can load into WC.
Just click the save button (on the connectivity tab) after you dropped the grib2 file on interactive maps.
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@ohommes said in Weather Commander updates:
@suhkoi69 Please Generate the fmap from Interactive maps.
Drop the grib2 file and click save button and take the saved fmap from Interactive maps.that’s exactly what I did here : https://forum.falcon-bms.com/post/381502
below the same grib2 but read in F4WX to save FMAP
https://forum.falcon-bms.com/post/381504 -
@ohommes said in Weather Commander updates:
@suhkoi69 Can it be that F4Wx encodes version 8 fmaps incorrectly? That is why I want you to save an fmap generated from Interactive Maps. That will save as version 8 format for the fmap that you can load into WC.
Just click the save button (on the connectivity tab) after you dropped the grib2 file on interactive maps.
I already did and I mentioned you there are also some issue with cloud base & fog alt
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@suhkoi69 Can you make your grib2 available so I can test?
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@suhkoi69 Looks like all is correct and the fog alt of zero means there is none. At least that is what i understand from the format. From the video it looks like all the data is correct including the cloud base. The fact that there is that pattern. That is what is in the grib2 file. You can compile the grib2 executable and generate a csv of the fog layer and see if it matches but from what I see all looks ok.
All looks correct from what I see in the video. Why there is a sharp contrast in the south for the cloud base I don’t know. That is what I think is in the grib2 file. Could be a major cold front coming from the south where the cloud base is very low.
Can you get actual METARs / TAFs for airports in these zones? So we can check what they report.
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@ohommes I find this behavior strange …above all, if I compare with Meteoblue I don’t get the same thing
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F4WX gives something similar than Meteoblue
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@suhkoi69 I will have to study this more and correlate the grib2 data with Meteoblue. Currently busy on other stuff so I will file an Issue to keep track of it. If you have the grib2 data for me than I will save these images and do some research as to why the data doesn’t match for cloud base. Other stuff seems ok.