This might help explain how ECMWF calculates the surface wind and gusts speeds.

https://confluence.ecmwf.int/display/FUG/9.3+Surface+Wind

In my view, this is not a perfect relationship for gusts and I have seen many situations where the forecast gust speed has been over/under estimated.

Hi @marekd @ivo

I have a question related to the data point spacing on the Route Cross Section and ECMWF resolution?

Out of curiosity, I was looking at the data point spacing along the Route Cross Section window and determined that the distance spacing came out to approx 11km (or 5 data points across 53-55km). This was roughly the same for near the equator and close to the pole.

The ECMWF state a grid point resolution of ~9km (as per Windy info window) for the Hi-Res model.

@marekd , are you sampling actual data points along the cross section path OR interpolating the data at an increased spacing (~11km)?

Regards Stitch

@Gkikas-LGPZ @marekd

I too would like to see the 250hpa wind barbs added to the IFR cross section window - this flight level "FL340" is very useful like FL390 for commercial aircraft operations.

Regards

@marekd ,

I'm loving it :)

Just had to get my head in the right space wrt ISA+/- . After a quick bit of Googling I can see the benefits of ISA esp with the tropopause highlighted and areas of potential instability/lower level inversions & cold/warm air advection. Neat!

Are the bottom 2 rows "cloud base height" & "cloud top height"?

I can't wait to get my hands on the Beta product......great work!!!!!!

@marekd

Is it possible at your end (coding wise) to add the height of the terrain to the fcst freezing height which should then give the true freezing height abv sea level?

Thx

Hi @marekd ,

could you check the "Freezing Level" line/trace in the cross-section display for the correct plotted height?

I have attached a screen shot (below) showing the EC forecast freezing height at Cootamundra (see picker) as 3000ft.
The cross-section freezing height line is up near the 2000m/6000ft level at the same point. The height of the topography is ~420m.

It doesn't look right????

![alt text](

Thankyou @marekd for the updated VFR display.

I greatly appreciate the work you (and the team) are putting into this product - which makes my work a little bit easier :)

I would also like to see "range rings" added as an overlay option.

With a settings feature which would nominate the number of rings and user nominated radial distances. And also include an option to display the user nominated set-up at a number of selected locations.

I have an interest in knowing when storm systems are nearing (or are forecast to penetrate) set distances from a number of locations of interest. This covers thunderstorms and regions of stronger winds assoc with tropical storms/cyclones.

Thx

@marekd @ivo

Hi guys, on your VFR route cross-section, and I right in saying that the highest "Dew-point spread" value presented is 5°C?

Could you increase the highest value to say 12°???

This would give an estimated cloud base height range [when looking at boundary layer cloud physics] up to ~5000ft (or up to the CAVOK cloud base height) when using the following rule....." The difference between the dry adiabatic lapse rate and the rate at which the dew point drops is around 8 °C per 1,000 m. Given a difference in temperature and dew point readings on the ground, one can easily find the LCL by multiplying the difference by 125 m/°C (410ft/C°) - from Wikipedia".

Thx Craig

@marekd @ivo

Another comment that I wanted to add.....

Again with VFR option, and in this case concerning Tstorms:
1/ The RH as a proxy for cloud may not always work for cellular convective situations. I have marked out specific regions where the EC model is indicating a line of TStorms on the Rain/Tstorm layer and the Cloud Top layer.....however the RH display in the Route slice only presents cloud below 6000ft. NB: this is consistent with the RH fields found within the area display when you ascend and descend through the available layers. The cloud top layer shows a distinct line of elevated cloud abv 50k ft and would be best avoided.
NOTE: I read in your comments that you will be attempting to add an IFR option for the upper level fields. Could you include a graphical feature OR a line along the bottom of the cross section highlighting "Cloud Top" values???

I would also support upper level isotach lines showing jet streams (80/120/160kt etc) and regions of significant vertical wind shear.

2/ A comment regarding the weather/rainfall along the cross section.....the users need to be aware that the rainfall towers/weather(in this case TS's) are for the previous 3hrs hours from the forecast time. I have highlighted this in top image. Just so the user is not critical of the model output when they see rain/weather at a distance point along the route following a weather system OR think that the weather system providing the precip is some x100km wide.

3/ The cloud base....I'm not a great fan of this field (cloud > SCT) when in the case of these tropical Tstorm situations (see above) the cloud base forecast is >8000-12000ft - which is not the case for this region. I like the addition of the DewPoint spread which as least gives an approximation potential cloud base (1-8 Oktas) -- DewPointSpreadx400ft - and again would be better suited to any VFR pilot.

AND finally.........I can see the benefit of "Relative Wind" vectors from a flight planning perspective. But I would also favour "Absolute Wind" vectors from a forecasting perspective. And the official forecasts are all in Real/Absolute wind directions which would make it easier to evaluate the Windy forecast against other official forecasts.

Thanks for the all the effort.........I look forward to utilising this feature.