Drakensberg weather sites

Here are some brief and general comments on the way the weather sites work. I'm commenting because weather and climate is my day job.

Some of the weather observations made by weather services around the world are sent to satellite and from there are received by any participating institute. The rule is that you can receive data as long as you send some observations. The system is called GTS. More details here:
en.wikipedia.org/wiki/Global_Telecommunications_System



The reason all these data exchanges happen is that the main weather forecast centres need current global weather observations to make weather forecasts. The weather observations are entered into the numerical models of the atmosphere and these models are then moved forward (integrated) in time to make the forecasts. Errors in the observations are large enough for the forecasts to go horribly wrong after about 6 days.

Many institutions around the world make forecasts from these models. This is where the forecasts on many of these sites are from. The models are global in extent because it only takes a few days the weather in one region to influence the weather in another region (the butterly flapping its wings story, although it was a seagul in the original paper by Ed Lorenz).

In the home region of the institution, a limited area model covering the nearby region will also be run at much finer space and time scales. For example, the Norwegians will run a regional or limited area model over NW Europe. But the forecasts for the Berg from Norway will be from their coarse resolution model (i.e. big grid boxes with poorly resolved topography).

The modelling groups are basically in competition with each other to produce the best forecasts. This is one reason they make their forecasts available.

What I don't know is how well these foreign models do in comparison with the locally produced SAWS forecasts. Local should be better because they can tune their regional/limited area model to the region and also run their own models at a resolution that resolves the topography - especially important for the Berg. But I don't know if this is the case. I do know that SAWS and other met services in Africa make heavy use of the foreign numerical model forecasts.

Thanx for the heads up on how this operates.

Weather is major factor in my work (architectural and landscape photographer) and having the right information helps in making decisions as to whether i shoot or not. Being in a coastal area though, the weather is often uncertain, especially in summer, makes my life hell!

I see www.mountain-forecast.com have added more peaks to their list.

It seems that my photo of Popple Peak has managed to find its way onto Mountain Forecast - no credit given or anything

They got it off the wiki article I wrote some time back, I did read the licensing agreement at the time and it does provide for the photo to be shared, but it requires that credit is given to the photographer when it is shared. My objection isn't to them using my photo, just the fact that there is no acknowledgement of who took it...

Any way, joys of the computerised world we live in...

Thanks for passing the warning on

Its odd - SAWS has heavy rain and thunderstorms, yr.no has almost perfect weather.

Based on past experience SAWS is usually wrong though, so lets hope for good weather...