Weather information

In the current situation the dust flag in the TCS is set to ``high'' in the case the staff on duty considers the weather to be dusty. Specifically, setting the flag to high lowers the wind levels to close the side-ports and lower hatch, and to close the telescope completely. This visual determination is of course not a very objective measure, but there is also no well established level that defines which level is too high. It was considered to be better to have at least a specific level which is formally considered to be dusty, where a value of 20 $\mu gr/m^3$ as provided by the TNG aerosol measurements was noted to be a rather conservative indication of the weather being dusty. This was implemented such that the weather page, in line with other weather parameters such as wind and humidity, provides a warning message in case this value is exceeded. This still leaves the responsibility with the staff on duty to define if the weather is truly dusty and set the flag in the TCS.