The USAF has a useful site that also publishes some of the UK met office products
Here These give forecast RH at various altitudes so you can deduce probable cloud density. Also, the NOAA site IO referenced does do Skew-Ts. You select a location and then it gives you a page where you can select 'Soundings'. These are forecast soundings and can be displayed as tabular data or as a skew-T (or both)