Forecasting Cloud height and amount

[MBN]

Hi all,

I'm interested in what resources and tools are available for cloud forecasts. I go to the snow (typically Ruapehu), and it is only cloud at the wrong level that is a real problem. Skiing is between Top elevation‎: ‎2,300 m (7,546 ft) and Base elevation‎: ‎1,630 m (5,348 ft).

I note yr.no has some forecasts for high, medium, low cloud (eg https://www.yr.no/place/New_Zealand/Man ... ailed.html. How good are these? What height is meant by low medium or high?

I also was introduced to the RASP site http://rasp.nz/rasp/listForecasts.php?region=NZNORTH_C , where if you click through a date, then to Upper Air Soundings for a nearby location such as Taumaranui, you can see the time and level and coverage of cloud. Are these likely to be too far away from the mountain to be relevant?

Other sites or thoughts?

[TonyT]

Because cloud at any given point is so largely influenced by the topography near (and not so near) it, forecasting cloud accurately is very difficult for models. You really need a very fine grid spacing, which then demands a fine resolution of temperature, moisture and wind input from the coarser grid of the global models. In other words its probably unrealistic to expect model output to give you good cloud forecasts with the accuracy you need unless you can run a very fine resolution mess/micro scale model.

So, you use other techniques - local knowledge, a basic understanding of cloud formation processes - lapse rates, vertical motion, moisture advection, topographic effects etc. I would suggest your best bet is a couple of sky cameras installed on our near the mountain, and a discipline of watching them every day and relating what you see to the broader scale picture the model data gives you. Combine that with some long chats with locals who have been watching the skies in that area for a lifetime.