These are the key sites which I check out the evening before and then early in the morning when I hope to fly from Fiesch, firstly to make the final decision as to whether to go at all, and secondly to get an idea of what conditions to expect, not only there but also in other places which could be relevant to XC flight planning.
I take a glance at the synoptic chart first, to be able to put everything else in context.
Then I go to the Swiss TV/radio forecast; although I have enough German to be able to understand this, if you don’t then there’s always a Google Translate version! Although the information may not be very technical, it is usually pretty accurate, and often covers key points such as the chance and timing of showers and storms later in the day, or of high cloud moving in, which can be very helpful to anticipate. Also, if valley winds are expected to be strong, this is nearly always mentioned here.
Daily and longer-term forecasts (in German), aimed at sailplane pilots, are often published by Flugplatz Schänis, located in Eastern Switzerland – close enough to be relevant to us.
The Meteoblue page for Eggishorn sets out a very basic diagram of how the weather there is expected to evolve over the course of the day.
Meteocentrale and Flugbasis charts show current and forecast differences in atmospheric pressure across the Swiss Alps. The importance of this parameter is explained on the föhn page. When the pressure differences are excessive, it won’t be safe to fly around Fiesch, so there’s then little point in looking at more specific information.
The next feature which I assess is wind, starting with the Flugbasis map of predictions of wind speed and direction at various altitudes over the course of the day, which I often compare with the Meteoblue wind page, where a huge range of different levels is displayed. I consider the figures for 3000m to have the most important influence on overall flying conditions, e.g. large-scale headwinds/tailwinds and turbulence, followed by 2000m for the strength of valley flows. Observations from Meteoswiss weather stations are worth a detailed look, for information about wind speed and direction all over Switzerland. Clicking on each arrow brings up not only the history at each location but also a forecast until the end of the next day. More stations are shown on SpotAir, with previous figures, but no predictions. Eggishorn and the Grimsel Hospiz are the most important, followed closely by Ulrichen and Visp; then Gütsch (above Andermatt), Crap Masegn, and Chur are relevant if you hope for a flight over the passes. Don’t worry if the values for Eggishorn show unflyable winds early in the morning; this is typical!
Flugbasis also provides a emagramme, with colour coded lapse rates to facilitate rapid interpretation, but as the measurements are of the free atmosphere in the flatlands several hours previously, you can ignore the wind numbers, and the local humidity and temperature profile may be completely unrepresentative; e.g. after a local downpour the night before (not unusual in the flying season), it may take until midday for the consequent moisture to evaporate and base to rise above takeoff, even in August. If I am concerned about the risk of high cirrus spoiling an otherwise favourable day, I look at their cloud cover forecast and check the “hoch” button to show cloud over 6000m.
RASP for Europe may be worth a look, particularly for an indication of likely thermal strength over the course of the day, but I have often found that the way that things actually turn out is quite different from the predictions here.
If precipitation could be an issue, my favourite chart for an idea of when and where this can be expected is on Search.ch.
It may be useful to check out the local webcams, e.g. if there is cloud around which is expected to clear. The Fiescheralp 3600 panorama includes the main Heimat launch area, as well as flags and a windsock, so you may be able to see gliders laid out there or even airborne.
Finally – although this is not a weather site – I check the Daily Airspace Bulletin for Switzerland for the status of the Sion TMA and any other relevant information, e.g. temporary restrictions which can sometimes be imposed.
A case study provides a real-life example setting out the way that I put this scheme into practice in the planning of a flight on 26th June 2017, followed by an account of how things actually turned out.