Be able to predict the weather is critical to ensure you have a safe and enjoyable experience on your expedition and during other outdoor activities.
This page deals with the weather forecasts that we check in advance of departing on an expedition or other adventurous activity.
In the UK we get reasonably accurate weather forecasts 5 days in advance. But they can still change and don’t get really accurate until about 3 days before an event. Even then you can wake up on the morning of the event to find out the weather is doing something unpredictable.
That’s the beauty of living in the UK where weather fronts can sweep in from North, South, East or West.
Damp rainy blustery weather tends to sweep in off the Atlantic in the West and North West. Bitterly cold weather comes to us from the North and East often as from far away as Siberia. Warmer weather tends to come up from the South.
But don’t think that warmer weather coming from the South will make it all nice an cheery. Often when warm weather meets cold or damp weather thats when we have our worst weather as the two different weather fronts collide.
Relationship between winds and isobars
Weather Maps look a little different to the maps you usually use.
What look like contour lines are called Isobars and instead of measuring height they measure air pressure.
There are three important relationships between isobars and winds.
- The closer the isobars, the stronger the wind.
- The wind blows almost parallel to the isobars.
- The direction of the wind is such that if you stand with your back to the wind in the northern hemisphere, the pressure is lower on the left than on the right.
These make it possible to deduce the wind flow from the isobar. Have a look at BBC Bitesize Isobars for more information.
Whilst the TV news weather forecasts help to generally predict weather we try whenever possible to use more specialised Mountain Weather forecasts.
The Mountain Weather forecasts tell us what the weather may do in more specific areas and at the different heights that we will walk at as the weather in a protected valley can be very different from the weather on a mountain top. It is important to remember:
- For every 100m of climb, the temperature will drop 1⁰C
Keep an eye on the weather forecasts and ensuring you are looking at the right forecast for the area you will be in and also traveling through to get there.
Think about installing mobile apps on your phone to monitor the weather. The Red Cross and the Met Office have apps that you can set up to give you alerts if the weather is going to change for the worst. But do not forget that you may not get a good phone signal in remote areas so don’t become reliant on these apps. Also don’t forget that we don’t let you take smartphones on your expeditions.