#Mountain weather indicator clouds clear plus

A video also shows you the latest BBC TV forecast.Įnjoy postcode-based forecasting here, plus a ‘feels like’ facility (how it will actually feel due to humidity, temperature and windspeed). There's also a regional map with a cloud-cover prediction display that can be manually advanced in three-hour increments. Simple to use, this website has access to relatively local data based on your postcode, including temperature, cloud cover, humidity, windspeed and pressure. Using a combination of information from weather websites and local knowledge is definitely a good way of obtaining a ‘best guess’ of what the weather holds for the next few hours Online weather forecasts BBC Weather There is a strong correlation between good seeing and low wind speeds, irrespective of the atmospheric pressure. Home weather stations can also tell you the current pressure, wind direction and speed. They are limited to daytime availability, however.īarometric pressure charts are useful weather indicators, with high pressure indicating clearer conditions and lower pressure warning of unsettled conditions, cloud and stronger winds. They’re better than infrared images for showing low-level cloud, because these are more reflective than the land or sea below. Visual light images show light reflected from the Earth and cloud tops back towards the satellite. On the other hand, at least they’re available 24 hours a day. Infrared images aren’t suitable for showing low-lying cloud, because low clouds are at a similar temperature to the Earth’s surface and won’t show up. Rain falls when cloud temperatures drop and reach the dew point, so lighter colours in infrared images indicate cooler cloud tops and the increased likelihood of a shower.

Warmer objects radiate more infrared radiation than cooler objects, so these images can be used to determine temperature.ĭarker areas show warmer temperatures and lighter areas show cooler temperatures.Īn astronomer’s nightmare: a Met Office infrared image showing clouds across the UK. They show the infrared energy radiated from the cloud tops and the Earth’s surface.

They can be animated to give a view of what has gone before, indicating what is likely to follow. Satellite images are useful for determining what the cloud cover is going to be like later in an evening. Weather websites have several useful displays. As the air descends on the north side of the Downs it will warm and dry out, leading to the cloud breaking up once again. The air then cools as it rises over the South Downs, forming clouds. On a typical summer’s day, with the wind coming off the sea, the skies will be clear over the coast. Unfortunately, forecasting is not an exact science and local conditions need to be factored in.įor example, the location where this is being written – at the foot of the South Downs – can have very different conditions to those to the north and south. Forecasting on the day is the most reliable method as cloud cover changes very quickly. One website even predicts the seeing for your area: The lower the seeing in arcseconds, the better. Satellite images are handy for showing the current atmospheric conditions in both visual and infrared light, and how they may develop over the following hours. Weather apps - particularly those created for astronomers - are great for planning ahead, although good weather doesnt always mean good observing conditions.

Mountain weather indicator clouds clear