Weather Forecast for Next 16 Days for Chelsea

The confidence bar shows how likely the forecast is to be correct based on ensemble output. 100% confidence (or 4 bars) means that there is good ensemble agreement for the forecasted temperature and rainfall. Less bars means that the forecast is likely to change in the next model run.

The RainRisk and SnowRisk columns show the ensemble risk for rain within this period. This can sometimes be different to the actual forecast which may appear confusing. In general, this risk tends to be lower the further out the forecast is as some ensembles may predict rain, whilst the number tends to be higher and correlate better with the forecast rainfall amount closer to the current time.

The description of the other variables shown above are as follows :-
Rain% (Rain Probability) - This is the forecast probability of rain. If rain is forecast then it will show you the percentage confidence in this. If no rain is forecast but the RainRisk is above 0 then it means that the deterministic forecast is not expecting rain, but ensembles are still showing a risk.
Storm% (Storm Probability) - This is the risk of thunderstorms in this area based on a mixture of variables.
Weather (Weather) - This is a combination of all elements displayed as a weather icon
Confidence (Forecast Confidence) - This is the forecast confidence for this timestep based on ensemble model output
Temp (2 metre Average Temperature) - This is the average temperature forecast at 2m above ground
Feels (2 metre RealFeel Temperature) - This is what the temperature will feel like based on wind speed, temperature and humidity
Rain (Rainfall) - This is the total amount of rainfall or precipitation expected from stratiform clouds in the forecast period.
Cloud (Total Cloud Cover) - This is the average cloud cover across the region in the 1 or 3hr period
Dir (10 metre Wind Direction) - This is the average wind direction recorded at 10m above ground
Speed (10 metre Wind Speed) - This is the average wind speed recorded at 10m above ground
Gust (Surface Gust Wind Speed) - This is the average gust wind speed at 10m above ground expected within the forecast period.
RH (2 metre Humidity) - This is the forecast relative humidity of the air at 2m above the ground
UV (UV Index) - This is the UV Index from 0 to 10 based on the cloud cover and strength of sunshine