Description of weather overlays
Wind: Average wind 10 meters above the surface (or at selected pressure level). Actual wind at the ground is influenced by many factors like mountains, cities, convective clouds and thermal effects.
Wind gusts: Wind gusts 10 meters above the surface in the last 3 hours. Actual wind at the ground is influenced by so many factors like mountains, cities and thermal effects. ECMWF model has a different method of Wind gusts computation, resulting in higher values than other models.
Temperature: Temperature 2m above the surface (or at the selected pressure level). The actual temperature is influenced by many factors like mountains, convective clouds and cities.
Clouds: Clouds and rain/snow accumulation in the last 3 hours. Please note, that rain from convective clouds can not be included in this value, therefore observe CAPE index.
Relative humidity: Relative humidity 2m above the surface (or at selected pressure level).
Cape: Convective available potential energy, represents potential energy of atmosphere and can be the indicator of forming convective clouds and storms. Values from 1000 to 2000 can indicate forming of moderate thunderstorms, and over 2000 severe ones.
Ozone: Total Column of Ozone, is a factor that influences the amount of dangerous UV radiation coming to the surface. Measured in Dobson units. Higher values mean more ozone and less UV radiation.
Cloud base: Cloud base height is an altitude of lowest cloud base above the ground, so important for pilots. Model of terrain is simplified, so caution to use this values in the mountains.
Rain Accumulation: Total rain accumulation in the next hours or days
Snow Accumulation: Total snow accumulation in the next hours or days. To estimate snow depth, we use the ratio: 1mm of rain = 1cm of snow.
Waves: Significant wave height and its period of all wave types combined (swell and wind waves). Close to the shoreline is actual height influenced by the shape of the sea bottom.
Currents: Surface sea currents as estimated for actual time. Close to the shoreline is actual value influenced by the shape of shoreline and sea bottom. Also, actual surface sea currents can be influenced by the wind.
SST: Sea surface temperature as estimated for actual time. Close to the shoreline is actual value influenced by the shape of shoreline and sea bottom, and also by wind and waves.
Wind Waves: Significant wave height of waves formed by surface wind. Close to the shoreline is actual height influenced by the shape of the sea bottom.
Swell: Significant wave height of low-frequency oceanic waves (usually travelling long distances).
Swell period: Period of swell.
Pressure: Mean sea level pressure.
Rain: Rain/snow accumulation in the last 3 hours.
Rain rate: Maximum precipitation rate in the last 3 hours. The total precipitation is calculated from the combined large-scale and convective rainfall and snowfall rates every time step and the maximum is kept since the last 3 hours.
Dewpoint: Temperature at 2m above the surface (or at selected level) at which a water vapour in the air will form dew. It is a measure of atmospheric moisture.
In the latest version of windytv there are more overlays (e.g. cloud tops, frz altitude, visibility).
So, some more descriptions needed.
Could you explain difference between:
- swell 1
- swell 2
- swell 3
The freezing altitude layer, how does that work? I am often looking at ski weather and on those sites, the current freezing altitude (frostgrenze in German, vorstgrens in Dutch) is at around 3800 meters. Yet the 'freezing level' layer shows values of 2500 to even 1900 meters for those locations, even though the current temperatures there are much higher.
Am I misinterpreting what the freezing altitude layer actually is or does? Or is the data faulty?
Are the two numbers in the wind section - gusts and sustained winds?
- how do I find the forecast for the storm Irma
@shappy4 The first number is wind direction and the second one is wind velocity (average value for last 3 hours).
Hello. What does the height of 100 meters mean? Above sea level or terrain? The navigation satellite writes that I have a height of 160 meters above sea level (160 m msl).
@IgorXXXmirror Hi, 100m layer is above model terrain. Unfortunatelly it is very coarse terrain with 9km horizontal resolution.
When using wave overlay, I see a color key indicating wave height and also boxes with values in them with either- or~ before the value. These numbers never match the color key .
What means the 330 before 64km/h?
wind direction 330 degrees (coming from NorthWest)
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I cannot see RAIN RATE in the settings ....
Is there an overview of the meteograms that Windy displays for the forecasts? I am not sure of what some of the background colors and charts mean.
@alecloudenback Me neither. I was searching for a manual to find out about the meaning of the different colors,graphs,pictograms etc....
@tz What height does surface refer to? There would technically be no wind at the surface, so it must be some standard height above the ground (whatever the common reading instrument height is). What is that height? (i.e. 2m, 10m, 20m?). I'd like to use the data to estimate wind shear at a given location and using surface (0m) is not valid.