validdate;weather_text_en:str 2019-04-08T00:00:00Z;Today after sunrise the sky will be overcast. In the afternoon it will be mostly sunny. About 4 hours of sunshine are predicted. It stays very balmy with temperatures between 9°C and 16°C. After daybreak there is a slight northeasterly wind which shifts afterwards to a slight southerly wind. In the late evening the sky is partly cloudy, in the second half of the night dense mist may appear.
This parameter returns the visibility in kilometers. Fog conditions occur if the visibility is less than 1km.
This index gives you an idea whether dew or rime will occur. Dew or rime forms if the surface cools down quicker than the surrounding air, which causes condensation onto the surface at high relative humidities. Dew and rime are very sensitive to solar radiation and disappear quickly as the surface warms. Rime is the frozen version of dew.
0: neither dew nor rime, 1: dew, -1: rime
Dew or rime forecast for the next two days along with the expected temperatures. On the 8th March, 2017, some dew was expected from 3 to 5 a.m. This was expected to be followed by some rime one hour later, when the temperature dropped significantly:
Icing is absolutely critical in aviation and in-flight icing on planes are the cause of multiple near-accidents or even crashes. Consequently, it is crucial for aviation to have reliable icing forecasts predicting the expected occurrence of icing on different altitudes and allowing for early circumnavigation.
Below showing an example screenshot of the icing potential at 500hPa displayed via the powerful Meteomatics WMS interface. Very well visible the icing potential along the cold front associated with the strong low pressure system West of Ireland.
The planetary boundary layer (PBL) height is determined by identifying the height, where big wind direction changes, local minima of wind speed, local maxima of temperature, high temperature increases (inversion) or high potential temperature increases occur.
The freezing level parameter provides the altitude where the temperature equals 0 °C. If the freezing level is below ground, the return value is -666. In case of strong convection, the height of the freezing level correlates with the size of hail observed at the surface, since it determines the melting area for falling hail.
This index provides the average wind speed at 10, 50 or 200 hPa between 60°N and 90°N and thus indicates the strength of the stratospheric polar vortex during the polar winter. The SPV index provides a measure of the circumpolar vortex strength and indirectly relates to a risk of cooling temperatures near the surface in the northern hemisphere, if decreasing below zero. If the index becomes negative, the vortex disruption is such that a “split" or strong “displacement" is under way, possibly weakening the jet stream in the troposphere.
Precipitation in the form of freezing rain or wet snow can freeze onto overland power lines. With the increase in diameter and mass come a bigger air resistance and a lower resonance frequency. Strong wind over a sufficient amount of time could then excite the conductors to oscillate near their resonance frequency (sometimes referred to as gallop) and thereby damage the lines and masts.
A power line oscillation warning for the past 24 hours can be queried with the following parameter:
The warning is binary with 1 corresponding to a warning and 0 to an all clear. Not taken into account are things like constructional details of the power lines or the Joule heat emitted by active power lines.
On March 24 2016, there was a power outage in Halton Hills due to galloping power lines, which is exemplified by the following time series:
The soaring-index is used for an estimation of the thermal situation. It is useful for paraglider and other sport pilots. A higher soaring-index also shows a greater chance of showers and thunderstorms, as it is a measure of the lift caused by convective clouds. The soaring index is independent of altitude, as it is computed with variables in different altitudes.
The leisure index combines different weather parameters and assesses if weather conditions are favorable for certain outdoor activities or not. The index ranges from 0 to 1, where 1 means that conditions are perfect for the queried activity at the queried point in time (i.e. the parameter is instantaneous). The indices are based on a combination of precipitation, temperature, wind speed, wind gusts, humidity, sunshine duration, snow cover, visibility and fog.
Available activities: ballooning, bbq, beach, biking, climbing, fishing, gardening, gliding, hiking, hunting, sailing, skiing, tv
This index combines several weather parameters like temperature, wind speed, humidity and precipitation and assesses how favorable these weather conditions are for catching a cold. The index takes values from 1 to 100, where higher values indicate higher risks.
Time series showing the cold index for St. Gallen on the 17th of January, 2020:
Gives the probability for the occurrence of windshield icing for cars. This index combines information about temperature, humidity, wind speed and other parameters and yields a probability in the range of 0-100 %. In addition, it is possible to specify an inclination between 0° (flat) and 90° (vertical) of the windshield - the default value is 50°.
Time series showing the probability for windshield icing in Zurich:
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