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The "sky cover" represents the percentage of sky obscured by clouds, as would be visible to an observer (or weather instrument) at the Earth's surface. The most direct reference I could find to this quantity was in this archived presentation from the American Meteorological Society's 2014 Annual Meeting: "The United States Federal Meteorological Handbook (...


3

Such simple algorithms are empirical and for the same reason very local, so depending on your location they can have very bad performance. In the other hand, some people argue that properly calibrated they can be over 90% accurate. Most of them are based in the Zambretti algorithm or some variant of it. This algorithm was originally implemented in a ...


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I agree that the PoP = C x A that we see on a lot of websites leaves something to be desired. It gets across the loose idea that the definition involves the area affected as well as the probability of occurrence, which is fine for most casual readers but can be frustrating for more inquisitive minds. How much are the confidence and the area estimated from ...


2

The (statistical) variation is not the same as the gradient. The gradient is a measure how things change from here to a nearby point, or from now to a point in the near future. The variation, on the other hand, just says how often wind speeds of different magnitude happen. For example: If the wind were to blow at exactly 30 km/h all the time, then the ...


2

A small meteor/asteroid impact might trigger a nuclear winter, but it would be registered by people and it would be very unlikely to trigger an ice age unless the impact created a very large amount of dust in the atmosphere. The dust would need to stay in the atmosphere for a decade or more to trigger an ice age. A natural nuclear explosion cannot be very ...


2

(not an answer, too long for a comment) Strictly speaking, the answer is yes, since the temperature generally increases during the day and falls at night (and local time is a local variable), the barometric pressure and humidity can indicate if a storm is coming (there were some really old fashioned weather prediction "clocks" that did this). Realistically, ...


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Maybe you can use infrared satellite images to get the cloud-top temperatures and estimate the height of them over vertical temperature profiles (e.g. radiosondes). But this ís just workingg for the clouds at the top. You can't see what's beneath them unfortunately.


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As @Erik notes, the answer to your question is vacuously "yes". Digging a little deeper, we can break this into two questions: Given the vast amount of weather data available (http://opendata.stackexchange.com/questions/10154/sources-of-weather-data/10155), is it possible to find correlations (either linear or non-linear) between known data such as ...


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The GSD file is just a text (ASCII) file, which you can read with almost anything you want. Since you are using python I would recommend looking at Pandas and especially the pandas.read_csv functionality. I am using this URL as an example now: https://rucsoundings.noaa.gov/get_soundings.cgi?data_source=Op40&latest=latest&start_year=2019&...


1

Your question is extremely broad and it would be comprehensive to answer in detail. How it is done varies from one application to another. But in general, all weather forecasts come from a numerical prediction which is based on an analysis. The analysis is created by combining a prior (the previous forecast) with observations. There are many ways this can be ...


1

You can build a machine learning algorithm with skill but you will need several parameters such as day of year, time of day, cloud cover, wind speed, and precipitation. However, keep in mind that your algorithm will need to be trained on several years of previous data. For projects like this, you typically want about 5 years of observations to "train" the ...


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Predictability of weather and climate is currently an active and lively research topic. I will try to giove some (very) brief information on how it is normally done. The best idea would be to use a weather (atmospheric) model, which is a numerical model that solves the Navier-Stokes Equations to bring prognostic information of the atmospheric state, for ...


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There are (at least) two factors involved here, before we even get to questions of chaos theory. First, thanks to weather satellites and other sensor improvements, we can measure the initial conditions much more accurately. (One can do a halfway decent 3-day forecast for the West Coast just by eyeballing the GOES West images.) Second, we have greatly ...


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The coordinates defined in Global Forecast System (GFS -0.5º Degree) data defined somewhat unusual. In the GFS, longitudes and latitude contains 720 and 361 values respectively. Therefore to convert them to a common geographic coordinate system follow the procedure below: Suppose you are looking for index of coordinate pairs (36.5, -78.5) in the GFS data: ...


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