General remarks:
With the use of the American global weather forecast model GFS different meteorological parameters can
be taken as direct model output or calculated for each grid point.
With a resolution of the model grid of 0.25 degrees, a network of 1,036,800 grid point covers the earth's surface.
Nevertheless, the model is not able to reproduce not only Central Europe's typical and diverse land surface adequately.
At a relatively small horizontal distance, valleys and mountain ranges alternate,
all of which have a decisive influence on a wide variety of weather elements;
Predicted rainfall or temperature values can not simply be transferred to any desired grid point or location.
Forecasts can only be considered as representative of a larger area, statements about precipitation or
temperature must always be made and interpreted with great caution.
Germany is covered by about 230 grid points (horizontal resolution 0.5 degrees)
or rather 920 grid points with a horizontal model resolution of 0.25 degreees.
For each of these points,
a city as close as possible was selected,
for which the different meteorological parameters are calculated and presented in tabular form.
In a similar way,
forecast data can be obtained for many cities worldwide.
Alert thresholds for various meteorological parameters:
There are no internationally valid or comparable warning criteria
above or below of which any impairment or damage to agriculture or infrastructure has to be expected.
The climates of the world are characterized by different parameters, which have typical values, ranges and variabilitites.
They range from the extremely dry and hot desert areas over humid and frost-free tropical regions to the polar areas frozen
in permafrost.
A rainfall of 10 mm within one day can be a very extraordinary event in desert areas,
but is commonplace in the mid-latitudes or in the tropics.
A temperature of 0 °C in the subtropics or tropics means the highest risk for plants and crops,
at high latitudes, however, it's like heat wave.
Especially with regard to the temperature, it would be more reasonable to set the deviation from the long-term mean
at an respective location as the relevant warning criterion, instead of the absolute values.
Nevertheless, "Wettergefahren-Frühwarnung" sets fixed limits
as alert thresholds, above or below unusual or extreme weather has to be expected
and may cause severe damage or at least is hazardous.
Warning criteria of
German Weather Service (DWD) for Germany.
Automatised weather warnings at "Wettergefahren-Frühwarnung"
For around 2800 German, European and non-European cities,
various meteorological variables are automatically calculated:
Forecast Period: 96 hours (4 days)
Issued: 00 UTC-GFS-Model Run of respective day
Forcast variable: Maximum wind gusts, daily maximum and minimum temperatures, precipitation (different intensities),
convection indices (thunderstorms), fresh snow, black ice
Update cycle: daily at 09 UTC
Maximum wind gust (kph): | Highest wind gust during forecast period (00-24 UTC) |
Daily high temperature (°C): | Maximum air temperature during forecast period (00-24 UTC) |
Daily low temperature (°C): | Minimum air temperature during forecast period (00-24 UTC) |
Precipitation 3h (mm): | Highest precipitation amount during 3 h-forecast period of respective day |
Precipitation 6h (mm): | Highest precipitation amount during 6 h-forecast period of respective day |
Precipitation 12h (mm): | Highest precipitation amount during 12 h-forecast period of respective day |
Precipitation 24h (mm): | Total precipitation amount of respective day |
Precipitation Day 1-2 (mm): | Total precipitation amount of next two days (48 h) |
Precipitation Day 1-3 (mm): | Total precipitation amount of next three days2 (7 h) |
Precipitation Day 1-4 (mm): | Total precipitation amount of next four days (96 h) |
Amount of fresh snow 24h (cm): | Total amount of snow accumulation during respective day (00-24 UTC) |
Thunderstorm: | Convection Index (SWEAT-Index) during respective day (00-24 UTC) |
Sultriness (hPa): | Maximum water vapor pressure during respective day (00-24 UTC) |
Black Ice (yes/no): | Possibility of black ice (Rain and surface temperature below 0 °C at the same time) during respective day (00-24 UTC) |
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