Probability of precipitation type

Based on the IFS atmospheric model ensemble with 1 control and 50 perturbed forecasts, the probability of precipitation type is calculated from the precipitation type variable which has 6 different precipitation categories: rain, freezing rain, snow, wet snow, sleet and ice pellets. The precipitation rate variable was used to classify the probabilities in different precipitation intensities.

Description & Technical Information

Description

The instantaneous probability of precipitation type (%), shown for a given site, depicts the temporal evolution of precipitation type probabilities (rain, sleet, wetsnow, snow, freezing rain and ice pellets) for a specific location in bar chart format, to help the user make better decisions regarding particular events.

The probability of precipitation type is displayed combined with the instantaneous total precipitation rate (another IFS variable) to provide for example an indication of potential freezing rain events and their likely severity, heavy snowfalls, etc. In this aspect, each precipitation type is also divided in 3 different categories depending on the precipitation rate, from one minimum value to 0.2 mm/h (low intensity), from 0.2 to 1 mm/h (medium intensity) and greater to 1 mm/h (high intensity).

Ideally, this product is plotted as a meteogram, showing the probabilities of each precipitation type for a specific location

The probabilities of each precipitation type depending on three precipitation rate categories are provided separately in grib format:

– Probability of rain – low intensity (0.12-0.2 mm/h)
– Probability of rain – medium intensity (0.2-1 mm/h)
– Probability of rain – high intensity (>1 mm/h)
– Probability of freezing rain – low intensity (0.05-0.2 mm/h)
– Probability of freezing rain – medium intensity (0.2-1 mm/h)
– Probability of freezing rain – high intensity (>1 mm/h)
– Probability of snow – low intensity (0.05-0.2 mm/h)
– Probability of snow – medium intensity (0.2-1 mm/h)
– Probability of snow – high intensity (>1 mm/h)
– Probability of wet snow – low intensity (0.05-0.2 mm/h)
– Probability of wet snow – medium intensity (0.2-1 mm/h)
– Probability of wet snow – high intensity (>1 mm/h)
– Probability of sleet – low intensity (0.1-0.2 mm/h)
– Probability of sleet – medium intensity (0.2-1 mm/h)
– Probability of sleet – high intensity (>1 mm/h)
– Probability of icepellets – low intensity (0.05-0.2 mm/h)
– Probability of icepellets – medium intensity (0.2-1 mm/h)
– Probability of icepellets – high intensity (>1 mm/h)

Technical information

Hazard , ,
Coverage Global
Horizon 6 days
Time Resolution 3-hourly up to 144 h lead time
Spatial Resolution 0.2° x 0.2° lat/lon grid (~18 km)
Update Updated twice a day following either the 00 UTC or the 12 UTC ECMWF forecast release
Nature Raster Maps
Availability , , ,

Model or Algorithm