Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR) Forum

snow/sleet in RAP/HRRR uses 10:1 ratio

Posted By: Stan Benjamin
Date: 21-February-14 1718Z

Hello RAP/HRRR users, a clarification: The snow accumulation fields for RAP and HRRR combine all snow/sleet/graupel precipitation (explicitly forecast) and assume a 10:1 ratio between snow and water equivalent. So the snow accumulation can look far too high for sleet accumulation such as that over GA and SC last week, so users are advised to think of them in terms of water equivalent. Since RAP and HRRR forecast snow density fields also, we will look into adding in the future a new experimental snow/sleet-accumulation-with-density-used field. Stan B.

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