precipitation forecast precipitation forecast abbreviated expected melted precipitation accumulated specified time period specified area created precipitation amounts reaching minimum threshold expected forecast valid period valid periods precipitation forecasts normally hours terrain considered use topography based precipitation patterns observations fine detail starting mid late 1990s forecast models simulate impact rivers united_states forecast models significant sensitivity humidity levels boundary layer lowest levels atmosphere decreases height generated amounts probability specific basis radar imagery techniques higher skill model forecasts hours time radar image forecasts verified use rain gauge measurements weather radar estimates combination skill scores determined measure value rainfall forecast use radar exist forecast rainfall based short term radar trends matter hours radar imagery techniques higher skill model forecasts hours time radar image use forecast models past responsible generating entire weather forecast based available observations today input generally confined choosing model based parameters model performance consensus forecast models ensemble members models help reduce forecast error regardless small average error individual system large errors particularly piece guidance possible given model run professionals required interpret model data weather forecasts lay person professionals use knowledge local effects small size resolved model add information forecast example terrain considered process topography precipitation patterns observations fine detail model guidance comparing forecast fields extreme events excessive precipitation associated later flood events lead better forecasts increasing accuracy forecast models implies humans longer needed forecast process point future currently need human intervention precipitation hours referred time range possible forecast smaller features individual showers thunderstorms reasonable accuracy features small resolved computer model human given latest radar satellite data able better analysis small scale features present able accurate forecast following hours expert systems data numerical model better including evolution features time ensemble detail given forecast decreases time errors increase point errors large forecast actual state atmosphere looking single forecast model gives indication likely forecast correct ensemble production forecasts order reflect uncertainty initial state atmosphere errors observations insufficient sampling uncertainty forecast assessed range different forecasts produced ensemble forecasts increasingly operational weather example european centre medium range weather forecasts canadian center ensemble mean forecasts precipitation problems associated use fields average extreme values limited extreme events case ensemble mean united_states decreasing starts values low inches probability approach addition graphical rainfall forecasts showing amounts rainfall forecasts describing certain rainfall amounts met allows assign degree uncertainty forecast technique considered relative method years national_weather_service forecasts period chance rain equals chance inches fall particular spot case known probability precipitation derived forecast computer post processing entities generate rainfall forecasts australia began method rainfall combination ensemble different forecast models termed poor man ensemble forecasts accurate time individual models composing ensemble quick produce available water land page website hong_kong generates short term warnings systems expected accumulate certain rainfall hour hours use levels warning amber warning indicates rainfall intensity millimetres hour expected red warning indicates rainfall amounts millimetres hour anticipated black warning indicates rainfall rates millimetres possible united_states united_states local forecast offices national_weather_service create precipitation forecasts days future amounts equal greater inches starting mid late 1990s forecast models simulate impact rainfall river stages rainfall forecasts verified number ways rain gauge observations averages compared forecast models weather radar estimates outright corrected rain gauge observations statistical scores based observed forecast fields known bias compares size forecast field observed field goal score threat score involves intersection forecast observed sets maximum possible score probability detection pod found dividing overlap forecast observed fields size observed field goal score critical success index csi divides overlap forecast observed fields combined size forecast observed fields goal score false alarm rate far divides area forecast overlap observed field size area goal value measure zero tropical cyclones impact united_states global forecast model performed best regards rainfall forecasts years forecast models
Quantitative precipitation forecast