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Research to Operations Activities

Testbed Activities




Annual Flash Flood and Intense Rainfall Experiment (FFaIR)


In collaboration with the atmospheric and hydrologic forecasting and research communities,the WPC-HMT conducts an annual Flash Flood and Intense Rainfall Experiment for four weeks during the warm-season summer months. This experiment focuses on improving short term quantitative precipitation (QPF) and flash flood forecasts through the use of high resolution models and ensembles and rapidly updating hydrologic information.



Annual Winter Weather Experiment (WWE)


In an effort to support improvements in winter weather forecasts, the Hydrometeorology Testbed at WPC (HMT-WPC) began hosting an annual winter weather experiment in 2011. These experiments bring together members of the operational forecasting, research, and academic communities to address winter weather forecast challenges. Previous experiments have focused on exploring the utility of high-resolution models, model implicit snowfall forecasting techniques to improve both deterministic and probabilistic snow and ice forecasts in the Day 1-7 time frame.



The Extended Range Forecast Experiment (ERFE)


In the Extended Range Forecast Experiment (ERFE), WPC-HMT scientists evaluate numerous probabilistic and ensemble based guidance tools, for a variety of sensisble weather elements, and collaborate with WPC Hazardous Weather Forecasters with the aim of better indentifying hazardous and impacting weather in the Days 3-7 period. Since June 2020, the ERFE Hazards sessions have been an in-house effort featuring the testing and evaluation of assorted tools, along with a one on one training component with WPC Hazards Forecasters in a real time environment. This is a year round, all seasons effort which explores numerous anomalous weather situations over the U.S. Cluster analysis tools derived from 500 hPa EOF analysis as well as QPF clusters whose principal components are derived from regional bias corrected and downscaled QPF are evaluated in the experiment sessions. Exploring hazardous weather scenarios featuring multiple anomalous sensisble weather elements using probabilisitc guidance and depiction is a critical interest of ERFE.



The Day 8-10 Experiment


The Day 8-10 component of the Extended Range Forecast Experiment (ERFE) was initially a NGGP project to establish a baseline skill at Days 8-10 for existing operational datasets, assess the skill and utility of experimental guidance, and the skill of daily forecasts in the Day 8-10 period. New and experimental versions of NCEP guidance were evaluated, and new Day 8-10 forecast products were developed highlighting high-impact hazardous events. From January 2017 through February 2020, the Day 8-10 Experiment was conducted remotely year round with partners from the academic research community, the Climate Prediction Center (CPC), and the Environmental Modeling Center (EMC). Since March 2020, the daily forecast component of the experiment has been automated, with the prototype forecasts available here. The participant focus has shifted to identification of impactfull weather hazards using WPC developed cluster analysis for Days 8-10 and the North Pacifc Jet (NPJ) canonical tool. Both the GFS and ECMWF ensemble systems are evaluated using the NPJ tool.



Object-Oriented Verification

In collaboration with NOAA-HMT and the Developmental Testbed Center (DTC), HMT-WPC is exploring the use of object-oriented verification. The goal of this type of verification is to better account for spatial discontinuities between the forecast and observed precipitation. HMT-WPC is using the Method for Object-Based Diagnostic Evaluation (MODE) tool for the verification of model and WPC forecaster QPF. The MODE tool is part of the Model Evaluation Tools (MET) verification package developed by DTC. This verification is available to view here.

Past Activities




Rossby Wave Packet Tool for Medium Range Forecasting (CSTAR)


A Rossby Wave Packet Tool is being tested by WPC medium range forecasters during the 2012-13 cold season. Rossby Wave Packets are a quantitative way to depict the group velocity of a train of multiple troughs and ridges, and their propagation. The development of the tool is the result of a CSTAR funded collaborative effort between WPC and Stony Brook University. Extreme weather events have been found to be associated with wave packets, and one of the main goals of this work is to identify and forecast wave packet episodes using output from multiple global models. Introductory training was provided to HPC forecasters in August 2011.



Model Displacement Biases (COMET Partners)


HPC collaborated with researchers from Texas A&M University as part of a COMET Partners project that focused on determining whether operational numerical weather prediction (NWP) models have a consistent displacement bias in the predicted location of elevated warm season convective systems. Using the Method for Object-Based Diagnostic Evaluation (MODE) tool, Texas A&M researchers objectively confirmed forecasters' subjective impression that there is a north bias in the location of elevated convection systems in both the NAM and the GFS. A report detailing the project's findings can be found here.  



Probabilistic QPF


WPC is experimenting with probabilisitc QPF products. The products consist of both the probability of exceeding a given precipitation threshold as well as precipitation amounts by percentile. The products are generated automatically using the WPC deterministic QPF and uncertainty information from an ensemble. A binormal probability distribution (density) function (PDF), which allows skewness, is constructed such that the mode is the WPC QPF and the variance is that of the ensemble. The skewness is based on the position of the WPC QPF in the ensemble distribution. This approach to estimating the three parameters for the binormal PDF is a variation on the method of moments. Here is a realtime depiction of probabilisitc QPF.  



Predecessor Rainfall Events


HMT-WPC is investigating the diagnosis and identification of predecessor rainfall events (PREs). A comparison of model performance between the NAM and the GFS as well as an evaluation of WPC QPF is being looked at to help improve WPC QPF forecasts. The application of a meridional moisture flux tool is being investigated to identify transport of deep tropical moisture into the mid-latitude heavy rainfall system. 






Snow/Ice Accumulation Tool


HMT-WPC collaborated with EMC cloud physicist Brad Ferrier to develop an algorithm to estimate hourly snowfall accumulation. The algorithm utilizes a parameter in the Ferrier microphysics scheme called the "rime factor" to estimate one-hour instantaneous snow/ice accumulation from NCEP's NAM 12km model. This data was made available to WPC forecasters in NAWIPS. (Fall 2009)


Training was provided to WPC Forecasters during November 2009.


In November 2012, an updated algorithm was delivered to NAWIPS. The update used the rime-facter data from the NAM12 to modify the Roebber Snow to Liquid Ratio (SLR) computed for the NAM. This modified SLR was then multiplied by the percent of frozen precipitation output from the NAM12, and the NAM12 post processed precipitation to arrive at a snow accumulation forecast. This data set was tested in the 2013 Winter Weather Experiment.

and implemented into WPC winter weather operations in February 2013.



WPC Heavy Rainfall Forecasting Manual


Wes Junker developed a forecasting manual for forecasters preparing QPFs. This training material is available online and contains a wealth of information on warm season precipitation forecasting. (Summer 2008)



Whitaker-Hamill Reforecast Technique


The HMT-WPC evaluated the Whitaker-Hamill reforecast technique and migrated it to NCEP computers. This data is now available for WPC forecasters in NAWIPS to aid in precipitation forecasting. (Winter 2006-2007)



Normalized Anomalies


The use of normalized anomalies has been successfully migrated into WPC operations. Model forecasts of normalized anomalies for both mass fields and mositure diagnostics (precipitable water and moisture flux) are available both in NAWIPS and online. (Winter 2005-2006)

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Page last modified: Tuesday, 29-Jun-2021 18:04:07 UTC