Using Local-Scale Time-Lagged Ensemble Visualization Tools to Extract Forecast Signals in Medium-Range Model Guidance (267)

Matthew Stalley, NWS - WFO Dallas/Fort Worth, Fort Worth, TX

Ted Ryan, NWS-WFO Dallas/Fort Worth

 

Abstract:

Using Local-Scale Time-Lagged Ensemble Visualization Tools to Extract Forecast Signals in Medium-Range Model Guidance

Matthew Stalley and Ted Ryan

NOAA/National Weather Service Fort Worth, Texas

The usefulness of stand-alone numerical model solutions through 14 days can be minimized due to a lack of run-to-run consistency and relatively poor verification statistics. However, a time-lagged ensemble approach allows forecasters to harvest meaningful signals from trends within a model. Evaluating many runs of a particular model at various valid times can be a daunting task. Thus, the challenge becomes how to best display such data to be viewed, interpreted, and analyzed. Following the framework of Carbin et al. 2016 who accomplished this task while utilizing the Climate Forecast System, version 2 (CFSv2) on a national scale, a similar tool was developed using the Global Forecast System (GFS) on a scale localized to a National Weather Service (NWS) County Warning Area (CWA).

In order to consolidate numerical model data such that approximately 1000 valid forecast time steps can be displayed simultaneously, a heat map design (commonly called a &ldquochiclet&rdquo chart) was implemented by plotting the model run time versus the forecast valid time. Each pixel, or &ldquochiclet&rdquo contains a domain-averaged meteorological parameter of interest, such as supercell composite parameter, fire weather threat parameter, or even temperature and precipitable water departure information with respect to the climatology of the domain. This CWA-centric data display structure immediately allows forecasters not only to assess model trends that may signal a wide array of potential threats and impacts, but also identify &ldquotargets of opportunity&rdquo throughout the forecast period where efforts should be focused to add detail and value to the forecast. These products are widely used among NWS Southern Region forecast offices and have enhanced Decision Support Service (DSS) capabilities through the medium-range portion of the forecast.