Evolving Guidance to Support NWS Field Operations (Invited Presentation)

Evolving Guidance to Support NWS Field Operations

David P. Ruth

Meteorological Development Laboratory

Office of Science and Technology Integration

National Weather Service, NOAA

Silver Spring, Maryland

For the past 50 years, the Meteorological Development Laboratory (MDL) [formerly the Techniques Development Laboratory (TDL)] of the National Weather Service (NWS) has been postprocessing Numerical Weather Prediction (NWP) output to support NWS field operations. This statistical guidance, along with software developed for forecasters to interactively modify it, has enabled the NWS to advance from providing general forecasts for large multi-county zones over 12-h and 24-h periods of time, to providing detailed forecasts on fine-resolution 2.5.km grids at up to 1-h resolution. In addition to increases in temporal and spatial forecast resolution, improvements to NWP and its post-processed guidance have enabled increases in operational NWS forecast accuracy so that day 2 forecasts in this decade are now about as good as day 1 forecasts were a decade earlier at the same observation sites. Furthermore, a full suite of MDL post-processed forecast guidance out to 10 days is now being updated hourly to pull in output from the latest runs of a large diversity of forecast models, rather than several times per day based on only a few models.

This presentation will highlight the use of MDL guidance to support the implementation of early experimental versions of Interactive Computer Worded Forecasts (ICWF) on Automation of Field Operations and Services (AFOS) computers, followed by the nationwide operational implementation of the Interactive Forecast Preparation System (IFPS) on the Advanced Weather Interactive Processing System (AWIPS) in support of the creation of a National Digital Forecast Database (NDFD). It will describe the adaptation of MDL guidance from station Model Output Statistics (MOS) interpolated to zone centers, to gridded MOS (GMOS) specially fit to NDFD grids, and culminating with today’s National Blend of Models (NBM). The NBM has been built to provide a nationally consistent and skillful suite of calibrated forecast guidance based on a blend of NWS and non-NWS deterministic, ensemble, and statistically post-processed model output which is suitable for use as a common starting point for NDFD. The presentation will include more than 50 years of verification results including comparative scores for MOS guidance, NBM, and operational NWS forecasts.