Corresponding author address: David P. Ruth,W/OSD25, Room 10410, SSMC2, NOAA, 1325 East-West Hwy., Silver Spring, MD 20910-3283; e-mail:David.Ruth@noaa.gov.Peter Wu is under contract to the Techniques Develop-ment Laboratory, National Weather Service.

Figure 1: Master menu for IFP.

8.8 INTERPRETATION AND EDITING TECHNIQUES FOR INTERACTIVE FORECAST PREPARATION

David P. Ruth , Mark A. Mathewson , Thomas J. LeFebvre , and Peter K. Wu1 2 3 4

Techniques Development Laboratory1 Advanced Development and2

Office of Systems Development Demonstration Laboratory National Weather Service, NOAA Office of Systems Development Silver Spring, Maryland National Weather Service, NOAA

Silver Spring, Maryland

Forecast Systems Laboratory3

Environmental Research Laboratories General Sciences Corporation4

Oceanic and Atmospheric Research, NOAA Laurel, Maryland Boulder, Colorado

1. INTRODUCTION

The National Weather Service (NWS) has beendeveloping and testing techniques that support InteractiveForecast Preparation (IFP) for more than a decade. Theconcept of IFP is key to achieving modernized forecastoperations at NWS field offices with the Advanced Wea-ther Interactive Processing System (AWIPS). With IFP,forecasters employ a family of techniques to prepareforecasts of weather elements from which many forecastproducts can be automatically composed and formatted.This family of IFP techniques is coordinated via a mastermenu (Fig. 1).

The Interactive Computer Worded Forecast (ICWF)system (Ruth and Peroutka 1993) has been used opera-tionally at several NWS offices since 1988. This systemwas developed by the Techniques Development Labora-tory (TDL) to support the generation of zone and station-oriented forecasts currently produced at WeatherForecast Offices (WFOs) nationwide. Interactive tech-niques provided in the ICWF enable the forecaster to viewand edit forecast elements at forecast locations (e.g.,counties, airports) and for time periods (e.g., tomorrow)that are specific to products in the current NWS productsuite.

With AWIPS, a much improved data stream isbeginning to flow to field offices. Forecasters at WFOsare able to view information from a variety of numericaland statistical forecast models at greater resolutions intime and space than ever before. With IFP, forecastersat AWIPS WFOs will apply their expertise by adding valueto high resolution model guidance. Thereby, a newgeneration of detailed grid-based products will becomeavailable to users of NWS forecasts (LeFebvre et al.1996).

Interactive grid editing techniques developed for theAWIPS Forecast Preparation System (AFPS) at theForecast Systems Laboratory (FSL) enable forecasters to

draw graphical depictions of predicted weather on spatialand time-series displays which are initialized from modelguidance, grids from national centers, or observations(Mathewson 1996). When working with grids, the fore-caster need not be preoccupied with geographic subdivi-sions where particular forecasts are issued, nor withparticular products and services. All the forecaster'sefforts can be dedicated to understanding and describingthe coming weather as an undivided phenomenon overthe entire forecast area.

Preparing a set of grids which completely describe allforecast elements at every hour can be a daunting task.Model interpretation techniques developed at TDL (Ruth1998) provide an alternative to drawing forecasts. Initially,the forecaster chooses a model or interactively blendsmodels which provide a reasonable first-guess forecast.The forecaster then adjusts slider bars which control the

Figure 2: Slider bar interface for model interpretation.

timing, location, type, and intensity of weather on grids.The resulting interpretation uses the original modelguidance to maintain spatial and temporal details whichare consistent with the adjusted forecast.

The NWS is currently consolidating the ICWF andAFPS into a single Interactive Forecast PreparationSystem (IFPS). This paper describes interactive tech-niques developed at both TDL and FSL which comprisethe consolidated system. These include interpretationand editing techniques to prepare forecast gridfields, aswell as interfaces to prepare zone and station forecasts;terminal aerodrome forecasts; and watches, warnings,and advisories. A companion paper in this volume(Peroutka et al. 1998) describes forecast products whichare generated via IFP.

2. THE IFPS MASTER MENU

The IFPS Master Menu (Fig. 1) coordinates theexecution of IFPS components. Via this menu, theforecaster initiates model interpretation techniques, gridediting, and interfaces specific to products for particularprogram areas. The forecaster can also control the flowof data between IFPS grid, zone, and point databases bysetting color-coded traffic signals.

With the ICWF, forecast preparation strategies varywidely from office to office. A common strategy has beenfirst to prepare key elements by modifying forecasts on

grids. These forecasts are then summarized for locationsand periods used in the public zone forecast. Similarzones are combined. The forecaster then employs thezone forecast matrix editor. Changes made with the zoneeditor can be "sprayed back" to the grids by applying deltafields. Forecasts for stations (e.g., Coded Cities Fore-casts) are either taken from the zone database or the griddatabase. Forecasts for other program areas (e.g.,aviation terminals) are extracted from the grids.

A different approach seems more appropriate inareas of diverse terrain. Forecasters in Boise, Idaho,prefer first to prepare station forecasts. Station forecastsare then used to initialize grids in concert with patterninformation from high-resolution numerical model guid-ance. Zone matrices are prepared last and are neverused to initialize station forecasts. 3. MODEL INTERPRETATION

IFPS model interpretation techniques enable fore-casters to adjust threshold values used in the initializationof categorical weather forecasts from model probabilities.Continuous fields are adjusted by defining significantcategories, adjusting category boundaries, and reinter-preting the original model field to fit that adjustment.Forecasters make these adjustments by moving sliderbars while viewing a color image of the resulting forecaston the screen (Fig. 2). Adjustments are made at selected

Figure 3: Graphical Forecast Editor.

forecast projections, interpolated in time, and then appliedto the original model fields at their full-resolution in timeand space. Model interpretation gains power and flexibil-ity by weighting slider adjustments according to terrainfeatures, related forecast elements, or forecast modelparameters. The fundamentals of model interpretationare described by Ruth and Du (1997).

4. GRID EDITING

Interactive grid modification tools were introducedinto the ICWF in 1993. These tools, described by Ruth(1993), enable forecasters to prepare forecasts for keyelements, primarily by adjusting the position of contourson the screen. Forecast grids are then computed fromcontours with the Systematic Interpolative Radial Search(Ruth 1992).

In the consolidated IFPS, the AFPS GraphicalForecast Editor (GFE) replaces ICWF grid modification.The GFE provides maps and graphs on which the fore-caster "draws" the weather for all forecast elements.Three interactive components are shown on the GFEscreen in Fig. 3. The grid manager, in the upper left,represents the forecaster's view of the grid database. Itis used to select a grid initialization from either modelguidance, observations, or the previous forecast. The

forecaster can also copy grid data, interpolate forecastsfor intermediate hours, or adjust a grid's valid times here.The spatial editor, on the right, presents the gridfield on aplanar surface. The temporal editor, in the lower left,presents a time-series for a single point or a collection ofgridpoints. These components are described in detail byLeFebvre (1995).

5. MATRIX EDITING

IFPS matrix editors (Fig. 4) enable forecasters to viewand edit information for the forecast elements, locations(points or zones), and time periods that are specific toNWS tabular and textual products. A single screenprovides coordinated spatial, temporal, station model,product text, and model guidance displays relevant to thematrix under the forecaster's cursor.

Digital Forecast Matrices (DFMs) are derived fromforecast grids. DFMs prepared in a matrix editor are useddirectly in IFP product formatters. Forecasters rely on thisinterface because the edits they make here have a wellunderstood influence on formatted products. The matrixeditor is also used to prepare DFMs for station, fireweather, marine, and NOAA Weather Radio forecastproducts within IFPS.

Figure 4: Matrix editor for public zones.

Figure 5: TAF time line editor.

6. TERMINAL EDITING

Because of their complexity, viewing and editingTerminal Aerodrome Forecasts (TAFs) graphically in IFPShas been a challenge (Oberfield and Ruth 1997).Figure 5 shows the TAF time line editor. Clouds, up tothree layers for each forecast group (i.e., prevailing,TEMPO, PROB40, PROB30), are plotted in a height-vs-

time plane. Station model plots of wind direction andspeed, obscuration, and visibility for each group aredrawn near the bottom of the screen. Precipitation, if any,is depicted as falling from the lowest cloud layer. Wea-ther is edited via pop-up menus which are invoked byclicking on an object on the screen.

7. WATCH/WARNING/ADVISORY INTERFACE

The graphical interface the forecaster uses to issuewatches, warnings, and advisories (WWA) is central toWFO operations. Storm information can be provided fromthe IFPS digital database (e.g., recommended WinterStorm Warning) and, in the future, from the System forConvective Analysis and Nowcasting (Smith et al. 1998).Recommended actions are graphically displayed alongwith all WWAs which are currently in effect. The fore-caster has the option to convert the recommendations toactual WWAs, issue new WWAs, cancel current WWAs,or clear portions of current WWAs. For most actions, theforecaster first specifies the hazard and then indicates theissuance area on the screen with the mouse. The AWIPSWWA graphical interface will be a combination of FSL'sWARNGEN program and the current ICWF WWA inter-face. Hazards are specified via the WWA composer(Fig. 6).

Figure 6: WWA composer.

8. CONCLUSION

IFPS provides an integrated array of interpretationand editing tools. The actual use of these tools dependson local forecast problems and preferences. IFP tech-niques are currently being prepared for implementationnationwide (Meiggs et al. 1998). As techniques forpreparing grid forecasts mature and grid-based forecastproducts become predominant within the NWS, it isexpected that forecasters will spend the majority of theirtime interpreting and editing gridfields. The continuedneed for specific editors in IFPS will largely depend onthe ability of IFPS to derive, from grid data alone, productspecific information including zone combinations, localeffects, and TAF sentences to the forecaster's satisfac-tion.

9. REFERENCES

LeFebvre, T. J., 1995: Operational forecasting withAFPS. Preprints 11th International Conference onInteractive Information and Processing Systems forMeteorology, Oceanography, and Hydrology, Dallas,Amer. Meteor. Soc., 294-254.

____, C. Bacco, and M. Romberg, 1996: Gridded fore-cast products and services under development atFSL. Preprints 15th Conference on Weather Analy-sis and Forecasting, Norfolk, Amer. Meteor. Soc.,473-476.

Mathewson, M. A., 1996: Using the AWIPS ForecastPreparation System (AFPS). Preprints 12th Interna-

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Meiggs, R. K., M. R. Peroutka, and D. P. Ruth, 1998:Implementing Interactive Forecast Preparationnationwide. Preprints 14th International Conferenceon Interactive Information and Processing Systemsfor Meteorology, Oceanography, and Hydrology,Phoenix, Amer. Meteor. Soc., elsewhere in thisvolume.

Oberfield, M. J., and D. P. Ruth, 1997: Preparing aviationterminal forecasts via the Interactive ComputerWorded Forecast. Preprints Seventh Conference onAviation, Range and Aerospace Meteorology, LongBeach, Amer. Meteor. Soc., J18-J21.

Peroutka, M. R., R. K. Meiggs, and M. B. Romberg, 1998:The generation of products in Interactive ForecastPreparation. Preprints 14th International Conferenceon Interactive Information and Processing Systemsfor Meteorology, Oceanography, and Hydrology,Phoenix, Amer. Meteor. Soc., elsewhere in thisvolume.

Ruth, D. P., 1992: The Systematic Interpolative RadialSearch (SIRS)--A method to compute gridpointvalues from contours. TDL Office Note 92-14,National Weather Service, NOAA, U.S. Departmentof Commerce, 16 pp.

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____, 1998: Model Interpretation using slider bars inInteractive Forecast Preparation. Preprints 14thInternational Conference on Interactive Informationand Processing Systems for Meteorology, Oceano-graphy, and Hydrology, Phoenix, Amer. Meteor. Soc.,elsewhere in this volume.

____, and M. R. Peroutka, 1993: The Interactive Com-puter Worded Forecast. Preprints Ninth InternationalConference on Interactive Information and Process-ing Systems for Meteorology, Oceanography, andHydrology, Anaheim, Amer. Meteor. Soc., 321-326.

____, and L. Du, 1997: Tailoring model forecasts withslider bars in the Interactive Computer WordedForecast. Preprints 13th International Conference onInteractive Information and Processing Systems forMeteorology, Oceanography, and Hydrology, LongBeach, Amer. Meteor. Soc., 124-127.

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