NDFDClimate: A Computer NDFDClimate: A Computer Application for theApplication for the

National Digital Forecast National Digital Forecast DatabaseDatabase

Christopher MelloChristopher MelloWFO ClevelandWFO Cleveland

NDFDClimateNDFDClimate NDFDClimate is a computer application that creates NDFDClimate is a computer application that creates

images of forecast and climatological parameters images of forecast and climatological parameters for the U.S. from two different digital data sets.for the U.S. from two different digital data sets. NDFD (National Digital Forecast Database) NDFD (National Digital Forecast Database)

weather forecast grids produced by the NWS and weather forecast grids produced by the NWS and PRISM data (Parameter-elevation Regressions on PRISM data (Parameter-elevation Regressions on Independent Slopes Model), an expert system Independent Slopes Model), an expert system that uses point climatological temperature data that uses point climatological temperature data and a digital elevation model (DEM) to generate and a digital elevation model (DEM) to generate gridded estimates of climate parameters.gridded estimates of climate parameters.

PRISM DataPRISM DataParameter-elevation Regressions on Independent Slopes Parameter-elevation Regressions on Independent Slopes

ModelModel

PRISM system determines climate elements PRISM system determines climate elements (temp, or rainfall) values at grid cells by (temp, or rainfall) values at grid cells by calculating linear regression relationships calculating linear regression relationships between the climate element and elevationbetween the climate element and elevation

Each grid cell estimate is determined from a Each grid cell estimate is determined from a separate multiple linear regression using data separate multiple linear regression using data from nearby climate stationsfrom nearby climate stations

Each station in the regression is weighted Each station in the regression is weighted based on five factors: distance, elevation, based on five factors: distance, elevation, vertical layer (helps identify temp inversions in vertical layer (helps identify temp inversions in high mountain valleys), topographic orientation, high mountain valleys), topographic orientation, coastal proximitycoastal proximity

PRISM DataPRISM DataParameter-elevation Regressions on Independent Slopes Parameter-elevation Regressions on Independent Slopes

ModelModel

Temperature data from PRISM consist of Temperature data from PRISM consist of daily maximum and minimum temp daily maximum and minimum temp fields for 1971 – 2000 at 5 km resolutionfields for 1971 – 2000 at 5 km resolution

PRISM derived daily normal max & min PRISM derived daily normal max & min temperature grids were compared to temperature grids were compared to official data from the NCDC for CLE, official data from the NCDC for CLE, TOL, ERI, YNG, SYR, RIC, & GSPTOL, ERI, YNG, SYR, RIC, & GSP

Each site had a MAE near 0.25Each site had a MAE near 0.25°° F for F for both max and min temp with the both max and min temp with the highest daily error < 1highest daily error < 1°° F F

NDFD DataNDFD DataNational Digital Forecast DatabaseNational Digital Forecast Database

NDFD consists of digital forecast data NDFD consists of digital forecast data that are produced by the WFOs across that are produced by the WFOs across the U.S. and merged into a single image the U.S. and merged into a single image or file for each parameter and projection.or file for each parameter and projection.

Forecast grids are produced for Days 1-7 Forecast grids are produced for Days 1-7 with 5 km resolutionwith 5 km resolution

NDFD grids include max and min temp, NDFD grids include max and min temp, POP, temp, water equivalent, snow POP, temp, water equivalent, snow amountamount

NDFDClimateNDFDClimate NDFDClimate uses the GRADS software NDFDClimate uses the GRADS software

to create images that utilize to create images that utilize information from both the NDFD and information from both the NDFD and PRISM dataPRISM data

GRADS has the ability to add, subtract, GRADS has the ability to add, subtract, or manipulate fields using many or manipulate fields using many formulas. Users can specify the formulas. Users can specify the domain and contour interval of images.domain and contour interval of images.

NDFDClimateNDFDClimate NDFDClimate produces NDFDClimate produces

temperature anomaly grids by temperature anomaly grids by subtracting NDFD grids from PRISM subtracting NDFD grids from PRISM derived daily climate gridsderived daily climate grids

NDFDClimate combines some NDFDClimate combines some NDFD fields to generate 5 day NDFD fields to generate 5 day totals of heating and cooling totals of heating and cooling degree days and 60 hour QPFdegree days and 60 hour QPF

NDFD Low Temp Fcst

Normal Low Temp 0909

Min Temp Anomaly 0909

Max Temp Anomaly

NDFD 5day Total CDD °F

NDFDClimate UsesNDFDClimate Uses

Processes NDFD data for users Processes NDFD data for users with 5 day HDD & CDD totals with 5 day HDD & CDD totals temp changestemp changes

Educate users on current Educate users on current temperatures anomalies where temperatures anomalies where point data may be inadequatepoint data may be inadequate

NDFDClimateNDFDClimate ReferencesReferences

Berman, F., A. Chien, K. Cooper, J. Dogarra, I. Foster, D. Berman, F., A. Chien, K. Cooper, J. Dogarra, I. Foster, D. Gannon, L. Johnson, K. Kennedy, C. Kesselman, J. Mellor-Gannon, L. Johnson, K. Kennedy, C. Kesselman, J. Mellor-Crummey, D. Reed, L. Torczon, and R. Wolski., 2002. The Crummey, D. Reed, L. Torczon, and R. Wolski., 2002. The GRADS Project: Software Support for High-Level Grid GRADS Project: Software Support for High-Level Grid Application Development. Application Development. International Journal of High International Journal of High Performance Computing ApplicationsPerformance Computing Applications, , 1515 327-344. 327-344.

Daly, C., R.P. Neilson, and D. L. Phillips, 1994. A Statistical-Daly, C., R.P. Neilson, and D. L. Phillips, 1994. A Statistical-Topographic Model for Mapping Climatological Precipitation Topographic Model for Mapping Climatological Precipitation over Mountainous Terrain. over Mountainous Terrain. J. Appl. MeteorJ. Appl. Meteor., ., 3333, 140-158, 140-158