NOAAs National Weather Service Forecasting by the Numbers: The National Weather Service Goes Digital

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NOAAsNational Weather ServiceForecasting by
the Numbers The National Weather Service Goes
Digital

• Tim BoyerNOAA/NWS/Meteorological Development
  LaboratoryNOAA WebShop 2004
• July 28, 2004

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The Forecast Generation Process

• Until recently Official NWS public forecasts were
  created manually by typing products at each
  Weather Forecast Office (WFO)

.TONIGHT...CLEAR. LOW IN THE MID 30S. LIGHT WIND
EARLY BECOMING SOUTHWEST 10 TO 15 MPH AFTER
MIDNIGHT. .SUNDAY...MOSTLY SUNNY AND WARMER.
HIGH IN THE UPPER 60s. SOUTHWEST WIND 15 TO 25
MPH BECOMING NORTH DURING THE AFTERNOON. .SUNDAY
NIGHT...CLEAR. LOW AROUND 30. LIGHT
WIND. .MONDAY...SUNNY AND COOLER. HIGH IN THE
MID 50S.
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Interactive Forecast Preparation System (IFPS)

• A 7-day digital forecast database is established
  at each WFO
• Forecasters interactively modify the contents of
  the database according to the latest observations
  and model guidance
• NWS text, tabular, voice, and graphical products
  are generated from the database
• The database itself is provided as an NWS product
  to customers and partners

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IFPS Grid Editor
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Benefits to Interactive Forecast Preparation

• Maximizes human contribution to forecast process
• Provides more forecast detail in time and space
• Enables more effective communication with users
  (e.g., graphics)
• Increases the usefulness of NWS forecasts to
  customers and partners

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A National Digital Forecast Database
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NDFD Definition

• Contains a seamless mosaic of NWS digital
  forecasts
• Is available to all users and partners public
  and private
• Allows users and partners to create wide range of
  text, graphic, and image products

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NDFD Benefits

• Provides weather information to drive custom
  applications developed by private sector
• - Decision support systems that fit the forecast
  to the problem
• - Weather information along a path
• - Text generation in more than one language
• - Forecasts for vehicles and hand-held devices
  with GPS
• - Controls for smart appliances (e.g., heating,
  cooling, irrigation)
• Graphics for mass media
• Geographic Information Systems

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NDFD Data Flow
and High-Level System Architecture
AWIPS Network Control Facility (NCF)
NDFD Stage Develop
NDFD Central Server (backup)
NDFD Central Server (primary)
Grib2
AWIPS WAN
NCF LAN
NWS Telecommunications Gateway (NWSTG)
Grib2
NWS Web Farm
NCEP/NC (6)
Web Server HTTP SOAP Services
FTP Server Products
Grib2
Imagery/ XML
NCDC
FTP
Internet
Grib2
Partners Customers
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NDFD Central Server
Creating/updating CONUS/OCONUS mosaics
Every HOUR

• Process launches to add the latest WFO
• grids to the NDFD mosaics
• Masks are used to map WFO grids to
• the national map
• Masks are continuously updated for
• changes in CWA definitions and areas
• of responsibility for different elements
• New/updated mosaics are stored to
• RDBMS for image generation, consistency
  checking, etc

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Creating NDFD Mosaics

• Only those grids which have been
• updated in the past hour are added to
• the mosaics
• Critical for WFO grid domains to be
• defined such that they coincide with
• NDFD 5km mesh (but can be at higher
• resolution)
• Provide feedback on forecast
• consistency to WFOs

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NDFD forecast elements

• The NDFD will contain
• Weather, water, and climate forecasts from WFOs,
  RFCs, and NCEP Service Centers
• Elements that support generation of current WFO
  products
• Digital watch, warning, and advisory information
• Elements that would attract user development of
  graphics and decision tools
• The official NWS forecast for each element

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Current NDFD experimental elements

• Daytime maximum and nighttime minimum temperature
• Probability of Precipitation (12 hour)
• Predominant weather
• Sky cover
• Temperature
• Dewpoint temperature
• Wind direction and speed
• Precipitation amount (QPF)
• Snow amount
• Wave height

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NDFD elements under development

• Apparent temperature (Heat index wind chill)
• Relative humidity
• Floating PoP12 index (?)
• Wind gust speed
• Max/min relative humidity
• Winds at 20ft (Fire Weather)
• NCEP Service Center Products
• 8-14 day Temperature and Precipitation Outlook
• Monthly and Seasonal Temp/Precip Outlooks

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NDFD Products

• NDFD experimental products are divided into two
  broad categories
• National and Sectorized Mosaics
• The GRIB2-encoded NDFD mosaics available for FTP
  download at
• the NWSTG
• Sectorized data includes mosaics for Puerto Rico
  (Alaska, Hawaii, and
• Guam will be available in the future)
• Other products (HTTP-accessible at NWS Graphical
  Forecasts web page)
• Forecast images (http//www.nws.noaa.gov/forecas
  ts/graphical)
• XML products (http//www.nws.noaa.gov/forecasts/
  xml)

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Dissemination of NDFD Products

• The entire NDFD is updated at the NWSTG
• every hour
• Latest GRIB2 files can be found at
• HTTP
• http//weather.noaa.gov/pub/SL.us008001/St.expr/DF
  .gr2/DC.ndfd/
• FTP
• ftp//tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr
  2/DC.ndfd/
• Files are arranged in directories
• according to geographical region

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NDFD Products Format

• Each file contains multiple GRIB2 bulletins,
  each corresponding to a unique
• valid time for one weather element, generated
  at a single issuance time
• Each file contains a unique WMO superheader to
  identify the products within
• the file
• For a list of NDFD WMO super headers
• http//www.nws.noaa.gov/datamgmt/doc/ndfdelem.x
  ls
• Each projection is encoded in a GRIB2 bulletin,
  with a unique WMO header to
• identify the specific product
• NDFD data issuance time (YYYYMMDDHH) is encoded
  in each GRIB2 bulletin
• For more information on weather and encoding
  details of other NDFD
• elements, see http//www.nws.noaa.gov/datamgmt/d
  oc/GRIB2_encoding.html

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Obtaining NDFD Mosaic Products

• The NWS has provided NDFD users web client
  software to easily download
• and locally decode NDFD mosaic products from
  the NWSTG
• http//www.nws.noaa.gov/mdl/NDFD_GRIB2Decoder/
• Software can be installed on local system
  (Windows, Linux, UNIX).
• Provides a graphical user interface for
  specifying products to download and
• decode and image generation capability
• Currently in use by other NOAA offices (e.g.,
  Office of Coast Survey
• NOWCoast Web Portal)

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NDFD Access Tools
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NDFD GRIB2 Decoder Client (degrib)

• Software is constantly updated and maintained by
  the NWS
• Meteorological Development Laboratory
• Offers users an easy way to import NDFD data,
  via the web,
• into local applications
• For more details on the capabilities of the NDFD
  GRIB2
• decoding software, stay tuned to the next
  presentation
• Accessing the GRIB2 Encoded National Data
  Forecast Database