1. Realities (NDFD, NDGD, IFPS)
David Ruth
Meteorological Development Laboratory
National Weather Service, NOAA
3rd NCEP/NWS Ensemble User Workshop
November 1, 2006

2. The National Academies - 2003

3. National Digital Forecast Database (NDFD)
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

4. How is NDFD Produced? Detailed Interactive Collaborative
National Centers Model Guidance
Detailed
Interactive
Collaborative
Grids
Local Digital Forecast Database
Field Offices
National Centers
Collaborate
Data and Science Focus
NWS Automated Products
User-Generated Products
National Digital Forecast Database
TODAY...RAIN LIKELY. SNOW LIKELY ABOVE 2500 FEET. SNOW ACCUMULATION BY LATE AFTERNOON 1 TO 2 INCHES ABOVE 2500 FEET. COLDER WITH HIGHS 35 TO 40. SOUTHEAST WIND 5 TO 10 MPH SHIFTING TO THE SOUTHWESTEARLY THIS AFTERNOON. CHANCE OF PRECIPITATION 70%.
Digital
Text
Graphic
Voice

5. Spatial Detail Evident in the NDFD

6. Availability of NDFD Grids via FTP XML web service
WMO GRIB v2 format
CONUS, 16 CONUS sectors, Hawaii, Guam, and Puerto Rico
GIS output available via downloadable GRIB decoder
XML web service
NDFD points in Extensible Markup Language (XML)
Element, forecast time, and point location requested by user application
Access via Simple Object Access Protocol
Web graphics at weather.gov/forecasts/graphical

7. Who downloads NDFD grids?
M2M User

8. Commercial NDFD graphics
The Weather Underground

9. Commercial NDFD graphics
Ham Weather

10. Commercial NDFD graphics
AccuWeather Pro (by subscription)

11. NDFD in commercial software
WeatherBug Plus ($19.95)

12. NDFD GIS display
ESRI ArcMap-ArcInfo

13. NDFD point forecast via Google Maps
Weather Mole

14. NDFD point forecast via Google Maps
Weather Bonk

15. Route Forecast from NDFD
Weather Bonk

16. Interactive NDFD Airport Forecasts
Weather Meister

17. Observed Weather at 3/22 00z

18. 7 days of forecasts valid 3/22 00z

19. NDFD Forecast Elements - original dozen -
Status
Probabilistic
Range
Source
Maximum Temperature
operational no
7 days
WFO
Minimum Temperature
PoP12
yes
Hourly Temperature
Hourly Dewpoint
Predominant Weather
Wind Direction
Wind Speed
Sky Cover
experimental
Precipitation Amount
3 days
Snow Amount
2 days
Significant Wave Height
5 days

20. NDFD Forecast Elements - latest additions -
Status
Probabilistic
Range
Source
Apparent Temperature
operational no
7 days
WFO
Relative Humidity
Trop. Cyclone Winds >34kt
experimental
yes
5 days
TPC
Trop. Cyclone Winds >50kt
Trop. Cyclone Winds >64kt
Wind Gust

21. NDFD Forecast Elements - contribution from SPC -
Status
Probabilistic
Range
Source
Tornadoes
planned
yes
1 day
SPC
Hail
Damaging Tstorm Winds
Extreme Tornadoes
Extreme Hail
Extreme Tstorm Winds
Total Severe Tstorm
3 days
Total Extreme Tstorm

22. NDFD Forecast Elements - contribution from CPC -
Status
Probabilistic
Range
Source
Temp. Above Normal
planned
yes
8-14 day
CPC
Temp. Below Normal
Precip Above Normal
Precip Below Normal
30 day
90 day

23. NDFD Forecast Elements - proposed and deferred -
Status
Probabilistic
Range
Source
Prob. of Frozen Precip
deferred
yes
7 days
WFO
Prob. of Freezing Precip
Prob. of Thunderstorms
Probabilistic QPF
3 days
Floating PoPs
PoP06

24. NDFD Forecast Elements - next in line from WFOs -
Status
Probabilistic
Range
Source
Weather Hazards
2007 no
TBD
WFO
20 ft Winds
Max/min Relative Humidity
Lightning Activity Level
Mixing Height
Transport Winds
Haines Index
Ceiling Height
Visibility
Ice Coverage
Swell Height
Swell Direction

25. The Digital Forecast Process
Numerical
Modeling
Observations
Output
Model
Interpret.
Sensible
Weather
Forecast
Editing
Digital
Product
Generation
User
Products

26. Interactive Forecast Preparation
4D Field
Modification
Matrix
Editing
Observations
Threshold
Adjustment
Numerical
Modeling
Object
Editing
Grid
Editing
Model
Interpret.
Numerical
Output
Forecast
Editing
Sensible
Weather
Product
Generation
Digital
Forecast
User
Products

27. Proposed Course of Action 2003 MDL Science Review
Phase out software as an external MDL product line
Establish MDL as world leader in the Probabilistic Real-time Interpretation of Models and Forecasts
Make MDL interpretative products available in database that provides interoperability with NDFD

28. PRIMF Digital Flow Climatology PRIMF Server Current Observation
Numerical
Output
NDGD
NDFD
NWS Forecast Offices
and Centers
NWS Customers
and Partners

29. PRIMF Components High-resolution MOS and updates to MOS (i.e., LAMP)
Statistical interpretation of NDFD highlighting forecast uncertainty (NUANCE)
Real-time forecast monitoring and feedback
Probabilistic coastal hazards
Verification of NDFD and NDGD

30. NUANCE NUANCE = Numerical Uncertainty Assessment of
NDFD via Climatology and Ensembles
Given the single value NDFD forecast for a weather element,
recent NDFD performance,
and related guidance (e.g., ensemble spread),
quantify the expected variability of observations for that weather element.

31. Personal Views on Reality
Forecasters at 120+ WFOs neither have the time, expertise, or tools to quantify uncertainty for all NDFD elements.
Information about forecast uncertainty can be derived from NDFD single value forecasts, climatology, and ensemble spread.
NDFD and NDGD provide an ideal avenue to convey uncertainty information to those who can use it in digital form.
Complex decision support applications and displays should be developed by private weather providers for specific user communities.
Uncertainty information can be added to NWS end-user products created from NDFD and NDGD