You can access NDFD elements via file transfer protocol (ftp), http,
eXtensible Markup Language (XML), or web browser. Links to the data,
supporting information and software are listed below:
Currently, the NDFD contains data representing the following weather
elements. More elements will be added as development of the NDFD
progresses. NDFD data are available for projections (as described
in the table below) at the following Coordinated Universal Times
(UTC): 0000, 0300, 0600, 0900, 1200, 1500, 1800, 2100.
Elements |
No. of Grids |
Projections |
12-hour Probability of Precipitation (PoP12) |
13-15 |
Every 12 hours, out to 168 hours |
Apparent Temperature |
33-41 |
Every 3 hours out to 72 hours;
every 6 hours out to 168 hours |
Dew Point |
33-41 |
Every 3 hours out to 72 hours;
every 6 hours out to 168 hours |
| Hazards |
59-82 |
Every hour, out to 72 hours;
every 6 hours out to 120 hours |
Maximum Temperature |
7-8 |
Every 24 hours, out to 168 hours |
Minimum Temperature |
6-7 |
Every 24 hours, out to 168 hours |
Quantitative Precipitation Amount |
9-13 |
Every 6 hours out to 72 hours |
Relative Humidity |
33-41 |
Every 3 hours out to 72 hours;
every 6 hours out to 168 hours |
Significant Wave Height |
17-21 |
Every 6 hours out to 120 hours |
Sky Cover |
33-41 |
Every 3 hours out to 72 hours;
every 6 hours out to 168 hours |
Snow Amount |
5-9 |
Every 6 hours out to 48 hours |
Temperature |
33-41 |
Every 3 hours out to 72 hours;
every 6 hours out to 168 hours |
Weather |
33-41 |
Every 3 hours out to 72 hours;
every 6 hours out to 168 hours |
Wind Direction |
33-41 |
Every 3 hours out to 72 hours;
every 6 hours out to 168 hours |
Wind Gust |
17-25 |
Every 3 hours out to 72 hours |
Wind Speed |
33-41 |
Every 3 hours out to 72 hours;
every 6 hours out to 168 hours |
Climate Outlook Probabilities
- 12 separate elements: |
8- to 14-day Avg Temperature Above Normal |
1 |
14 days (issued once daily) |
8- to 14-day Avg Temperature Below Normal |
1 |
14 days (issued once daily) |
8- to 14-day Total Precipitation Above Median |
1 |
14 days (issued once daily) |
8- to 14-day Total Precipitation Below Median |
1 |
14 days (issued once daily) |
One-month Avg Temperature Above Normal |
1 |
45 days (issued
twice on 3rd Thurs of month) |
One-month Avg Temperature Below Normal |
1 |
45 days (issued twice 3rd Thurs each month) |
One-month Total Precipitation Above Median |
1 |
45 days (issued twice 3rd Thurs each month) |
One-month Total Precipitation Below Median |
1 |
45 days (issued twice 3rd Thurs each month) |
Three-month Avg Temperature Above Normal |
13* |
375 days (issued twice 3rd Thurs each month) |
Three-month Avg Temperature Below Normal |
13* |
375 days (issued twice 3rd Thurs each month) |
Three-month Total Precipitation Above Median |
13* |
375 days (issued twice 3rd Thurs each month) |
| Three-month Total Precipitation Below
Median |
13* |
375 days (issued twice 3rd Thurs each month) |
Convective Outlook Hazard Probabilities
- 9 separate elements: |
Convective Hazard Outlook |
3 |
Days 1, 2, and 3 |
Probability of Tornadoes |
1 |
Day 1 |
Probability of Hail |
1 |
Day 1 |
Probability of Damaging Thunderstorm Winds |
1 |
Day 1 |
Probability of Extreme Tornadoes |
1 |
Day 1 |
Probability of Extreme Hail |
1 |
Day 1 |
Probability of Extreme Thunderstorm Winds |
1 |
Day 1 |
Total Probability of Severe Thunderstorms |
2 |
Days 2 and 3 |
Total Probability of Extreme Severe Thunderstorms |
2 |
Days 2 and 3 |
Probabilistic Tropical Cyclone
Surface Wind Speeds - 6 separate elements: |
>34kts (incremental) |
17-21 |
Every 6 hours out to 120 hours |
>34kts (cumulative) |
17-21 |
Every 6 hours out to 120 hours |
>50kts (incremental) |
17-21 |
Every 6 hours out to 120 hours |
>50kts (cumulative) |
17-21 |
Every 6 hours out to 120 hours |
>64kts (incremental) |
17-21 |
Every 6 hours out to 120 hours |
>64kts (cumulative) |
17-21 |
Every 6 hours out to 120 hours |
* 13 issuances for months 1 - 3,
months 2 - 4, months 3 - 5, ..., up to months 13 -15 |
The elements in NDFD are available for the CONUS and 16
pre-defined CONUS subsectors. A subset of NDFD elements is
available for Puerto Rico/the Virgin Islands, Hawaii, Guam,
and Alaska. Refer to the NDFD
Element Status Table for the specific elements available for
each domain.
Grids for the CONUS are currently available from NDFD at 5 kilometer
spatial resolution. The spatial resolution for the grids for Hawaii and Guam
is 2.5 kilometers; for Puerto Rico/the Virgin Islands is
1.25 kilometers; for Alaska, 6 kilometers. For the North
Pacific Ocean Domain the spatial resolution is 10 km.
These spatial resolutions are nominal; the actual spacing in kilometers
varies by latitude.
The exact specifications for NDFD can be found in the GRIB2
Encoding Details for the National Digital Forecast Database and the NDFD
Spatial Reference System web page.
The temporal resolution of NDFD grids varies by element; see the
table of NDFD elements for specifics.
NWS plans to increase both spatial and temporal resolution in the future.
For real-time customer support, contact the NWS Telecommunications
Gateway at 301-713-0902
www.nws.noaa.gov