Transcript NDFD.ppt

By John Metz
Warning Coordination Meteorologist
WFO Corpus Christi
NDFD in a nutshell
from teletype text…
…to digital data streams
Why NDFD?
• NWS forecasts must keep pace with the digital age.
There is still demand for NWS forecasts in text format.
• NWS has implemented the Interactive Forecast
Preparation System (IFPS) which allows forecasters to
create the forecast entirely in digital format.
• The digital database is made available to the public
through the NDFD website.
• Traditional text forecasts now fall out of the digital
database.
IFPS Grid Editor
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
Current NDFD
experimental elements
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Daytime maximum and nighttime minimum temperature
Probability of Precipitation (12 hour)
Significant weather
Sky cover
Temperature
Dewpoint temperature
Wind direction and speed
Precipitation amount (QPF)
Snow amount
Wave height
Elements shaded in Yellow = Official
NDFD Resolution
• Spatial resolution:
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- 5 km grids for now
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- 2.5 km grids when AWIPS hardware allows
• Temporal resolution:
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- 3 hourly for days 1-3
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- 6 hourly for days 4-7
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- as available from CPC beyond day 7
• Update frequency: every hour
Temperatures
Chance of Rain
Precipitation Amount
Weather Type
Cloud Cover
Wind Speed & Direction
NDFD elements under
development
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Apparent temperature (Heat index + wind chill)
Relative humidity
Floating PoP12 index (?)
Wind gust speed
Max/min relative humidity
Lightning Activity Level
Mixing height
Transport wind direction and speed
Haines index
Visibility
Ice coverage
Swell height and direction
NDFD Benefits
Provides weather information to “drive” custom
applications developed by private sector
• Decision support systems that fit the forecast to the problem
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- Weather information along a path
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- Text generation in more than one language
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- Forecasts for vehicles and hand-held devices with GPS
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- Controls for smart appliances (e.g., heating, cooling,
irrigation)
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- Graphics for mass media
Comparison
Traditional Text Forecast
New Digital Text Format
NDFD Data Flow
NCF
WFO
(120+)
Grids (Official Forecast)
AWIPS WAN
NDFD
Central
Server
NCEP
(6)
• Forecast grids are encoded in GRIB2 at WFOs and
NCEP
• Grids are decoded and stored to Informix RDBMS
• NDFD mosaics are generated hourly from WFO
grids
Timeliness of NDFD Data
NDFD Forecast Mosaics to 168 Hours (7 days)
Wed
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Day 8
At 1800 UTC every day, drop Day 1 and add new Day 7
Thu
Fri
Sat
Sun
Mon
Tue
Wed
Thu
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Day 8
NDFD Data Format
• Each file contains multiple GRIB2 bulletins for one
weather element
• Each GRIB2 bulletin begins with a unique WMO header
• Each GRIB2 bulletin contains data for a single weather
element for a single valid time
• Temporal resolution is 3 hours for Days 1-3 and 6 hours
for Days 4-7
• NDFD data issuance time (YYYYMMDDHH) is encoded
in each bulletin
NDFD Statistics Tracking
Several different types of statistics are tracked on the NDFD
(by WFO):
• Latest receipt times of WFO forecast
grids
• Average forecast update frequency :
- daily
- weekly
- monthly
NDFD Statistics Tracking
WFO Border Consistency Statistics
• Assists forecasters in tracking the
coordination their of gridded forecasts
• NDFD processes check (on an hourly
basis) the consistency of forecasts across
WFO boundaries for an average of
adjacent gridpoints
• Terrain effects are taken into account by
including average elevational differences
along WFO boundaries
• Image as well as tabular output is
produced as feedback to forecasters
NDFD Statistics Tracking
NDFD Forecast Verification
• Another source of feedback
to the forecaster to help
improve forecast quality
• Statistics are updated
monthly based on previous
month’s NDFD forecasts
• Tracks mean absolute error
and forecast bias
The End
[email protected]
361-299-1354
www.weather.gov
www.nws.noaa.gov/ndfd/