There are three basic goals for implementing The Tabular Product
Evolution in XML (TPEX) plan. The first is to modernize and improve
upon the current tabular product suite. The second is to streamline
and automate the generation of the future products. The third is
to maximize the role of the NDFD in the generation of the future
To meet these objectives, four new XML products have been designed.
Two Forecasts in XML (FoX) products, one Observations in XML (ObX),
and a Temperature Extremes in XML (TEX) will be generated. These
products can be used to generate the legacy SCS text product using
eXtensible Stylesheet Language Transformation (XSLT) style sheets.
In time, we expect users and partners to migrate away from the
legacy text products to the new XML products.
The two FoX products (FOX3 and FOX7)
will be generated hourly from the NDFD CSS, and contain forecasts
of weather and high/low temperatures for a select number of cities.
The first FoX product (FOX3) will contain forecasts for days 1
through 3. The FOX3 product will provide all the forecast data
for the same stations and times as in the current SCS and TAV products.
The second FoX product (FOX7) will contain forecasts for days 1
through 7. The FOX7 product provides considerably more information
than the legacy three day SCS/TAV products, and could be used as
a tool for advanced planning that is not available within the current
text product suite (SCS and TAV).
The FoX products have several improvements over their legacy tabular
counterparts (SCS/TAV/CCF). First, the FoX products will be issued
hourly. This increased frequency of issuance will allow for better
forecasts as synoptic weather conditions change throughout the
course of a given day. Second, there will be improvements to the
CoD parameter. The first improvement will be to add character of
the night values. The second improvement is to assign a more precise
set of weather definitions to CoD. The point-and-click codes will
be used as opposed to the old CCF CoD codes, as they contain both
daytime and nighttime values, whereas the CCF codes used in the
current legacy product suite only have daytime weather values.
The ObX product will be generated and issued hourly by the NCEP NCO. ObX will contain
observed maximum/minimum temperatures and observed precipitation
for the same cities as in the legacy SCS text product. At the appropriate
times of day, the ObX will also contain high and low temperatures “so
far today/tonight” in addition to the high and low temperatures
for the most recent complete day/night periods. This is one improvement
over the observational information contained in the current tabular
product suite. In addition, ObX will be issued hourly, providing
more accurate values for maximum and minimum temperature than the
current SCS product. For many western cities, overnight low and
daytime high temperatures reported in the legacy text SCS are not
credible since the issuance times are frequently before the temperature
has reached its maximum/minimum value. Hourly issuance of the ObX
product and the addition of the high/low so far today weather elements
will solve this problem.
The following observing period definitions have been created for
the ObX product. For maximum and minimum temperatures, the periods
have been defined as 7:00 a.m. to 7:00 p.m. and 7:00 p.m. to 8:00
a.m. Local Standard Time (LST) respectively. Precipitation observations
are defined as the last four 6-h synoptic times (cumulative). Maximum
Temperature “so far today” is defined as the period
between 7:00 a.m. to the current hour (not to exceed 6:59 p.m.).
Minimum Temperature “so far tonight” is defined as
the period between 7:00 p.m. to the current hour (not to exceed
7:59 a.m. the following day).
The TEX product will be generated and issued four times each day at the standard
synoptic times (0000, 0600, 1200, 1800 UTC) by the HPC. It will
contain the so-called National High/Low Temperatures observed in
the CONUS, using the same criteria currently used in the SCS. Due
to the flexibility of XML, the TEX could be readily expanded to
include extreme values for Outside CONUS (OCONUS) areas as well
(e. g., Alaska high and low).
The NDFD-generated SCS Product is designed to replicate the operational legacy SCS text product produced by the HydroMeteorological Prediction Center (HPC). The SCS product will be issued twice a day at approximately 0100 and 1300 Coordinated Universal Time (UTC). The SCS provides basic observations (Temperatures and Precipitation) for the previous day and 2-day forecasts of temperature and Character of Day (CoD) for 163 cities in the United States, Puerto Rico and the U.S. Virgin Islands. The NDFD-generated SCS will become the operational SCS on January 13, 2009 at 12 UTC.