Frequently Asked Questions
What is the accuracy of the GWC forecast?
The forecast accuracy has been tested repeatedly over the last decade and routinely proves to be the best available forecast across a variety of comparison approaches. Specific accuracy results depend on a wide variety of considerations, including location, season, and variable being assessed. GWC has won "Most Accurate Forecast" for high temperature in 2013, 2014, and 2015 for U.S., Europe and Asia, according to ForecastWatch.
What forecasted variables are available?
See Specifications of Services for each individual GWC service.
What underlying numerical weather models are included?
Relevant models are included from the U.S. National Weather Service (NWS), the European Centre for Medium-Range Weather Forecasts (ECMWF), the UK Met Office, and Environment Canada. The particular models used depend on the region and the forecast time.
Do some regions have higher fidelity?
Yes. We currently use more model data (for SensorWX) and perform intermediate computations at higher spatial resolution (for PointWX) in North America, Europe and Asia. Additional high fidelity regions can be developed on request.
What are the data delivery options?
All GWC forecast are accessed with web services using standard web protocals. They can be delivered as a pre-spcified dataset, such as for a set of 10,000 cities delivered each hour, or as an individual forecast on a transaction basis triggered by a latitude/longitude request at a specific time.
What are the data file formats?
When accessed as datasets, GWC data are currently delivered in CSV format through through restful web services. Delivery in other formats (such as XML and netCDF) can be accommodated on request. When accessed through our API, GWC data are delivered in XML format through restful web services using the URI/http method.
What forecast horizons are available?
Hourly resolution for SensorWX and PointWX is currently available to 15 days (360 hours from forecast time). Shorter periods can be made available on request. Sub-hourly (5 or 15 minute) resolution is available for hours 1-3.
What is the data update frequency and latency?
Hourly forecasts are updated each hour. The hourly update incorporates the most recent underlying numerical model data and uses current forecasts to perform a forward error correction that ensures the forecasts do not deviate significantly from the current observations, as happens with other forecast methods. Data are available within 30 minutes of the forecast time. Sub-hourly forecasts are updated at 5 or 15 minute intervals.
Is it possible to create customized forecasts using customer-provided data or forecast engines?
Yes. A significant advantage of the modeling technology used by GWC is the ease of including customer-provided observation data or forecast engines, both of which can be implemented to enhance the quality of GWC forecasts.
Does GWC provide web clients to display the forecasts?
Yes. We have developed several web clients that we make available free to customers who use our forecast services. A variety of displays are available, including time series of all variables and time-sequence imagery of selected variables (radar, temperature, precipitation, and wind speed). Examples are shown here.
Does GWC provide imagery?
Yes. We provide both static (single image) and dynamic (image sequence over time) imagery. Current offerings include Doppler radar (U.S. and Europe), temperature, probability of precipitation, and precipitation type. These are available through our standard API.
How reliable are the data services?
They are very reliable. Services are provided from geographically redundant data centers. Reliability has exceeded 99.9% over GWC operating history. SLA terms are available on request.