Description
- The Global Forecast System (GFS) is a numerical weather prediction model run by the national weather service. The model produces forecasts up to 16 days into the future, but with decreased spatial resolution after 8 days. Forecast temperature data for today (day T+0) through day 7 (day T+7) is derived from the GFS. The GFS model is run 4 times per day, at 0000 UTC, 0600 UTC, 1200 UTC, and 1800 UTC and numerical output is updated twice daily, at roughly 12:30 am EDT and 12:30 pm EDT.
- Extended T+8-14 day forecasts are issued by the Climate Prediction Center (CPC) based on GFS data and other long-term models showing the probability that certain regions will be above or below average. Based on historical patterns, a Powerburn Energy model converts these probabilities into forecast temperatures and degree day data. Forecasts are issued daily, but numerical data is only updated Monday-Friday
- In the tables and maps available here, temperature data is presented in the form of degree days, a measure of projected temperature-dependent energy consumption. Cooling degree days (CDDs) are calculated by subtracting 65 from the mean daily temperature [(max temp + min temp)/2] to produce an estimate of cooling demand. Heating degree days (HDDs) are likewise calculated by subtracting the mean daily temperature from 65 to produce an estimate of heating demand. Total degree days (TDDs) are the sum of both heating and cooling degree days for a region.
- To produce national and regional estimates of temperature-dependent natural gas demand, forecast data for 158 large urban centers is analyzed. State TDDs are calculated by weighting these cities (usually 2-10 per state) based on their populations. Likewise, regional estimates for each of the three natural gas regions--East, West, and Producing--are calculated by weighting state estimates based on the population of that state compared to the population of the region. Finally, national estimates are calculated by weighting these regions relative to the population of the nation
- In addition to forecast high/low and degree day data, maps and tables highlighting the departure from historical averages and the change in forecast degree days from one model run to the next (12 hrs for the GFS, 24 hrs for the extended 8-14 day outlook) are also available.
|
|
Tabular data
Raw GFS and CPC data for 158 US cities organized by region and state. Forecast high/low, CDDs, HDDs, TDDs, departure, and model trends are organized by city, state, region, and country.
|
Maps
Forecast Total Degree Days, Departure From Average, and 12-Hour Degree Day Trend maps, mapped at the state level.
|
No comments:
Post a Comment