About the Forecasting Contest

  1. To join the contest, first register on the site by clicking on the "Create new account" link in the left sidebar. The username you choose will appear in all of the contest results. You may enter information about yourself in the "About Me" section, including your real name, but you can remain anonymous if you wish. You will receive an e-mail asking you to log into the site with your new username and immediately choose a password.
  2. If your school class is participating, your teacher will probably send in a list of names and everyone will be automatically registered ahead of time.
  3. Each forecaster is in a "division" and mainly competes against others in that division. School classes usually have their own division. If you're not part of a class, you will probably compete in the "Open" Division (for anyone).
  4. Once you are registered, you may enter your first forecast by going to the site page for the location you are interested in, using the Sites menu in the header. At the bottom of the page there will be a form allowing you to enter Tmax, Tmin, precip and an optional comment for the next available forecast day. Check your forecast carefully to be sure you didn't make a mistake. If you want to correct something, you can just submit another forecast for the same day and it will override any earlier forecasts.
  5. For most divisions, forecasts are made each weekday, Monday through Friday, for daily maximum and minimum temperatures (deg F) and total daily precipitation amount (inches) for the next day (Tuesday through Saturday).
  6. Most contestants will probably be interested in only one location, but anyone may submit forecasts for more than one location if they wish.
  7. For most divisions, forecasts are submitted each weekday anytime before 9:00 pm local time. The forecast period begins a few hours later, at 0600 UTC (1:00 am EST), and runs to the next 0600 UTC. So forecasts for sites in the Eastern Time Zone submitted before 9:00 pm EDT on Monday cover the period from 1:00 am EST Tuesday until 1:00 am EST Wednesday. Contestants will not be able to see the forecasts made by other contestants until after the submission deadline. They will however, be able to see all of the available MOS forecasts and their own.
  8. A division can be set up to forecast for different days of the week and/or to have a different submission deadline. For school classes, the teacher may decide to do that.
  9. The submission deadline is the same whether it is Standard or Daylight Saving Time.
  10. Verification for the contest is based on the National Weather Service reports of six-hour Tmax, Tmin and precip amount. The reports from 1200, 1800, 0000 and 0600 UTC are combined to calculate the daily values. If the NWS has observing problems or data transmission problems at a site and we can't get the complete set of numbers for a day, we will flag some or all of the variables for that site, so that all forecasters would receive zero error scores for those variables. Think of it as a rainout, so to speak.
  11. For each day, the object is to have the lowest number of total error points. One error point is assigned for each degree (F) that the forecasted Tmax and Tmin differs from the observed values. A logarithmic function is used to calculate precipitation error points. This results in relatively large errors for relatively small departures when precipitation amounts are light, and smaller errors for larger departures when precipitation amounts are greater. The Tmax, Tmin and precipitation error points are added together to get a daily score.
  12. Each day, those error scores for everyone who submitted a forecast in a division are used to assign division points. If there were 10 forecasts, the best one gets 10 points, the second best gets 9 points, etc., and the worst forecast still gets 1 point. If only one forecaster submitted a forecast, they get 1 point and everyone else gets none. So the goal is to submit forecasts for as many days as possible, and to have better forecasts (lower error scores) than the other forecasters in your division.
  13. If your division submits forecasts from Monday through Friday, you can still submit a forecast for other days, it just won't count in the contest. So just do it for fun or practice.