TWCT/TWCC Forecasting Contest Rules
Contest Objective: During a two-week round, contestants will create ten weather forecasts for a particular city. Each forecast will be valid for a calendar day (midnight to midnight local standard time for that city as defined in the NWS climate summary). The forecasts will only be for Monday through Friday, so no forecasts will be made for the weekends. Contestants may use any source available to compose their forecasts, but any forecast must be the contestant's own effort. Each forecast must have the following four elements:
1. The high temperature in whole degrees Fahrenheit
2. The low temperature in whole degrees Fahrenheit
3. The probability of precipitation (POP) in a percentage ranging from 0% to 100% that is in 10% increments (0%, 10%, etc.)
4. The liquid precipitation amount (liquid equivalent if frozen precipitation occurs) in hundredths of an inch (0.00", 0.01", etc.)
City Requirements: Any city used in this contest must be in one of the fifty states of the United States, have a functioning ASOS weather station, and an official NWS daily climate summary for that station to ensure accurate and complete verifications. All verifications will be performed by using the NWS climate summary, which relies on data that has been quality controlled from the ASOS weather station. If any missing data occurs during a day that would impact the contest, efforts will be made to resolve the missing data if possible. If the missing data cannot be resolved accurately, then contestants that submit a completed forecast on that day will receive zero error points for the affected forecast elements.
Forecasting Deadline: All forecasts for a particular day are strictly due at 12:00:00 AM EDT (or EST when DST is not in effect) for the start of that day. Thus, if you are forecasting for tomorrow, your forecast is due at midnight EDT (or EST) tonight. If you do not live in Eastern Time, you must adjust this deadline accordingly. The forum time will be used to verify that all forecasts meet the deadline. Contestants will make a post with a forecast of the required four elements that are listed in the Contest Objective section. If you need to make changes to your original forecast post, please make sure all edits or corrections are made before the deadline, which will be determined by the last edit time of your post. If your forecast is incomplete, is submitted or edited after the deadline, or is not submitted at all, it will be considered as "missing" and will be subject to the penalty described in the Missing Forecast section.
Dishonest Forecasting: If a contestant intentionally copies a forecast from another contestant that was previously submitted for the same day, or if a contestant intentionally makes a forecast that is completely unrealistic, the forecast will be considered as "missing" and will be subject to the penalty described in the Missing Forecast section. All of the TWCT/TWCC forum rules also apply here, and any repeat offenders will be disqualified from this contest entirely and will be issued forum warnings. This contest is simply for fun and educational purposes, so please respect all contestants regardless of performance.
Forecast Scoring: All forecasts will be scored by accruing a total amount of error points for any imperfections against the final verification values from the four categories shown in this section. A perfect forecast will earn zero error points. Since weather forecasting is so difficult to where even the best forecasters can bust, mercy rules have been inserted so that the worst outcome for a single forecast in any of the four categories listed here is 10 error points:
High Temperature - 1 error point for every degree Fahrenheit off, and any errors more than 10°F will result in the maximum of 10 error points
Low Temperature - 1 error point for every degree Fahrenheit off, and any errors more than 10°F will result in the maximum of 10 error points
POP - For verification purposes, 0% is used when 0.00" or a trace of precipitation occurs, and 100% is used when at least 0.01" of precipitation occurs. Using the Brier Score concept that statistically gauges the skill in forecasting an event with two distinct outcomes, the forecast POP is subtracted from the verification POP, and the result is squared. Scaling is then performed to make a possible range of 0-10 error points as shown here:
Forecast POP off by 0% - 0 error points
Forecast POP off by 10% - 0.1 error points
Forecast POP off by 20% - 0.4 error points
Forecast POP off by 30% - 0.9 error points
Forecast POP off by 40% - 1.6 error points
Forecast POP off by 50% - 2.5 error points
Forecast POP off by 60% - 3.6 error points
Forecast POP off by 70% - 4.9 error points
Forecast POP off by 80% - 6.4 error points
Forecast POP off by 90% - 8.1 error points
Forecast POP off by 100% - 10 error points
Liquid Precipitation Amount - 0.1 error points for every 0.01" off (trace amounts of precipitation are considered as 0.00" due to not being measurable by NWS definitions), and any errors more than 1.00" will result in the maximum of 10 error points
Missing Forecast: Any forecast that is deemed as "missing" for any of the reasons given in these rules will accrue the maximum amount of error points from each of the four categories plus an additional penalty of 10 error points. Thus, any missed day will result in a total of 50 error points. Meteorologists have to meet strict deadlines as part of their real jobs, so even submitting a forecast that may not be your best effort is far better than missing the deadline completely.
Winner Determination: After a two-week round is completed, the contestant with the fewest total error points from all ten forecasts will be declared the winner for that city. If there is a tie, the contestant with the fewest total error points from the second week (the final five forecasts) for that city will be declared the winner. The winner will be given the privilege of selecting the next city for this contest, but this city must be in a different time zone than the last city that was completed and must also comply with the requirements stated in the City Requirements section. This stipulation ensures that a wide variety of meteorological conditions will be encountered during this contest. Once a new city is chosen, all scores will be reset to zero so that everyone starts with a clean slate in the next round.
