Omaha-Offutt AMS Forecast Contest Rules

Last updated: March 28, 2008

You do not have to be an AMS member to participate, but only dues-paying member of the chapter are eligible to win prizes.

Each user will be uniquely identified by a 5 to 9-digit ID number and password chosen by the player, as well as his/her name and e-mail address. Your ID number and password should never be shared with other players. Any attempts to tamper with the contest or another player’s entries will be grounds for immediate dismissal from the game. Problems with entries or identifying information (e.g., needing a new ID number, changing a contact e-mail) must be identified via an e-mail to the forecast contest administrator, Matthew Sittel (mcsittel@cox.net). Do *NOT* add a second account! The online entry form will be the ONLY acceptable method for contest entries; the administrator shall not be responsible for entries not received due to computer problems or other communications issues.

Each contest period will last 7 days, starting at midnight local time each Saturday. Two cities will be used each week. One will always be Omaha Eppley, while the other will change from week to week. In addition, 3 multiple choice questions covering the same 7-day period will be asked, as well as a temperature forecast range question for a selected city in the US or Canada.

You may enter each week between the time the new week’s entry form is available on the web site through the weekly deadline. The entry deadline each week will be 5 pm CT Friday, 7 hours before the start of that week’s 7-day forecast period. Late entries will not be accepted. You may change your forecasts during the week by entering a new forecast, but only your last entry prior to the deadline will be used as your forecast.

Entrants will forecast the 7-day period’s maximum and minimum temperature, as well as total precipitation. Temperatures should be entered in whole degrees Fahrenheit (e.g., 78), while precipitation should be entered in inches and hundredths (e.g., 1.35”). Only one multiple choice answer can be selected from the possible responses. The values for the range question should follow the same convention as outlined above for the 7-day forecasts.

Consensus, climatology, persistence and GFSx Medium Range Forecast entries will also be added to each week’s suite of forecasts. Their values will be determined as follows:

Consensus: the average temperature and precipitation values of all entries. Its multiple choice response will be the most-commonly given response. In case of a tie between multiple responses, the first one listed will always be selected. The consensus range will be the average width of all responses, and extend that distance downward from the average maximum temperature of all entries.

Climatology: The maximum temperature will be halfway between the 7-day forecast period's average maximum, as taken from the 30-year climate normals, and the coldest record high for the same 7-day period. Similarly, the minimum temperature will be halfway between the 7-day forecast period's average minimum, as taken from the 30-year climate normals, and the warmest record low for the same 7-day period. Precipitation will be the 7-day summed value of the daily climatological normal amounts. Climatology will always answer "A" for all multiple choice answers. The range will be the difference between that day's normal maximum and minimum.

Persistence: the maximum and minimum temperatures plus total precipitation for the previous 7 days ending on the Thursday prior to the forecast due date. For example, if the due date was November 9, persistence would use the extremes and precipitation from the November 2-8 period for both cities. Persistence will always answer "B" for all multiple choice answers. The range will be the average diurnal range of the 7-day persistence period.

Medium Range Forecast: the 12Z run on the forecast deadline date will be used. Precipitation will be the cumulative QPF for all available periods, taking the center point of each listed QPF category as the 24-hour amount. GFSx will always answer the last choice for all multiple choice answers (i.e., B, C and D for the 3 questions, respectively). The range will be the 7-day maximum minus minimum temperature for that location as forecasted by the same 12Z run.

Verification

Verifying values will be taken from the F6 products issued for each city by its governing National Weather Service office for the 7-day period, or from Environment Canada's climate data in the case of Canadian cities. Should data be missing due to problems at the observing site, an attempt will be made to determine verifying data from hourly observations. Failure to establish verification may result in a contest week being cancelled, and will not count towards the season-long standings.

Scoring

Error points will be cumulative throughout the season, and be accrued as follows:

Maximum and minimum temperature: 1 point for each degree the forecast is away from the verifying value
Total precipitation: 1 point for each 0.10” the forecast is away from the verifying value.

Bonus points will be awarded as follows:

2 points for a correct answer to multiple choice question 1 (which will always have 2 possible answers)
3 points for a correct answer to multiple choice question 2 (which will always have 3 possible answers)
4 points for a correct answer to multiple choice question 3 (which will always have 4 possible answers)
5 points for an exact temperature forecast
2 points for an exact precipitation forecast when verification is zero (i.e., no rain)
The points for an exact precipitation forecast when verification is greater than zero (i.e., rain falls) is determined from the following formula:

2+floor(20*x), where x is the precipitation verification in hundredths of inches, and floor is the next lower integer of this product.

For example, if 0.24" rain fell, a correct forecast will earn 2+floor(20*.24) = 2+floor(4.8) = 2+4 = 6 points.
A 0.5" rainfall, if correctly predicted, is worth 12 points. A 1" rainfall is worth 22 points for an exact forecast. The greater the rainfall, the more points earned for an exact forecast.
Points for the range question will be awarded when verification falls within or on the bounds of the stated range, and increases as the width of the range narrows, using the following scale:

Range Width	11+	10	9	8	7	6	5	4	3	2	1	0
Bonus Points	1	2	3	4	5	6	7	9	12	15	20	30

Weekly and season-long winners will be the player(s) with the lowest cumulative point total for that period.

Penalties

A forecaster who fails to enter a weekly forecast will receive the consensus entry for his/her forecast. Two missed forecasts are allowed without penalty. Starting with the 3rd missed forecast, 6 penalty points will be given, multiplied by the number of missed forecasts over and above the allowed two during the season. For example, the first two missed forecasts simply earn the consensus error. The third missed forecast adds 6 error points to the earned consensus error, the fourth adds 12 error points to consensus error, etc.

Prizes

The top 3 season-long contest winners will win prizes. Also, those not in the top 3 will be eligible to win one of 5 additional prizes for the best human weekly forecasts during the season (i.e., consensus weeks are not eligible for the best weekly forecast prizes). All prizes will be awarded at the last chapter meeting of the year. If the player is not able to attend, he/she will be contacted via the e-mail account entered at registration to arrange for award delivery.

Schedule Disclaimer

The contest schedule posted on this web site is tentative, and its contents may change during the season due to unforeseen circumstances. Similarly, the contest end date may change based on the last chapter meeting date.