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The RASP forecasts show the regional soaring prediction for each of the next three days. Each page shows a collection of forecast images for 14:00 Eastern Daylight Time (EDT). The maps cover the flying region of the three local soaring clubs. Resolution is 4 km. Lake Ontario is clearly visible in the south west and the St. Lawrence Seaway extends from its eastern tip. Contour intervals are shown at 250ft. Sections of the Ottawa River often appear as blue blobs in the correct geographical location.

The forecasts are produced on a dedicated server and the results sent to the web site for display. The approximate update times are given at the top of each day's images. Each forecast requires approximately 18 minutes of computing time to generate after the most recent initialisation data is downloaded from the National Oceanic and Atmospheric Administration in the USA. Forecasts are more accurate in the shorter term. Predictions for each of the approaching three days are compiled overnight and are available early every morning. Updates are issued throughout the day (minimum 6 hour interval), with priority given to the current day.

For an explanation of any image consult the definitive source at

Viewing an animated sequence

If you click on a particular graphic, you will see an animated hourly sequence depicting conditions from 10:00 to 17:00 EDT. The animation is assembled and updated a few minutes after the 14:00 EDT images become available. The approximate animation update times are shown when the mouse is hovered over a 14:00 EDT image. The animation pauses briefly at the end of the sequence before playing again.

Notes on forecast update times

Forecast images are updated as new predictions are compiled. The static 14:00 EDT images are available before an updated animation sequence can be constructed. Consequently, an older animation may be displayed for up to about 5 minutes following a very recent 14:00 EDT forecast.

Publishing of the forecast images is controlled by a process that runs every five minutes. If you are anxiously awaiting an update and it is close to the time of normal availability, refresh 20 seconds after the next five-minute marker is reached (e.g. 11:05, 11:10, 11:15...). The server is accurately synchronized with an atomic time source on the internet.

Airport Legend - (not currently in use)

  • A Arnprior

  • al Alexandria

  • B Brockville

  • cp Carleton Place

  • G Gananoque

  • H Hawkesbury (MSC)

  • I Iroquois

  • L Lachute

  • M Morriburg

  • P Pendleton (GGC)

  • pe Pembroke

  • S Smiths Falls

  • R Rideau Valley Soaring (Kars)

  • W Winchester

  • wp Westport

Known issues

Occasionally, problems occur during production of the RASP. Sometimes data calculated at one stage of processing causes a subsequent stage to fail. In this circumstance it is not possible to build a continuous animation sequence and an embedded gap will result. You can determine the missing hour by closely monitoring the animation. When there is a failure affecting the 14:00 EDT forecast, the static images are not available although a textual link to the animation sequence remains. In this case, a gap at 14:00 EDT will occur during animation.

Forecast production months

Daily production of the Regional forecasts creates an intense computational load on the computer producing the prediction. To conserve resources during a period when there is no local soaring activity, daily forecasts are suspended from November 1 to April 14.

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