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Usage Notes

General

All Wind directions are relative to True North.

The wind, temperature, pressure and humidity charts were developed using the Highcharts library. Features of Highcharts include the ability to display conditions at any given time by hovering your cursor over a chart, and the ability to highlight or de-select certain properties by clicking on that property a the chart's legend. Highcharts is a commercially-available charting library available at no charge for not-for-profit organizations like NSC.

Wind Data Accuracy and Reliability

The Weather Station is mounted on the lighthouse at the harbour entrance. Winds from the northwest to the northeast reach the weather station unimpeded, providing reliable wind direction and strength readings. However, winds from the northeast to the northwest (in a clockwise direction) are obstructed by land, trees and buildings, and thus both the wind strength and direction are more variable than on the lake, and the wind strength will generally under-report the winds on the lake. The weather station does accurately report the winds at the station, but that may not be a reliable indication of the winds on Lac Deschênes.

Note: When no new data is available, either because the Weather Station is down, the communication link is inoperative or the WeatherLink Cloud storage is offline, the last available values are used, resulting in constant-value (straight-line) plots.

Weather Station Data

The NSC's weather station sensor uploads a block of data every 5 minutes to the Davis Weatherlink Cloud Storage through a small device connected to the internet via the office router. Every 5 minutes starting on the hour, the NSC web server downloads a block of "current" data from the WeatherLink Network and stores the time, wind, temperature, humidity and pressure values in a running 6-hour file. When you open or reload this page, the 6-hour file is downloaded by your web client and processed to generate the charts below. To update the charts, reload the page.

The wind speeds, gusts and directions, plotted in 5-minute increments, use "last 2-minute average" values. Note that this is different from the 1-hour increment plots in the 7-day History page which use "last 10-minutes average" values. Therefore, the hourly values displayed in this page and the 7-day History page will differ.

The data on the Weatherlink Network is also available to other weather websites, including Weatherlink, Weather Underground and CWOP. The NSC Weather WLL graphic immediately below is from the Davis Weatherlink site. The seasonal rainfall will reset on May 1 each year. Unlike the other plots, this information is automatically refreshed every minute.

Wind Direction

The wind direction polar plot is also known as a Radar Plot; it shows the most recent wind direction at the outside of the polar plot, similar to the depiction of the original NSC "Windicator". When the wind drops below 1.0 knot, the plotted direction is frozen until the wind increases to at least 1.0 knot.

Wind Frequency

The wind frequency polar plot is also known as a Wind Rose. The average wind data values are grouped by speed and direction according to one of 7 speed ranges and 16 compass (cardinal) points. Groups are plotted as color-coded sectors.

Wind: Prevailing & Gusts

This chart shows prevailing wind strength and direction (based on True North) on an X-Y scale. When the wind drops below1.0 knot, the directional arrow is replaced by a small dot. The vertical axis adjusts its scale automatically to accommodate the winds over the previous 6 hours.

Temperature, Pressure & Humidity

Self-explanatory, similar to the chart, "Wind: Prevailing & Gusts".

Water Level

The water level chart uses data from the Environment Canada Water Office's Hydrometric data for station 02KF005 (Britannia). The data file is refreshed every 1 hrs (Apr-Oct), or 4 hrs (Nov-Mar). Be advised that there are occasional data gaps, characterized by constant levels over several time intervals, as well as occasional data lags when no new data is reported.

When the water level data is not available (depths being logged as 99999 in the data file), a "no data" message is displayed instead of the graph. When data collection resumes, the graph shows whatever data is available over the past 12 hours.

Disclaimer

NSC does not warrant the quality, accuracy, or completeness of any data presented in this page. The following weather information is provided on an "AS IS" basis without warranty or condition of any nature.

Suggestions? Errors?

Please contact the developer, Daniel Servranckx.

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