BCAS Weather
Maps:
Environment Canada
The Weather Network
Current Moon
Phase
Weather Links
Clear Sky
Clock Port Elgin,
Clear Sky Clock Owen
Sound
Find a Clear Sky Clock for your area
How to Read Clear Sky Clock
Clear Sky Clock - Port Elgin
At a
glance, it shows when it will be cloudy or clear for up to the next two
days.
Courtesy of
Canadian Meteorological Center {CMC} // How to Read Clock
(see below)
Clear Sky Clock - Owen Sound
At a
glance, it shows when it will be cloudy or clear for up to the next two
days.
Courtesy of
Canadian Meteorological Center {CMC} // How to Read Clock
(see below)
Find a clear sky clock in your area
http://cleardarksky.com/csk/prov/Ontario_clocks.html
The Weather Network - Port
Elgin
http://www.theweathernetwork.com/weather/cities/can/pages/CAON0555.htm
The Weather Network - Owen Sound
http://www.theweathernetwork.com/weather/cities/can/Pages/CAON0515.htm
Environment Canada - Port
Elgin
http://weatheroffice.ec.gc.ca/city/pages/on-19_metric_e.html
Environment Canada - Owen Sound
http://weatheroffice.ec.gc.ca/city/pages/on-19_metric_e.html
Other Weather Links:
Sun &
Moon Rise/Set Tables
Environment
Canada's Weather
Global Hydrology & Climate Center
Great Lakes Satellite Image
http://www.theweathernetwork.com/weather/cities/can/pages/CAON0555.htm
http://weatheroffice.ec.gc.ca/forecast/city_e.html?on-19
Hiddenwell Observatory Clear Sky Clock
How to Read the Clear Sky Clock:
Summary: Find a
blue block in the first row. There probably wont be any clouds in the sky
then.
Details: Read the image from left to right. Each column
represents a different hour. The first two coloured blocks in the columns are
the colours from CMC's forecast maps for Port Elgin, for that hour. The two
numbers at the bottom of a column is the local time, in 24hr format, of that
hour. (Local time for Port Elgin is -5.0 hours from GMT.)
The image
above shows one hour resolution. But currently CMC forecasts only every 3
hours. CMC is planning true hourly resolution for summer 2002. In the meantime,
the Clock image above will typically show the same colour for each triple of 3
hours.
The line labeled cloud: is visible-light cloud forecast.
It forecasts percentage cloud cover. Dark blue is clear. Lighter shades of blue
are increasing cloudyness and white is overcast. This forecast may miss low
cloud and afternoon thunderstorms. CMC's text page explaining this forecast is
here.
The line labeled tran: is the transparency forecast. Here
'transparency' means just what astronomers mean by the word: the total
transparency of the atmosphere from ground to space. It's calculated from the
total amount of water vapor in the air. Dark blue means excellent transparency
befitting Arizona. Light blue is better than average and pale blue is worse
than average. White means that there is at least some broken cloud. Look at the
cloud forecast for the same time to see how much cloud there will be. The
transparency forecast seems to be somewhat pessimistic. CMC's text page
explaining the this forecast is here.
The line labeled darkness:
is not a weather forecast. It shows when the sky will be dark, assuming no
lightpollution and a clear sky. Black is a dark sky. Deep blue shows
interference from moonlight. Light blue is full moon. Turquoise is twilight.
Yellow is dusk and white is daylight. For those who prefer numbers, the scale
is also calibrated. Mouse over a darkness block for details. The colours
represent the limiting visual magnitude at the zenith. The legend row at the
bottom shows the magnitude that each color represents from mag 6 for a dark sky
to mag -4 for daylight. It is based on Ben Sugarman's Limiting Magnitude
calculations page. It takes into account the sun and moon position, moonphase,
solar cycle and contains a scattering model of the atmosphere. It doesn't
consider light pollution, dust, clouds, snow cover or the observer's visual
acuity. So your actual limiting magnitude will often be different.