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If you’ve come here from EWRadar’s #BootsandHearts weather updates, head to [this page] to go to our Boots and Hearts live radar feed With support from the Weather Channel and Environment Canada. Canadian Tire Mosport Park (“Boots and Hearts”) is located just NE of map centre. Quick guide – green – overcast to light rain. Yellow – moderate to heavy rain, light thundershower. Red – heavy rain, moderate to severe thunderstorm. Pink, purple – take cover!
Have a great weekend – wish I was there!

For more southern Ontario weather monitoring go to our main pages at


We recently re-added realtime METAR (Aviation Routine Weather Report) rosettes to the Scan B radar displays. The attached image shows the rosettes for Kithener-Waterloo and near Fergus, Ontario. These reporting stations are usually sited at airports and may or may not be automated. Their currency may lag by up to 2 hours, although they usually more current than that.

The rosette EWR displays consists of a centre circle, to which a wind vane is attached, and is surrounded by three or four numbers.

The centre dot may contain one of the following codes: M – no sky cover report (ie “missing”; a full white dot (clear sky), a full black dot (fully cloudy), or a partial black/white dot that is quartered in black and white in proportion to the relative cloud cover. In the image, the KW cloud cover is “50%”. Additionally, our METAR dots will also show a red down-arrow (sharply decreasing pressure) or a green up-arrow (sharply rising pressure). These latter two items report in relation to storm cells typically. The outer rim of a storm cell will be strongly high pressure due to the storm cell downdrafts and outflow winds, while the storm centre or core will show a strong low pressure due to rising air in the cell. These rapid changes are indicative of a strong convection cell, and should be viewed as indicative of potentially severe weather imminent.

The wind vane radiating from the centre dot indicates direction the wind is coming from; the “feathers”, the strength of the wind, in knots. There are two scale lengths to the feathers, long and short. A long feather is 10 knots, a short feather, 5 knots. The vane itself represents a 5 knot breeze.

The top left number in white is the reported temperature in degrees Fahrenheit. The lower green number is the dew point. The upper right number is the last 3 digits of the atmospheric pressure in kilopascals, ie, for Fergus, “237” is 1023.7 kpl.

Other chart symbols may show from time to time (we have no control over what comes down the METAR feed) – this chart link will show the many symbols which may turn up, depending on what’s on the feed at the time.


While the official NOAA position is that 2013 will be an active hurricane season, other experienced watchers believe that’s not necessarily the case. For current tropical storm activity, you can follow the season for the Atlantic and Eastern Pacific at our Atlantic and Eastern Pacific Hurricane Activity 2013 page.

I’ve added a Twitter account for the EWR Blog, EWRadar, as distinct from the Twitter account EWRWxAlert so that posts from the EWR blog pages will now auto-post to twitter.

The pages will remain focused on tweeting out the alerts, so that followers are not cluttered by tweets unrelated to specific severe weather events.

Also, this hurricane season, I’m separating out specific named-storm information into their own EWR blog posts (see Tropical Storm Debby) rather than embedding the information in the general season overview at Atlantic and Eastern Pacific Hurricane Activity 2012. The overview post continues its previous functions, linking to the named-storm posts rather than having the information embedded. This will make tracking and archiving specific storm info easier and reduce the clumsiness in the overview post when multiple named storms are in play.


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RSS Last Alert Issued:

  • GH-GTA Scan Zone Severe Weather Alert #ONStorm October 2, 2016
    SEVERE WEATHER ALERT — 01:35 PM EDT Oct 02 2016 This is an automated alert of potentially severe weather for the Golden Horseshoe/ Greater Toronto/Niagara Peninsula/South-Central Ontario Monitored Area, from Ephemerata Weather Radar. See attached scan image. The alert triggered at 01:35 PM EDT on Oct 02 2016, from radar data analyzed from NWS radar site KBUF […]

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