Wednesday, 11 July 2012

Humidex advisory and Severe Thunderstorm Risk


      Humidex values will be pushing 40 today in all of southern Manitoba, reaching as far north as Swan River and the northern Interlake. It is recommend that you reduce strenuous activities outdoors during the peak heat hours of the afternoon in particular. Temperatures this afternoon are expected to reach between 33 and 35°C, and that will be mixed with dewpoints near 20°C.

     In addition, a severe thunderstorm watch has been issued for the western half of the province, all the way up to the Nunavut border. This is due to a trough of low pressure moving east from Saskatchewan. Areas that may see severe storms this afternoon and evening include the Melita, Brandon, McCreary, Dauphin, Swan River, Grand Rapids, Thompson and Tadoule Lake areas. The main threats today are torrential downpours, large hail and damaging winds. Tornadoes are unlikely due to low shear, however in July they can never be completely ruled out.

     It is expected to remain hot and humid Thursday and Friday, and as a result, it will be an uncomfortable next few days. Thunderstorms, some severe, will remain possible both days as well.


  1. Official high in Winnipeg today was 34.5°C, with a peak humidex of 42. Tropical!
    Portage reached 35.8°C, while Gillam in northern Manitoba hit 36.4°C with a humidex of 42!
    Severe storms are now pushing into northeastern Manitoba, with severe thunderstorm warnings in Island Lake. Main threat seems to be the winds with gusts over 90 km/h measured.

  2. Today's the day we have to watch out for localized flooding. These thunderstorms today are slow movers, and are producing very heavy rain given the humidity around. As a result, if you get a direct hit by a thunderstorm, 50 mm of rain will be possible in a short period of time. Frequent lightning is also likely today, along with large hail and damaging winds. Will update during the day. Forecasts will be updated within the hour.