Thunderstorm Outlook for Canada and the United States for Monday, July 23rd 2018.

There is a risk of severe thunderstorms in Southern Alberta including the City of Calgary, Northern, and Central Manitoba will see a chance for Funnel Clouds.   NW Ontario, and SE Ontario will also see non-severe thunderstorms.  The main threats here are Large hail, heavy downpours, and winds guts up to 100 km/h, as well as a elevated Tornado risk.  

United States
Severe thunderstorms are expected in the  NE, and the SE states.   The main threats for these storms are; large hail, wind gusts, heavy localized downpours, and a risk for a few Tornadoes.       

The thunderstorm forecast is issued daily from April 1 to September 30.
Definition of a Severe Thunderstorm 
In Canada, a rainfall rate greater than 50 millimetres (2 in) in one hour, or 75 millimetres (3 in) in three hours, is also used to indicate severe thunderstorms. Severe thunderstorms can occur from any type of storm cell. However, multicell, supercell, and squall lines represent the most common forms of thunderstorms that produce severe weather.

A thunderstorm is classed as severe if winds reach at least 90 km/h (58 mph), hail is 25 millimetres (1 in) in diameter or larger, or if funnel clouds or tornadoes are reported. Although a funnel cloud or tornado indicates a severe thunderstorm, a tornado warning is issued in place of a severe thunderstorm warning. A severe thunderstorm warning is issued if a thunderstorm becomes severe, or will soon turn severe.
Thunderstorm Safety Tips:
  • Move to a sturdy building or car.
  • Do Not take shelter under isolated trees.
  • Get out of boats and away from water.
  • Unplug appliances. Avoid using the telephone or any electrical appliances. 
  • Do not take a bath or shower.
  • Remember when thunder roars go indoors!

The Enhanced Fujita Scale (EF-Scale) rates the strength of tornadoes in Canada and the United States based on the damage that they cause. 

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