, °F

Personalized Forecasts

Featured Forecast

My Favorite Forecasts

    My Recent Locations

    Brett Anderson

    Share |

    Update on Severe T-storm and Alberta Rainfall Potential

    May 22, 2013; 3:02 PM ET

    Storms are now starting to fire over SW Ontario and should continue to intensify as the air mass out ahead of the storms de-stabilizes.

    The graphic below shows where the best chance of potentially damaging (straight-line winds/small hail) storms will be into this evening. Thunderstorms will weaken late this evening and the threat for severe thunderstorms will be done for the overnight period. Tornado threat is low, but you can never totally rule it out with this type of setup. Also, there was a possible tornado yesterday in the Kawartha Lakes area.

    ------

    Major cool down then a storm

    The leading edge of much cooler air will track southeastward over the next day or two then stall out as low pressure forms near Long Island. This storm will drift northeastward into the weekend as a blocking high pressure area out in the Atlantic causes the storm to almost stall for a time. This situation could lead to significant rainfall (25-75 mm) through the weekend over New England and perhaps into parts of the Maritimes as the humid air off the Atlantic overruns the much cooler air coming down from the north.

    ---------

    Heavy rainfall and flooding potential for parts of Alberta Thursday into Friday

    The slow-moving upper-low that has been sitting over the Pacific Northwest will drift eastward tomorrow and Friday. The counter-clockwise flow around the upper low will cause a moist, upslope flow into southwestern Alberta, leading to significant rainfall. The cold air aloft will also create more instability.

    Upslope winds can lead to significant precipitation as the moist air gets lifted into the higher elevations and cools. As the air cools it condenses out as precipitation.

    Below is my latest estimate for rainfall....

    The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com

    Comments

    Comments left here should adhere to the AccuWeather.com Community Guidelines. Profanity, personal attacks, and spam will not be tolerated.

    More Canadian Weather Blog

    • Weekly long-range update

      September 23, 2016; 12:01 AM ET

      Mild air masses likely to outnumber the chilly air masses for a good part of October.

    • Pattern gets blocked up next week

      September 21, 2016; 12:02 PM ET

      Jet stream pattern across North America will become amplified across North America into next week, which means more extremes in weather.

    • Weekly long-range update

      September 16, 2016; 11:20 AM ET

      Warm weather will dominate in the eastern half of the country for the next week. Pattern change possible during the last week of September.