Warm & humid with strong thunderstorms by Wednesday

The yellow arrows show smoke over Ontario drifting into Quebec and New England late last week and into the weekend. The haze and smokey air is travelling along the jet stream from wildfires burning in Alberta and B.C. (NWS Burlington)

Well almost immediately after I guaranteed a spectacular weekend on Friday, mother nature began to challenge that claim, at least for some of us. A colder than normal air mass over the Great Lakes managed to produced afternoon clouds and even some scattered showers over Ontario as far east as the Ottawa Valley. However sunshine and only some high cloudiness prevailed in Montreal. Temperatures responded in the sunshine making it to 28C (83F) on Sunday for metro Montreal, while it was only 23C (73F) in the clouds in Toronto. Another shot of much cooler than normal air will arrive in Ontario and Quebec and the US Midwest by Thursday but until then it will be very warm and humid. Partial sunshine can be expected both today and Tuesday in southern Quebec with just some high clouds and perhaps some haze and smoke form the western wildfires. Highs will make it close to 30C (86F) both days. On Wednesday a cold front will arrive with clouds and showers along with the risk of a few strong thunderstorms. Highs will be cooler reaching 26C (79F). By Thursday sunshine will return with a much drier and more comfortable air mass and highs near 22C (72F).

The moist, unstable air has Toronto down to 1 kilometer visibility in fog and mist this morning, with a special weather statement in effect for much of southwest Ontario for dense fog. The fog should burn off in the next few hours, but until then travel is slow with visibility locally as low as zero on some highways.