Good to moderate air quality expected

Weather Summary: Issued on Wednesday, March 10, 2010

A high pressure ridge over Quebec and eastern Ontario during Wednesday is causing mostly sunny skies and light winds over most regions, except for increasing cloudiness over southern Ontario ahead of a developing low pressure trough west of the Great Lakes. Increasing east to southeasterly winds are expected with temperatures continuing warmer than seasonal values. Overnight, the cloudiness is forecast to move northward over southern Ontario with some scattered light precipitation ahead of a warm front.

During Thursday, the high over Quebec and the low west of the Great Lakes are forecast to cause increasing east to southeasterly winds with continuing mild temperatures. Partly sunny skies are expected over most regions except for more persistent cloudiness over northern regions.

During Friday, the low is forecast to move slowly eastward over the US Midwest and cause cloudiness and precipitation over most of the forecast regions with continuing east to southeasterly winds and continuing mild temperatures.

Air quality indices are forecast to be in the good to moderate categories in all forecast regions during Wednesday. Thursday's air quality indices are forecast to be in the good to moderate categories in southern Ontario and mostly in the good category elsewhere. Friday's air quality indices are forecast to be in the good to moderate categories in southwestern Ontario and generally in the good category elsewhere.

Smog Alert by Email

Sign up now to receive notification of Smog Alerts

Smog, comprised of ozone and/or PM_2.5, is primarily a summer phenomenon, occurring mostly in southern Ontario; however, PM_2.5 can elevate smog levels during all months of the year. For this reason, the ministry reports the AQI hourly, seven days a week; and continues to provide air quality forecasts daily.