SYNOPSIS:
A strong ridge of high pressure extending from northern Quebec through southern Ontario is bringing cool and dry air into the region. Despite the sunny skies, temperatures will be below seasonal through tomorrow due to northeast winds. As high pressure slowly slides east and allows a southerly flow of warmer air to develop on Wednesday, temperatures will slowly return to seasonal average. A frontal boundary will then move into southern Ontario Wednesday morning and will develop showers in Toronto by the mid afternoon hours that will continue into the evening.
MORE DETAIL:
Under clear skies, temperatures will dip to near -5C overnight but cooling will be limited as east winds over the lake will help our temperature level out (without the east winds we would get much cooler). We will once again have sunny and dry conditions with some high cirrus edging into the region throughout the day; evidence that warmer air is moving towards the area. Temperatures will creep into the high single digits as the cold and dry air mass currently in place becomes modified. Showers will move into the GTA sometime after 2pm and become more organized as the afternoon comes to an end. The showers will likely start off very patchy and localized as most of the activity will evaporate before reaching the surface (virga) because the air will be very dry at the onset of precipitation. Once the air becomes slightly saturated, the showers will become better organized through the late afternoon and into the evening. In total, between 4 to 8 mm of rainfall is expected. The wet weather will be very short lived and fairly localized, as conditions will clear quickly overnight and into Thursday morning.
