Temps to drop 10-15 C by Wednesday with strong wind and intense rain across southern Alberta

A deep upper trough in British Columbia is the main weather maker for central and southern Alberta right now.

Strong winds are expected to precede this low pressure system as it tracks across the Rockies throughout the day Tuesday and gusts of up to 80 km/h are possible.

As that low enters central Alberta, the counter clockwise rotation of the system will meet resistance from the physical barrier of the mountains, resulting in upsloping flow and heavier accumulations in areas along, and east of the foothills.

Typical of systems with an upsloping element, it is difficult to pinpoint the most vulnerable locations for maximum precipitation accumulations but there is certainty that there will be widespread rain Tuesday and Wednesday with a notable amount of moisture.

Cooler air associated with the low will drop daytime highs by as much as 15 C in some communities on Wednesday (compared to Tuesday) and overnight lows will be close to freezing in the mountains.

As a result, snow is possible in some of the higher elevation locations but any snow that falls closer to the surface in the foothills will not last.

Calgary is forecast to receive at least 15 and up to 30 millimetres of rain during this event.

As quickly as conditions deteriorate, they are expected to recover just as quickly.

Thursday’s highs will bring temperatures back to what they were on Tuesday in most of southern Alberta, and the warmest temperature of the week in Calgary will happen on Friday.