Up to 50mm of rain could hit Fort Saskatchewan and area this weekend.
A storm cell is expected to pass through the heartland Friday afternoon (Jun.22), with the worst scheduled for Saturday.
"A long extended trough of low pressure looks like it'll move over the Fort Saskatchewan area and stay for the next couple days," said John Paul Cragg, Environment Canada's warning preparedness meteorologist.
Highs are still in the 26-28 C range.
"Because they're so slow-moving there is the chance of very heavy downpours," added Cragg.