Temperatures are expected to climb to near 30 degrees in the Capital Region and Central Alberta this afternoon.
However, there's a good chance we'll end the day with some thunderstorms and possibly severe storms in some areas.
The primary severe threat will be wind gusts near 100km/h.  Heavy downpours and hail are also likely with a few of the storms.

For the Capital Region - those storms (if they hit) may not hit the area until this evening or overnight.
Areas further NW and W will get them a bit earlier.

An Upper Low swinging into northern Alberta will provide the cooling aloft needed for these storms to strengthen. And...it looks like that Upper Low may stick around for a few days.
Most models have it lingering over northern Alberta until Thursday. So, the northern half of the province will be cool (highs in 15-20 range), cloudy and wet. Much of the Peace Country and areas near Fort McMurray will get 15-25mm of rain by late Wednesday. Some spots could get closer to 40mm. Areas outside of those regions will get a chance of some showers Tues/Wed - but it won't be as heavy or steady.

Edmonton:
Cooling to a high near 20 Tuesday with a chance of a few showers.
Cloudy, high near 18 and some showers in the area Wednesday.

Warmer air moves back in for the end of the week with highs returning to the low to mid 20s in the Capital Region.

Here's the Edmonton forecast:

Today - Mix of sun & cloud.  Wind easing this afternoon.  
High:  29

Tonight - 40% chance of a thunderstorm early-evening.  70% chance of a storm late this evening and/or overnight.
Wind becoming NW 30 gusting to 50km/h (stronger near thunderstorms)
9PM:  22

Tuesday - Mix of sun & cloud.  40% chance of showers.
Wind:  W 30 gusting to 50km/h
Morning Low:  13
Afternoon High:  20

Wednesday - Mostly cloudy.  60% chance of showers.
Morning Low:  12
Afternoon High:  18

Thursday - Mix of sun & cloud.
Morning Low:  12
Afternoon High:  21

Friday - Mix of sun & cloud.  30% chance of a late-day shower or thunderstorm.
Morning Low:  11
Afternoon High:  23

Saturday - Partly cloudy.
Morning Low:  12
Afternoon High:  24