So apparently this happened:
As we can see here, Kerrigan apparently receives some sort of powerup in the form of becoming Primal Zerg, which apparently means... doing...this.




Yeaah.





So anyways, for some measurements,















The ratio of the storm's diameter to the planet's is 1:~4.99. If we're to assume that this planet is Earthlike in size, that would be a storm diameter of (((12742 km x 435.63 px) /2175 px) x 1000 to convert to meters) = 2552090.8 meters in diameter. Halved, the radius is 1276045.4 meters.
Now, for the timeframe, I can really only assume that the giant roar accompanied with the laser beam is what generated these evillooking clouds; there is no reason to assume that her simply waking up did. So,
Based on these two shots, I have a timeframe of 8.25 seconds.Now, I'm uncertain how I'd go about deriving an energy output from this, but if we're to assume that it is expanding outwards from the central point as it appears to be in the few seconds that we get a good look at the storm from above, then we can use our timeframe in conjunction with our radius to derive an attack speed maybe?
1276045.4 meters / 8.25 seconds = 154672.17 meters/second, or Mach 454.53. This translates to Massively Hypersonic going by our speed tables.
Neat.
Anyone wanna help me find an energy output for this...?
Edit: Actually, I'll take Aiden/Weekly's suggestions on this and go with DontTalk's method (thanks to all three.)
I guess the timeframe it took to generate the storm doesn't matter...?
First up, finding the area: it's roughly circular in shape, so area of a circle is probably most useful here. Translating our radius back into kilometers, we have a radius of 1276.0454 km, which we can plug into an areaofacircle calculator to get 5115429.8 m^{2}. However! There are lots of gaps in the clouds due to their spiraling shape, and they don't take up the whole circle: to be safe, I'm axeing twothirds of the total area.
(5115429.8 / 3) / 665 = 2564.125,
x 6.0 x 10^14 Watts = 1.5383 x 10^18 Watts (Joules per second), or 367.663 Megatons of TNT. Mountain level.
Keep in mind, this is probably waaaaaaaaaayyyyy lowballed seeing as she generated this in a single attack and lasts whoknowshowlong afterwards.
Edit: Actually, I doubt I need to remove twothirds of the mass. If you look a bit closer, there's actually storm clouds throughout the whole thing: they're just harder to see because they're more similar to real storm clouds than this big, red, sinisterlooking fluffy stuff. This means that (367.663 x 3)/1000 = 1.103 Gigatons of TNT (Small Island level) is likelier in my book.
Final Tally
Sarah Kerrigan's EvilLooking Cloud Expansion: 154672.17 meters/second
Sarah Kerrigan's Storms of Doom Energy Output: 367.663 Megatons of TNT  1.103 Gigatons of TNT