"Oh yes. My special talent is seeing the future! Something could still go wrong, my spell's not perfect, but I know we can get everything done well in advance because I checked."
"...Really. I have a particular interest in magic, how does your spell work?"
"Well, it takes a little while to cast, and then I get a picture of a likely future around wherever I'm going to be or sometimes somewhere else if I try really hard! It's basically 'the future if everything goes according to plan', I think, but I've never had a serious magic-type pony go over it with me. It can get thrown way off if somebody makes a choice that wasn't just about decided on when I cast the spell. Joy's trying to tone down his wackiness for the day so I can use the spell to see how the decorations will turn out before we invest all the labor in putting them up, but usually he throws me way off, and other ponies can too."
"I hope my arrival hasn't thrown a horseshoe in your predictions."
"Nope! If you're from Canterlot you must have left hours ago, the spell's had plenty of time to catch up. Wanna see me cast it?"
"Yep, everything looks great, except it looks like I was at risk of confusing the roses and the daisies, whoops! I'll just put those up right now in their correct places." Guiding trots out and then back in, a bouquet of each in tow, and tucks them into their ribbons one and then the other. "Oh, if you wanted to know, the choir goes up there on that balcony, and the catering tables are over there."
The named party sticks his head and one arm in an open window, high above them. "I'm up here, beribboning the roof! Hi!" He waves.
"Hi!" Clarity calls back. "Well, it looks like you have everything handled here."
And off she trots, following Silver Streak's directions to her sister's place to issue a reminder about clearing the sky.
Just as Streak promised, there is a tower on the far side of town, some distance down the road from the main cluster of buildings and set a little ways back from the street. As Clarity approaches, mysterious sounds emerge: clanging, clinking, and a crackling whoosh almost like a strong wind.
"Just a miiiinute!" calls a voice that is similar to Streak's, but used very differently. In four syllables, this pony has varied her tone more than Streak did in her and Clarity's entire conversation.
"Hi!" she says cheerfully. "What's up?"
"Hi, you must be Brightblaze. I'm Clarity Bell, and the Princess sent me here to oversee the preparations for the Summer Sun Celebration -"
"Oh gee, that's today?" she says. "That's totally today, isn't it."
"Well, it's technically very early in the morning tomorrow, but the sky should be cleared, and you're on my list as responsible for that."
And she disappears back into the tower. A moment later, the clanging resumes.
Clarity isn't sure whether that was intended to be the end of the conversation or not, so she stays put for another minute in case Brightblaze is going to come back of her own accord.
It takes about ten seconds to get them all. Then Blaze arcs down toward the front of the tower, brakes by pointing her hooves at the ground, turns off the boots, and lands beside Clarity in normal pegasus fashion.
"What'd I tell you?" she says, grinning.