I've got a down jacket with a pertex shell that I just put a 2 cm rip in, and some feathers are coming out. It's a golite, and they said I can mail them back the jacket and they will mend it, but it's winter and I need to wear this jacket.

What are acceptable ways that I can mend this tear?
Can I stitch it up with a regular thread and needle? Is there a patch kit for this sort of thing?

Thanks!

I used McNett Tenacious tape on my down jacket to repair a medium sized, L-shape ax wound.

I've used Tenacious Tape to mend a Western Mountaineering sleeping bag - it will hold up all winter, and then come off when you get it repaired right.

It's pricey, but well worth it!

For a down jacket, the neatest way to patch it is to slide the tape into the hole and patch it from the inside... I tore my FA Down Jacket bushwhacking yesterday, and I'm about to try that myself.

Based on your location, I'd suggest calling Ripstop Repair in Boulder, making arrangements ahead of time to somehow have the fix expedited, and have them do it. They go in from the inside and the repair makes the original rip all but invisible. I've had several of my down jackets fixed for very similar damage and they do it very well, and very reasonably. If you explained your need to have it fixed rapidly, I suspect they could accommodate you.

Or, use a piece of tape.

Tape from the inside of the tear with some transparent tape to keep the edges together.
Use a bit of seamgrip to repair the tear from the outside.
Smooth with a wet finger so the repair doesn't stick out too much.
The challenge is to keep the repair stable(no movement) as it dries(A book on each side of the repair?).
Put an oval-shaped piece of the tape of choice(Tenacious, Gorilla, Gore-tex, spinnaker) over the seamgrip repair.
Done.