Drought and Heat stress. Some plants (mainly fruit trees) will jump into bloom during periods of extreme stress - its mother natures way of trying to squeeze one last chance at seedlings out of a difficult year.

If the weather forecast calls for temperatures below about 40F, you might want to dig the bulb up, with as much of the root ball as you can, and take it inside to enjoy the flower. I have known leaves to survive temps into the high 20's (for an hour or two), but wouldn't want to guarantee the flower bud surviving. You can either have the bulb as a house plant for the winter, planting it out in spring when the frost danger has passed, or plant it back outside when the flower is done, bearing in mind the bulb might be strong enough to give another flower stalk. Whatever you do, feed it well, as flowering takes a good bit out of a bulb.

If you get lucky, and the stalk grows faster than normal, and you don't want to dig the whole thing up, you might be able to cut the stalk and enjoy it in a vase - I would wait until the first bud was almost ready to pop, though, and Ma Nature may not wait that long to give us a frosty night.

I wondered if the stress caused it. . .Will be sure to bring it inside if the temps cool off drastically. What a treat to have blooms at this time of year!