I brewed up a 2.5 gallon batch of brown ale on July 5th and pitched an entire package of Safale US-04. The OG figuring in temperature correction was ~1.048. I pitched at a little too high of a temp, around 80*. When I checked on the carboy the next day it had about an inch of krausen and the airlock was bubbling away. The next day the krausen was gone and there were some yeast rafts floating around. I could tell there was still action going on because of the tiny bubbles escaping from the wort. Haven't taken another gravity reading on it, it's been sitting in primary for 2 weeks and I won't be bottling this for another week or two.
I know all fermentations are different, but is it normal for the krausen to show up after one day then disappear on day 2? The US-05 I used for my first brew had the krausen grow over a couple days and stayed like that for close to a week.
EDIT: The ambient temp for fermentation was around 65*F. I lost my liquid crystal thermometer strip somewhere before I could attach it to the carboy