Head for the waters around the mouth of the Yak out of Columbia Park. The entire area is teeming with huge carp. Every channel I came across this past weekend was full of fish; it was almost eerie the way these fish were crashing through the reeds and rolling everywhere. There are some great articles on this site covering tackle and techniques for these great gamefish!
Fishing for carp is best when it is bright and sunny, and the sun is right over head. I went fishing this evening around 6pm, but our shadow was really spooking the carp. We still managed to land a cpl each. When the sun is directly overhead, seeing the carp isnt a problem, and there is no shadow to spook them. Be sure to have polarized glasses and a hat though.
As far as tippet is concerned, i use 15 lb green maxima. Carp arent leader shy at all.
Carp love warm water, so temps in the 100s isnt an issue, just be sure to bring lots of H2O