 Meanwhile, the west will remain dry and it will become hot again in the afternoon through parts of California into the southwest. This will be a part of a major heat wave developing through the rest of the holiday week into the weekend. Highs in the valley areas will easily reach into the 100s, with many places surpassing 110. It will be much more comfortable across the northwest. I'm ACKIEWEATHER.com meteorologist Matt Rinde.