An Associated Press analysis shows that the recent heat wave struck places that are warming up faster than other parts of the United States. Federal weather data since 1990 show that during the summer, the West is heating up more than elsewhere. So the Northwest heat wave is not as surprising as it looks. The AP analysis also finds that in the West daytime highs are rising faster, producing those triple digit stunners. But in the East, nighttime lows are getting warmer faster than daytime highs are. And experts say nighttime cooling is needed for the body to recover from daytime heat.