 I'M STACEY LYNN. EXTREME HEAT IS BLANKETING MUCH OF THE COUNTRY, AND IT'S GOING TO STICK WITH US FOR A FEW WEEKS. HERE'S CBS'S ADRIANA DIAZ. FROM THE MEXICAN BORDER ALL THE WAY UP TO CANADA, TEMPERATURES ARE SOARING. THE HIGH HEAT CREATING A TINDERBOX FOR WILDFIRES OUT WEST. IN CALIFORNIA, RECORDS MORE THAN A CENTURY OLD COULD MELT. WHILE ALONG THE TEXAS COAST, PREPARATIONS AND SOME EVACUATIONS ARE UNDERWAY FOR TROPICAL STORM BARREL