As San Diego braces for a heat surge, the National Weather Service (NWS) San Diego forecast predicts a temperature spike. Highs today are set to reach 5 to 10 degrees above the norm, especially searing in inland areas. While coastal residents might enjoy the upper 70s to borderline 90s, inland valleys are prepping for low 100s, and low desert areas might endure scorching 110 to 114 degrees. The NWS also cautions that an Excessive Heat Warning remains firmly in place for the low deserts.