Cooler weather, storms forecast this week in San Diego County

A shift in weather patterns will bring cooler conditions and a chance of afternoon storms to the region this week, according to the National Weather Service. Temperatures Tuesday are expected to reach 74 near the coast, 75 to 78 inland, 76 tp 81 in the western valleys, 83 to 88 near the foothills, 85 to 95 in the mountains and 108 to 112 in the deserts. High pressure is expected to weaken Tuesday into Wednesday, leading to temperatures 8 to 12 degrees below normal in the valleys. By Thursday and Friday, a weak upper-level low from the south will draw in monsoonal moisture, increasing the potential for afternoon showers and thunderstorms — especially across mountain and high desert areas. The greatest storm chances are expected Friday, the NWS said. Moisture levels and storm chances will gradually decline over the weekend, according to meteorologists. Meanwhile, night and morning coastal low clouds are forecast to spread into western valleys each evening.