As Southern California braces for a scorching week, the National Weather Service (NWS) in San Diego warns of temperatures soaring to potentially record-breaking highs across inland areas. According to NWS San Diego, inland valleys and deserts will experience weather as much as 15 to 20 degrees above average, with the mercury set to climb to the upper 90s to 106 for the inland valleys. In comparison, the lower deserts can expect a sizzling 110 to 115 degrees.
The heat is due to a high-pressure system expanding across California, which is set to bring warm weather so much as today is the hottest day for the desert regions. Amidst this heatwave, a Heat Advisory remains in effect through Thursday 8 PM PDT for several areas including the Coachella Valley and surrounding desert locations. Meanwhile, a Dense Fog Advisory complicates morning commutes in Orange County, remaining in place until 10 AM PDT.
A shallow marine layer along the coast keeps temperatures relatively cooler, but at night and in the morning, low coastal clouds and fog sometimes extend into the western valleys. The marine layer is slightly shallower than on Monday, resulting in coastal low clouds and fog that are not extending quite as far inland, according to the NWS's Area Forecast Discussion.
Moreover, the inland regions are under heightened fire weather concern through the weekend due to extreme heat and low humidity, which is expected to fall to 10 to 15 percent in the afternoons. A weak coastal eddy may bring some relief in the form of a slight humidity recovery for valleys, but only briefly before hotter temperatures resume on Saturday and Sunday.
Marine activities are also affected, as patchy dense fog with visibility of 1 nautical mile or less is expected again tonight into Wednesday morning, particularly impacting ocean-going vessels. Apart from these foggy conditions, no significant marine hazards are anticipated through Saturday. While Skywarn activation is not requested, weather spotters are encouraged to report any significant conditions as the week progresses.
