For those basking in the unusually warm temperatures in San Diego, the heat wave is set to continue as the temperatures west of the mountains are soaring above normal trends. Coastal areas have been enjoying the warmth, with temperatures ranging between 64 to 74 degrees, while valleys and inland Orange County are pushing the mercury with a high of 72 to 82 degrees. According to the NWS San Diego, high deserts will see highs of 66 to 70 degrees, and the low deserts are even warmer at 78 to 82 degrees. However, a cool down is anticipated come Sunday, bringing the temperatures back to their seasonal norms.
Meanwhile, forecast discussions from the same source hint at a change in the weather pattern starting early next week; a trough of low pressure is making its way southward across the western United States, set to stir up a cool down and introduce moderate to possibly strong Santa Ana winds from Monday through Wednesday. The Area Forecast Discussion cites, "A trough of low pressure amplifies and dives southeast through the interior West Sunday and Monday," which promises a continued onshore flow for Sunday and should bring back some coastal low clouds and fog for Sunday and Monday mornings. However, the offshore breezes today and tomorrow could gust up to around 30 mph in the foothills.
Visibility has also been an issue in the mornings along the coast and western valleys, where dense fog has reduced road clarity. The National Weather Service advised extra caution during morning commutes and predicted the fog would give way as the offshore flow strengthened, leading to mostly clear skies through Saturday. They also note areas of dense fog will continue this morning, but the overall coverage is decreasing. For aviators, coastal shallow low clouds have presented challenges with 200-600 ft MSL bases and visibility down to 0-3 SM. Improvements are expected after clearing around 15-17Z.
The anticipated Santa Ana event brings a fire weather concern, with very low humidity levels expected to plummet to 10-20% away from the coast. The discussion from the National Weather Service adds, "Santa Ana winds will move into the area Monday, peak in strength Tuesday morning, and gradually fade through Wednesday" while also indicating that locally critical fire weather conditions may arise due to the combination of low humidity, strong winds, and dry fuels, particularly on Tuesday. Residents in the regions susceptible should remain vigilant during this period and heed any cautions or directives issued by local fire departments and forestry services.
