The National Weather Service in San Diego is forecasting a cool down for the San Diego region starting Friday, with high temperatures on Saturday expected to dip as much as 10 to 15 degrees below average for the inland valleys and mountain regions. A weak trough of low pressure is to thank for the weekend chill, which will be especially noticeable in the higher elevations, according to NWS San Diego.
Friday's temperature drop, moving inland into California, will offer a slight reprieve from the recent heat, especially for those in the inland valleys where the highs are slotted to hover in the upper 70s to mid-80s. Moving towards the coast, residents can expect more moderate temperatures ranging from 70 to 76 degrees. However, the lower deserts will continue to sizzle, with forecasts hovering around 100 to 105 degrees. The Area Forecast Discussion notes that the high temperatures for the inland valleys and mountains will significantly drop from the norm by Saturday.
Meanwhile, the marine layer remains a persistent player, with its depth hovering around 2000 feet and showing patchier coverage over coastal areas compared to recent nights. As it deepens to about 2500 feet by Saturday, a greater coverage of night and morning coastal low clouds is expected. According to the NWS San Diego, these clouds will slowly creep further into the western valleys each evening, a move that's echoed in Friday into Saturday's modest cooling trend.
Looking ahead, a warming trend will kick off on Sunday as high pressure builds to the east. This will send the mercury rising back up, with high temperatures projected to sit within a few degrees of average on Wednesday. Per the NWS San Diego's Area Forecast Discussion, inland areas will see temperatures rise back into the mid 70s to 90s, with the lower deserts experiencing a 106 to 110 degrees baking. Despite the upcoming heat, the marine layer will become shallower over time, restricting night and morning coastal clouds to a smaller footprint in the western valleys.
Furthermore, the forecast suggests a possible minor influx of monsoonal moisture by the latter part of next week, hinting at a slight chance of afternoon thundershowers for the mountains starting Wednesday. The chances remain low for now, with Skywarn spotters not being requested to activate just yet. However, all eyes will be on the skies next week as the weather evolves.
Marine conditions look to remain mostly uneventful, save for the expected gusts at around 20 knots in proximity to San Clemente Island in the afternoons on Thursday and Friday. Boaters and marine enthusiasts are unlikely to face any major concerns through the early part of next week.
