San Diegans can expect a reprieve from typical July heat this weekend, with temperatures forecasted to be well below the average for this time of year. The National Weather Service in San Diego has reported Saturday's highs will range from the upper 60s along the coast to the low 100s in the lower deserts. Specifically, coastal areas will experience temperatures from 68 to 75 degrees, while inland valleys can expect 77 to 85 degrees.
The forecast indicates that this will be "the coolest day of the week," which starkly contrasts the usual warm mid-summer temperatures. The cooling trend is attributed to "a weak trough of low pressure moving inland into California," according to the Area Forecast Discussion by the National Weather Service San Diego. Saturday's highs aim to quickly drop to 15 degrees below average, particularly for mountainous regions and inland valleys.
However, residents won't need to get too accustomed to the cooler weather. Beginning Sunday, temperatures are expected to creep upward once again. Strengthening high pressure to the east will bring a warming trend for Sunday through Wednesday, with highs on Wednesday projected to reach within a few degrees of average for late July. The Inland Empire, specifically, can anticipate temperatures from the 80s to the lower 90s on Sunday, with the lower deserts hitting between 102 and 106 degrees.
The current marine layer, noted to be around 2000 feet as of early Friday morning, will deepen to approximately 2500 feet for Saturday, likely resulting in night and morning coastal low clouds spreading into the western valleys. The marine layer is slated to decrease in depth once again Saturday night into Sunday, from 2000 to 2500 feet. This fluctuation may allow to slowly introduce more uniform low clouds back into Orange County and inland valley regions faster than this morning.
