San Diegans can expect a surge of monsoonal moisture leading into the weekend, with the National Weather Service San Diego forecasting a chance for mainly afternoon showers and thunderstorms on Thursday and Friday, particularly in the mountainous areas. The San Bernardino Mountains are singled out as having the highest likelihood of rainfall. According to an NWS update, the potential for heavy rainfall will peak on Friday, though any developing storms throughout the region could bring moderate to high precipitation rates.
In more detailed guidance, the National Weather Service notes that the depth of the marine layer will hold steady at about 2000 feet, which is expected to usher coastal low clouds into the western valleys each late night. A weak low-pressure system from the south is the catalyst for the uptick in atmospheric moisture, and while Thursday will see a slight cooling for desert regions, temperatures generally are on an upward trend. By next Wednesday, high temperatures could end up a few degrees warmer for most areas, notably so for inland regions. However, the chances for one-quarter inch or more of rainfall have remained around 10 percent each day, with the chances for one-half inch or more rainfall being less than 5 percent.
Looking ahead into early next week, moisture will taper off with an overall drying trend indicated for the weekend. This gradual shift accompanies a slight warmth increment in the high temperatures expected from today through next Wednesday. “High temperatures for Wednesday of next week will range from around average for the deserts to as much as 5 to 10 degrees below average for portions of the valleys,” as detailed in the Area Forecast Discussion by the National Weather Service…